ABSTRACT OF PAPERS - NEMATOLOGYnematology.in/data/documents/V11N01P95.pdf · 2019-08-20 · with...

Indian J. Nematol11 (1981) 95-135

ABSTRACT OF PAPERS

Presented at Nematology Symposium held at Coimbatore, Indiain February, 1981

CROP LOSS ASSESSMENT IN BRINJAL DUE TO ROOT-KNOT NEMATODE

MELOIDOGYNE INCOGNITA : K. Krishnappa, K. G. H. Setty and K. S.Krishna Prasad, Department of Plant Pathology, University of Agril. Sciences,Hebbal, Bangalore-560024.

A field experiment was condueted to assess the crop loss due to root-knotnematode, Meloidogyne incognita in brinjal at the main Research Station,Hebbal, Bangalore. Randomized complete block strip trial was adopted withpaired treatments in a nematode sick plot. Plants were protected with aldicrab(Temik lOG) at the rate of 8 kg a.i.jha applied a day prior to transplanting in fivereplications. Another set of unprotected plants served as check. Significantdifferences in plant growth and vigour were observed in shoot height, freshweights of shoot and root and length of roots between protected and unprotected plants. The root-knot index in the scale of 1-5 was 0.7 in protected plotscompared to' 4.71 in unprotected plots. There was a significant increase in fruityield per plant in protected plots. The per hectare fruit yield was 20,500 kgsin treated plots as against 11,300 kgs in unprotected check plots. Thus, 44.87per cent yield loss could be accounted to be due to root-knot nematode alone ina heavily infested field.

EFFECT OF 60 COBALT RADIATION ON THE GROWTH AND DEVELOPMENT OF MELOIDOGYNE GRAMINICOLA IN RICE ROOTS: K. S.

Krishna Parsad, Y. S. Rao and K. Krishnappa, Department of Plant Pathology, University of Agril. Sciences, Hebbal, Bangalore-560024.

Well developed egg masses of Meloidogyne graminicola on rice cultivar'IR-8' were radiated in 60 Cobalt at 2.534 kilorads for 10 minutes. The infecti

vity and development of larvae hatched from this treatment was compared withlarvae of untreated egg masses at weekly intervals following inoculations to

96 ABSTRACT OF PAPERS

'IR-8' rice seedlings. Though the infectivity of radiated larvae did not differ,there was a delay in their development in rice roots. The egg mass productionin radiated females was delayed by about a week compared to untreated femaleswhich produced egg masses in about four cweeks. The IInd, IIIrd and IVthdeveloping stages within the rice roots did not show much differences in theirsize, but the females, developed from radiated larvae, were smaller as comparedto their untreated counter parts. However, the fecundity of these nematodeswas not affected as observed by all most equal number of eggs per egg masswhich were of same size. Further, the next generation of larvae from thesefemales developed normally like their untreated counterparts.

FACTORS EFFECTING LARVAL EMERGENCE FROM CYSTS OF THE

MAIZE CYST NEMATODE, HETERODERA ZEAE: A. C. Verma andB. S. Yadav, Department of Nematology, Rajasthan College of Agriculture,Udaipur, Rajasthan.

Effect of different media, cyst age, light and darkness, temperature, hydrogen ion concentration and root diffusates of maize varieties on larval emergencefrom cysts was investigated. Double distilled-water and sandy soil diffusate werebest for larval emergence. H. zeae showed maximum per cent emergence fromwhite than brown cysts. Light and darkness did not influence emergence. Nohatching occurred at lOoC and 40°C and the optimum temperature was 30~C.Hatching was observed from 4.0 to 11.5 pH with an optimum of 10.5 pH but notat 3.5 or lower pH levels.

MOVEMENT OF OXAMYL IN SOIL COLUMNS: R. P. Singh, S. K. Saxenaand Abrar M. Khan, Section of Plant Path'ology and Nematology, Dept. ofBotany, Aligarh Muslim University, Aligarh.

The movement of oxamyl in soil was studied in laboratory columns byleaching it with distilled water. Distribution co-efficient for the absorption ofoxamyl by soils was calculated to determine the amount of water 'required toleach oxamyl upto a depth of 152.4 gms. These values would be helpful indesignIng suitable control methods where average rainfall or irrigation water isknown.

ABSTRACT OF PAPERS 97

EFFECT OF DIFFERENT SALT LEACHA TES ON THE MOVEMENT OFNEMATICIDES IN SOILS USING THIN-LAYER-CHROMATOG

RAPHY: R. P. Singh, S. K. Saxena and Abrar M. Khan, Section of PlantPathology and Nematology, Dept. of Botany Aligarh Muslim University,Aligarh.

Movement of dazomet, oxamyl, dichlorofenthion in soil with differentsalt leachates has been measured in termS of frontal Rf-values with the help ofthin-layer method of chromatography. The movement of dazomet and oxamylwas highest in saline salt leachates and that of dichlorofenthion in alkaline saltleachates. The movement of all the three nematicides differed at various soil

porosites.

EFFECT OF VARIOUS INOCULUM LEVELS OF ROOT-KNOT NEMAODE,MELOIDOGYNE INCOGNITA ON BRINJAL, SOLANUM MELONGENAL. : B. D. Yadav and A. C. Verma, Department of Nematology, RajasthanCollege of Agriculture, University of Udaipur, Udaipur.

Pathogenic studies on brinjal (PPL) indicated that presence of ten thous

and larvae of M. incognitalplant at the time of transplanting is highly pathogenic tothe crop and significantly reduce the plant growth and increases multiplicationof nematode population. Light infestation of ten and hundred larvae per platnwas found to increase plant growth. The nematode multiplication rate was higherat such lower larval population.

EFFECT OF TEMPERATURE ON LARVAL EMERGENCE FROM HETERO

DERA A VENAE CYSTS: D. S. Bhatti and Indra Malhan, Department ofNematology, Haryana Agricultural University, Hissar.

Effect of constant temperatures, i.e., 10, 15, 20, 30 and 40°C on larvalemergence from old and new cysts of Heterodera avenae and of fluctuating roomtemperature, from only old cysts, was studied during 1973-1975. The contentsof field - collected cysts were recorded during April, 1973 to November, 1974,In all, there were 100 cysts in four replicates at each temperature. The object ofthis study was to determine optimum temperature for larval emergence inH. avenae both under controlled and naturally fluctuating temperatures. The weekly

98 ABSTRACT· OF PAPERS

observations revealed that differences in larval emergence from old cysts at lOoc,lSOC and 20"C were significant. As is evident from total hatch, the optimumtemperature might be around 20°C. However, at fluctuating room temperature,the maximum larval emergence took place at 18°C, this observation points tothe possible existence of optimum temperature between 15)C and 20°C. Forlarval emergence from new cysts, there was significant increase at 15°C as compared to 10'C, a significant decline at 20°C and little emergence at higher temperatures. This indicated that for larval emergence from new cysts the optimumtemperature might be between 10°C and 15°C. Thus there appeared to be different temperature optima for larval emergence from old and new cysts ofH. avenae. The difference in temperature optima of cysts of varying ages may provide an explanation for variance between cyst numbers per unit of soil and thelarvae emerging in field, causing varying pathogenic effects on host crops. Further, the total emergence of larvae during one season might be governed by theproportions of new and old cysts in which they are present in infested fields. Theobservations on contents of the field-collected cysts did not show much greatervariation except a slight decline during winter months.

EFFECT OF SOIL TEXTURE ON THE DEVELOPMENT OF HETERODERA

AVENAE POPULATION: D. S. Bhatti and Indra Malhan, Department ofNematology, Haryana Agriculture University, Hissar.

Population development of Heterodera avenae in six soil types, namely,clay, clay loam, loam, loamy sand, sand and sandy loam, was studied in 15-cmpots. Of each soil type there were four pots having one plant each, inoculatedwith 300 second-stage larvae one week after germination of wheat cv. Sonalika.The experiment was set up in December 1974 and terminated in March, 1975.The number of cysts/plant and cyst contents were recorded at the end of experiment. The data showed a· great variation in development of H. avenae indifferent soil types. Loamy sand and sandy loam were the best soils for higherrates of multiplication and development. Clay and clay loan were not suitablesoils for cyst development. The cyst content did not reflect any correlation with

soil type, but it was maximum (179.31 eggs) in loam followed by sandy loam.(136.0).

ABSTRACT OF PAPENS 99

EFFECT OF VARIOUS LAND DEVELOPMENT PRACTICES AND CROPPING SEQUENCES ON NEMATODE POPULA TIONS OF UNDISTUR~BED LAND: Arjun Lal, K ..C. Sanwal and V. K. Mathur, National Bureauof Plant Genetic Resources, New Delhi-12.

Effect of various land development practices (burning of vegetative cover,ploughing plus levelling, green manuring and summer fallowing) and croppingsequences recommended for the region (mono-cropping, mixed cropping andcrop rotation) on population dynamics of plant parasitic and soil nematodeswas studied on a land which had remained without any cultivation since longtime. All land development practices were found to decrease the numbers ofmost of the nematode species encountered. The ploughing plus levelling followed by summer fall owing and green manuring with Crotalaria juncea almost completely eliminated the nematodes. Amongst various cropping sequences, specificcrop rotations were found most effective in keeping nematode populations belowthe damaging levels while monocropping with six successive crops of tomatohighly favoured the population increase of Meloidogyne incognita, making theland unsuitable for growing a susceptible crop in the next season.

EFFECTS OF CHEMICALS AND pH ON THE ACTIVITY AND SUR VIVAL

OF THE PREDATORY' NEMATODE, MONONCHUS AQUA TICUS :A. L. Bilgrami and M. Shamim Jairajpuri, Section of Nematology, Department of Zoology, Aligarh Muslim University, Aligarh-202001.

ObservatiQJls were made on the effect of ,chemicals, pesticides and pHupon the activity and survival of Mononchus aquaticus Coetzee, 1968. Twelveconcentrations (1.0-0.001 M) of ferric chloride, cupric suifate, potassium nitrate,potassium chloride, potassium carbonate, calcium chloride, urea and ammoniawere used. Ferric chloride was most toxic in which the nematodes were unableto withstand even O.OOlM. Ammonia and potassium carbonate were comparatively less toxic at less than 0.02M. The other salts had no effect on the activityand survival of nematodes at less than 0.04M;. However, activity decreased inall higher concentrations of these chemicals. The effectiveness of the chemicalson the activity and survival could be arranged in the following order: ferricchloride> ammonia> potassium carbonate> cupric sulphate> potassium chloride> potassium nitrate> calcium chloride> urea. 'Eight concentrations of furadon 3G and malathion were used and both were very toxic at concentrations of


50 ppm and more. In lesser concentrations (5 ppm and 25 ppm) activity andsurvival periods were slightly more. The optimal pH was found to be 5.4-5.8suggesting its compatibility to an acidic habitat.

EFFECT OF SIMULTANEOUS INOCULATIONS AND PRIOR ESTABLISHMENT OF HETERODERA ZEAE MELOIDOGYNE INCOGNITA ANDTYLENCHORHYNCHUS VULGAR1S SINGLY AND IN COMBINATIONON PENETRATION OF H. ZEAE AND M.1NCOGNITA INTO MAIZE

ROOTS: R. K. Kaul and C. L. Sethi, Division of Nematology, IndianAgricultural Research Institue, New Delhi-12.

Three day old seedlings of maize (cv. Ganga-5) were inoculated with 50larvae of H. zeae or M. incognita, either singly or in combination with 50 individuals each of the species in glass vials (7.5 x 2.5 cm). The experiment comprisedof six treatments. Similarly in an another experiment comprising of 12 treatments, 3 day time interval was given to one or two of the species to establishthemselves before addition of the inoculum of the 3rd species. The observationson the number of larvae penetrated into root system were recorded at one day .interval for 7 days. Penetration continued upto i days with the majority penetrating by 4th day. In case of simultaneous inoculations, M. incognita did notseem to interfere with penetration of H. zeae. As against this M. incognita wasadversely affected by the presence of H. zeae occsrring singly or in combinationwith T. vulgaris. Even though presence of T. vulgaris in simultaneous inoculations tended to increase penetrations of both the endoparasites to varyingdegrees, its earlier establishment affected their penetration. adversely. In generalprior establishment of any of the species, either singly or in combination, significantly reduced the invasiveness of both the other species. Lar"al penetration ofboth the nematodes was more whenever these were inoculated earlier.

POPULATION FLUCTUATIONS AND VERTICAL DISTRIBUTION OF

XIPHlNEMA INSIGNE LOOS, 1949 IN SOIL AROUND THE ROOT OFCITRUS AURANTIFOLIA L.: B. Mukherjee, R. Mukherjee, and M: K.Dasgupta, Plant Pathology Laboratory, College of Agriculture, VisvaBharati University, Sriniketan~731236 (W.B.)

Seasonal population fluctuations of Xiphinema insigne was studied in afifteen years old citrus orchard in West Bengal during 1978-79. Composite soil


cores were taken at depths 0-20, 20-4011nd 40-60 cm under the drip line. Monthlysamples were cbllected adjacent to the previc us ones, prcceeding around the treedrip line for 12 months period and the prevailing population of the nematode wasestimated. Population maxima waS attained in the month of March-April andAugust-September, corresponding with minor and major root flushes of treerespectively. In other months, the population ranged from 20-125 per 250 mlof soil. Influence of depth on population number was observed with X. insigne.There were few nematodes below 40 cm depth. Relative prevalence data insummer and winter months showed that they were drought and heat resistant.

A SIMPLE METHOD FOR INOCULATION AND PRODUCTION OF SYMPTOMS BY RADOPHOLUS SIMILIS ON COCONUT: P. K. KoshyandV. K. Sosamma, Nematology Laboratory, Central Plantation Crops ResearchInstitute Regional Station, Krishnapuram P. O. 690 533, Kayangulam,Kerala.

Raising sprouts by dehusking seednuts partially by retaining a tuft of fiberscovering the eyes of the nut was found to accelerate germination and make rootsavailable six weeks earlier for easy handling in the laboratory. Using this method,characteristic elongate orange coloured lesions could be detected on coconutroots under a stereoscopic binocular dissecting microscope after 24 hours ofinoculation with Radopholus similis.

STUDIES ON INTERACTION BETWEEN MELOIDOGYNE INCOGNITA ANDROTYLENCHULUS RENIFORMIS ON GRAPEVINE SEEDLINGS : K.Tirumala Rao and A. R. SeshadFi, Department of Entomology, College ofAgriculture, Andhra Pradesh AgricuItl}ral University, Rajendranager,Hyderabad-30.

The interaction studies with Meloidogyne incognita and Rotylenchulus reni

formis has shown that the reduction in root length was more by M. incognita (57per cent) than by R. reniformis (34 per cent). The shoot weight and root lengthreduction at 200 level by M. incognita alone was more than either by R. reniformis alone or the combination of both the nematodes. In general, when boththe nematodes were inoculated, the interaction effect was suppressive being additive in respect of nematode population. Both were antagonistic to each other in


combined inoculations, suppressing the population of the other, with increasinglevels of their respective inoculum. The suppression effect by M. incognita wasmore on R. reniformis.

INFLUENCE OF SOIL TEXTURE AND MOISTURE ON PRATYLENCHUSDELATTREI LUC, 1958 POPULATION : Sivagami Vadivelu and T. S.Muthukrishnan, Tamilnadu Agricultural University, Coimbatore-641 003.

Pot culture studies were conducted under glasshouse condition to assessthe effect of three types of soils - clay loam, silt loam and sandy loam onthe population build up of Pratylenchus delattrei and its relative effect onthe growth of Crossandra undulaefolia. The highest population of 4038 nematodes was observed in silty loam as against 3284 and 2988 nematodes inclay loam and sandy loam soils respectively after sixty days of inoculationof the nematode at the rate of 1 nematode per ml of soil at the timeof planting. The nematode inoculated plants in the three types of soil showeddistinct reduction in plant growth, the per cent reduction (shoot weight)

being 9.92, 11.70 and 16.68 respectively in silty loam, sa!ldy loam and clay loamsoils. However, there was no conspicuous variation in root weight. In ananother experiment with clay soil in glazed pots, the effect of soil moisture onthe nematode population was studied. Four levels of soil moisture, 32~~ (saturation), 24% (three-fourth saturation) 16~~ (half-saturation) and 8% (one-fourthsaturation) were maintained an_dthe build up of nematode population on the hostplant, Crossandra cv. orange was assessed 90 days after the initial inoculation of100 nematode in 1000 g of soil. Moisture level of half saturation point recordedthe highest reproduction value (R) of 28.32 al' a~ill'st 2.89, 11.09 and 19.66noticed in 32, 8 and 24 per cent moisture levels respectively. The maximumshoot length and root weight was noticed only in the pots which maintained 16per cent moisture level inspite of the high rate of nematode multiplication.

DISEASE COMPLEX INVOLVING ROTYLENCHULUS RENIFORMIS AND

RHIZOCTONIA SOLANI IN OKRA: S. Kumar and C. V. Sivakumar,Tamil Nadu Agricultural University, Coimbatore-641 003.

Glasshouse studies proved that when the reniform nematode, Ratylenchulus remfarmis and the fungus Rhizoctonia solani were present, okra plants


succumbed to wilt at an early stage and when the nematode infection precededthe fungus, wilt appeared earlier than when the plants were infected first with thefungus. The fungus caused wilt 45-60 days after germination in the absence ofthe nematode, depending upon the level of inoculum and the age of the plant,while the initial injury by the nematode shortened the period to 34-43 days aftergermination. When both the pathogens were inoculated at high level 15 daysafter germination, wiit occurred 23 days after germination. A low initial/nematode inoculam preceiding the fungal inoculam also caused early wilting irrespective of the density of the latter.

EVALUATION OF EXTRACTION AND SEPARATION TECHNIQUES FORRECOVERY OF CYSTS OF HETERODERA ZEAE: Rajan and GopalSwarup, Division of Nematology, Indian Agricultural Research Institute,New Delhi-12.

Extraction and separation of cysts. of Heterodera species for experimentalinvestigations are very laborious and time consuming processes. A number oftechniques have been suggested time and again by various workers but so farthere has not been any attempt to evaluate the comparative efficacy of thesetechniques. Also the consequent effect, if any, on the emergence of larvae fromcysts as a result of handling by different techniques and which should be animportant consideration in adopting a technique' for a particular species has notbeen generally studied. This is particularly true for the Indian conditions.Sieving followed by mechanical picking of the cysts is the generally accepted proc~dure for collection of cyst inoculum required for experimental purposes. However, thiS is a very laborious process and also tiresome. Therefore, some of thealready known techniques of extraction and separation of cysts of Heteroderaspecies have been evaluated in respect of 2 important cyst nematode species,Heterodera avenae and Heterodera zeae. The present paper is confined to theresults obtained with respect to H. zeae.

For extraction of cysts, use of ZnSO. (sp. gr. 1.32) with flask was comparable to fenwick can and modified fenwick can but was inferior to sieving alone.Use of NaCl, MgSO. and sugar was not effective. A sample size of 200 ml wasfound to be significantly better sample size than 50 and 100 mL However, fornot culture soils, there was no difference between 50, 100 and 200 ml sample size.Soil type was found to be an important consideration in the selection of the


techniques to be used for extraction. For loamy sand soil dry sieving-frubbingwas better than other methods while in the case of sandy loam soil as well as potculture soil, sieving, fenwick can and modified fenwick can were equally good.

After extraction, quick separation of cysts from debri was obtained byacetone+carbon tetrachloride (drying of cyst+debri at 25'C), ethanol (dryingof cyst + debri at 15'C). However, these chemicals depressed the hatching of thecysts but other inorganic chemicals like NaCI (sp. gr. 1.19) and MgS04 (sp. gr.1.22) which were significantly inferior to acetone + carbon tetrachloride andethanol for separation of cysts from debri stimulated hatching of the recoveredcysts.

INTERACTION OF HETERODERA ORYZICOLA AND MELOIDOGYNEGRAMINICOLA IN ARTIFICIAL INOCULATION IN RICE: Y. S. Rao

and J. S. Prasad, Central Rice Research Institute, Cuttack-6.

To study the influences of Heterodera oryzicola on the multiplication ofMeloidogyne graminicola and vice versa, inoculations were made to 10 days oldplants ofrice var. CRM 13-3241, separately, simultaneously and one nematodeinoculation followed by the other 7 days after in different combinations. Observatjons were taken on the 7th, 22nd, 37th and 52nd day after inoculations. It wasobserved that the larvae of M. graminicola hatched and invaded the rootsearlier than the H. oryzicola larvae. No significant differences were found in themultiplication of M. graminicola in different levels Qf inocula or in different combinations with H. oryzicola. Multiplication in the individual inoculation ofH. oryzicola treatments was found to be superior to the treatments in whichH. oryzicola was given simultaneously with M. graminicola or H. oryzicola inoculation followed by M. graminicola after 7 days.

EFFECT OF LIGHT OF DIFFERENT WAVE LENGTHS ON SOIL EXTRACTION OF MELOIDOGYNE INCOGNITA BY IMPROVED BAER

MAN FUNNEL METHOD: S. D. Basu, B. Gope and B. Banerjee, TeaResearch Association Tocklai Experimental Station Jorhat, Assam.

Improved Baerman Funnel technique under exposures to artificial lightsignificantly increases extraction of root~knot nematodes from soil, though

,""


amongst themselves, lights of different wave lengths did not show any significantdifference in their effects on extraction efficiency. Exposures of light for 4 hoursand 24 hours significantly influenced the extraction efficiency.

INTER RELATIONSHIPS OF INFECTIVITY BETWEEN THE BURROWING

AND ROOT KNOT NEMATODES IN BLACK PEPPER, PIPER NIGRUML: M. S. Sheela and T. S. Venkitesan* Department of EntomoJogy, Collegeof Agriculture, Kerala Agricultural University, Vellayani - 695 522.

In Kerala serious damage to black pepper crop is caused due to infestationby the burrowing nematode, Radopholus simi/is and the root-knot nematode,Meloidogyne incognita. These species have been observed to infest the vinesjointly as well as separately. A pot culture experiment was conducted to studythe relative infectivity of these nematodes under the above situations. Onethousand nematodes/1.51L. of soil as initial inoculum separately, jointly or insuccession was tested under six treatments.

The treatments involving nematodes either in combinations or othewisesuppressed the growth of vines. Simultaneous inoculation of both nematodes

suppressed plant growth to the maximum extent. Inoculation of R. simi/is andM. incognita in succession led to the reduction in leaf area, internode length, topand root development. The p'opulation build up of the nematodes was found tobe accelerated when the two species were inoculated separately and there was decline in the population under combined inoculations. The root gall developmentwas suppressed in plants inoculated with M. incgnita and R. simi/is insuccession.

HOST RANGE OF THE SPIRAL NEMA TODE HELICOTYLENCHUS

ABUNAAMAI: N. N. Padhi and S. N. Das, Department ·of Nematology,Orissa University of Agriculture and Technology, Bhubaneswar-75 1003.

Of the 61 plant types, belonging to 21 families, tested in replicated potculture experiment as possible hosts of Helicotylenchus abunaamai, 38 botanicalspecies were found to be susceptible and favourable hosts taking into considerationof multiplication of the initial level of nematode inoculum. The highest nematode

• Present Address: College of Horticulture, Kerala Agricultural University, Vellanikkara-680 654,Trichur, Kerala.


population was recorded on little millet "gulji" followed by rice. The rest of the23 plant species were unsuitable, of which 12 were regarded as poor hosts and 11(niger, marigold, rape seed, mustard, karanja, radish, coriander, bitter gourd,knolkhol, and margosa) were graded non-hosts.

CYST NEMATODE, RETERODERA OR YZICOLA , ON RICE IN KERALAI. ESTIMATION OF LOSS IN RICE DUE TO H. ORYZICOLA INFESTATION, IN FIELD CONDITIONS: Usha Kumari and K. John

Kuriyan, College of Agriculture, Vellayani.

The extent of crop loss caused by cyst nematode, H.oryzicola at differentlevels of inoculm in rice variety, Triveni, was estimated in a field experiment. Itwas found that the extent of damage caused to the crop increased with the increase of inoculm levels of 6000,9000, 12000 and 18000 larvae per sq.m. Therewas a reduction of 4.39 to 7.65% in the height of the plant, 19.38 to 28.51 % inthe number of tillers, 10.07 to 28.13/~ in the number of leaves, 7.36 to 17.10~{, inthe length of ear head, 11.62 to 35.36% in the weight of shoot, 13.76 to 43.37% inthe root weight, 7.32 to 28.62% in yield per plot of 1 sq.m. and 7.75 to 36.28% ingrain weight per plot of 1 sq.m. over the control. The yield loss per plant was16.83 to 35.76~~ and 20.65 to 41.91% in grain weight per plant. There was a

correspoilding increase of ,cyst nematode population and cysts in soil and plantalso. The reduction in growth and yield characters of the rice plant was maximum at the highest level of inoculum, showing that the more the nematodepopulation, the more the damage to the plant.

HISTOPA THOLOGICAL STUDIES OF MAIZE CYST NEMATODE HETERODERA ZEAE ON MAIZE: A. C. Verma, B. S. Yadav and A. K. Pathak,Department of Nematology, Rajasthan College of Agriculture Udaipur.

Histopathological changes in maize roots were studied when inoculatedwith the maize cyst nematode, Heterodera zeae. Second stage larvae mostlyoriented parallel to longitudinal axis in the cortex and moved intracellularly asindicated by broken cell walls posterior to the nematode. Cell walls surroundingnematode were dissolved to from a funnel and multinucleate condition was obser

ved indicating early stages in syncytial formation. Enlarged cells bordered bydarkened and thickened cell walls and hypertrophy of cortical, pericycle and endo

c.termalcells resulting in giant cells were observed. Nematode presence accounted


for active cell division. Nematodes, mostly oriented in cortex, had heads thrustin stele and formed large, multinucleate syncytial cells with dense granularcytoplasm. Nematodes enlarged forming necrotic area near feeding sites andfinally pushed the cortical cells to sides, resulting in complete mechanical injury.

PATHOGENICITY OF XIPHINEMA INSIGNE ON VIT/S VINIFERA : ArjunLal, V. K. Mathur, K. C. Sanwal and R. V. Singh, National Bureau of PlantGenetic Resources, New Delhi-ll002.

Pathogenicity of Xiphinema insigne Loos, 1949 on Vitis vinifera cv.

Anabeshahi was investigated by inoculating 50,500 and 5,000 nematodes per plantand comparing the results with those· of control and associated control on microorganisms. Symptoms of nematcde damage like yellowing of leaves, generalstunting and poor growth of plants, swelling of root tips and reduction in number of rootlets were observed in incculated plants. Significant reduction in mainshoot height, fresh and dry root and shoot weights, leaf area and leaf numberper plant was recorded in inoculated plants.

ON THE MECHANISM OF RESISTANCE IN WHEAT AND BARLEY

AGAINST HETERODERA A VENAE: Gopal Swarup and D.R. Dasgupta,Division of Nematology, Indian Agricultural, Research Institute, New Delhi-12.

Studies on the mechanism of resistance to cyst-forming nematode,Heterodera avenae were made in 3 vars. of wheat (viz. Kalyan Sona, cv Festiguayand Aus 10894 x Olympic) and 4 vars. of barley (viz. BP 263, BP 264, C 164 andRatna). Initial observations on penetration of larvae revealed that the nematodespenetrated in an the varieties tested, although in varied numbers. However,subsequent to their penetration, only few cysts developed in wheat var. cv Festiguay and barley vars. BP 263 and C 164. No cysts were observed in barley var.BP 264. There was a corresponding decrease in cyst contents in all these varieties which are judged to be resistant to the nematode. Alteration on proteinsand enzyme proteins was remarkable in nematode infested materials. Increasein the concentration of proteins as well as peroxidase activities were recorded innematode-infested plants, the increase being more in resistant than susceptiblevarieties. Barley vars. BP 263 and C 164, resistant plants to the neatode reSponded to parasitic invasion by synthesizing two additional anionic proteins bands


/

having different electrophoretic mobility. The newly synthesized proteins wereidentified as peroxidase components and judged to be significant in relation toresistant responses.

ON THE BIOCHEMICAL MECHANISM OF RESISTANCE IN TOMATO

AGAINST THE ROOT-KNOT NEMATODE, MELOlDOGYNE INCOGNITA: D. R. Dasgupta, T. N. A. Farooqi, A. K. Ganguly, U. N. Mote,Sudershan Ganguly and D. Premachandran, Division ot Nematology, IndianAgricultural Research Institute, New Delhi-12.

Basic studies relating to biochemical mechanism of resistance in tomato tothe root-knot nematode, M. incognita were made to elucidate biochemical basisof resistance in hosts to the nematode. Enzymic regulation of phenylpropanoidpathway leading to biosynthesis of certain benzoid compounds during postinfection period of hosts varied significantly in the resistant-reacting and susceptible tomato varieties. Our studies indicated that the nematode mediated disease

resistance in tomato var. SL-120 was due to inducible production of antibioticmolecules. The initial biochemical events which occurred soon after nematode

infection of host plants leading to resistance responses was mediated by de novogene activation, and thereby resulting in the synthesis of new species mRNAS andenzyme proteins possibly required for the production of antibiotic molecules.The results of this investigation lead us to suggest that interactions between thehosts and the parasite resulted in a rapid alteration of host metabolism at thegene transcriptional level.

PATHOGENICITY STUDIES WITH MELOlDOGYNE INCOGNITA ANDROTYLENCHULUS RENIFORMIS ON TWO VARIETIES OF GRAPE

VINE: K. Tirumala Rao and A. R. Seshadri, Department of ~ntomology,A. P. Agril. University, Agricultural College, Bapatla.

Eight Pathogenicity experiments, four on M. incognita and four on R.reniformis were conducted. These studies revealed that 10 days old seedlings ofgrape (Anab-E-Shahi) were killed by M. incognita within 30 days of inoculationwith an initial population level of 1000 nematodes per pot (500 g soil) and above,while 1,00,000 larvae of Rotylenchulus reniformis were able to kill only 3 plants

out of7. No death was observed in seedlings of 60 days and above and also incuttings of 4 months age. Inoculations on 60 days old seedlings at 90 days after


inoculation showed more damage by 1000 level of nematodes than 10,000 levelin both the nematodes.

PATHOGENICTY OF PRATYLENCHUSDELATTREI LUC, 1958 TO CROSSANDRA WITH SPECIAL REFERENCE TO BIOCHEMICAL ALTERA

nONS: Sivagami Vadivelu and T. S. Muthukrishnan, Tamilnadu Agricultural University, Coimbatore-64l 003.

Pratylenchus delattrei Luc, 1958 is one of the important plant parasiticnematodes in Tamilnadu, particularly on Crossandra, an ornamental crop whichis cultivated,in several parts of the State. The observations made on the effectof higher levels of nematode population on plant growth and their effect on majorand minor elements, carbohydrate level in the leaves and free sugars, amino acids,peroxidase and B-glucosidase activity and phenolic content of roots are presentedin the paper. The plants inoculated with 1000 and 5000 nematodes at the timeof planting exhibited foliage discolouration and chlorotic symptoms in 35-40 daysand 20-27 days respectively. Reduction in shoot length, shoot weight, root lengthand root weight 'and the total number of roots in the infected plants (22.7-47.1,80.0-95.4; 65.1-93.1, 84.9-97.8 and 69.1-92.6 per cent respectively) was also noticed.The plants treated with 5000 nematodes failed to produce the flower spikes, whilethose inoculated with 1000 nematodes produc~d 1.7 spikes and 25 flowers perplant in contrast to 9 spikes and a total 104 flowers developed in healthy plants.The leaves of the nematode infected plants exhibited deficiency in nitrogen (22.459.0% and increase in phosphorus and potassium (11.5-45.4 and 70.0-137.3%).

Among the micronutrient elements, increase in zinc (8.8 and 42.5 per cent) andcopper (66.0 and 108 percen,t) and decrease in the iron (12.0 and 24.0 per cent) andmanganese (24.2 and 36.8 per cent) content were noticed in the leaves. A reduction of 30 and 15 per cent in the carbohydrate was also noted. The details ontotal free sugars, the total amino acid and the orthodihydroxyand total phenoliccontents of the nematode inoculated plant roots are also furnished.

INFLUENCE OF DIFFERENT SOURCES OF NITROGEN ON THE ROOTNEMNfODE BUILD UP IN RELA nON TO BIOCHEMICAL CHANGES

IN THE RICE ROOTS: J. S. Pr asad and Y. S. Rao, Central Rice ResearchInstitue, Cuttack-6.

The effect of organic and inorganic sources on the building of the rootnematode, Hirschmanniella mucronata and changes in total phenols and nitrogen


levels were studies in rice var. IR. 8. The organic fertilizers viz., Ammoniumsulphate, urea and Cal. ammonium nitrate and inorganic fertilizers viz., Azolla,Water hycinth, Ipomea, FYM, Biogas affiuent and cattle shed washings were givento make 60 kg/ha in 4 replications. Samples were collected 50 days after treatment and analysed for nematodes, nitrogen and total phenols. Maximum buildup was observed in cattleshed washings treatment followed by treatments withIpomea, Biogas affiuent and FYM in which high amountS of nitrogen and low totalphenol contents were recorded comparatively to the other treatments.

MELOIDOGYNE INFECTIONS IN SUSCEPTIBLE HOSTS - A METABOLIC

QUANTITATION : S. Kannan and T. Chandraguru, Dept. of Zo010gy,Thiagarajar College, Madurai - 625 009.

In host plants susceptible to Meloidogyne infections, susceptibility beingthe common factor the degrees of susceptibility reflect the individuality. Thisindividuality centres around the differential mobilization of metabolites, viz.differences in catalysis and synthesis etc., attendant with the pathologicalmetabolism.

Two susceptible hosts viz. cowpea (Vigna sinensis) and beans - (Dolichoslablab)infected with 500 juveniles. of M. incognita acrita were analysed for thevarious metaboli tes, 30 and 60 days after inoculations by adopting the standardpwcedures.

The two different susceptjble hosts, exhibited" different rates of turn over ofthe metabolites studied. The shoot system (area remote from the site of infestation)and the galls (site of infestation), seemed to behave independent of each otherindicating localized reactions.

Taking Cowpea as an example, sugar depletion in the gall on the 30th daywas greater than on the 60th day. The shoot registered lesser drop. Proteinbuild up was extensive in the gall indicative of significant synthesis. This was alsoindicated for the phenols on the 30th day, but on the 60th day, phenols depleted,indicating their differential turn over as infection progressed. The shoot on thecontrary registered increments for phenols. The lipids which reduced on the 30thday, registered increments on the 60th day, again, reflecting their differentialmobilization, as infestation progressed. The shoots on the contrary, registereddrop on both the occasions (30th, 60th days.).

Similarly, infested beans also exhibited differential mobilization of thevarious metabolites, at different intervals in the different areas.


Quantitatively the picture of the pathological metabolism for the hosts,was as follows:

Cowpea:

While catalysis amounted to nearly 75%, synthesis amounted to 1/3rd ofcatalysis in the root on the 30th day. In the shoot also, synthesis was almostl/3rd of catalysis on the 30th day. Amidst different mobilizations of the variousmetabolites, the shoot and the root seemed to put up almost an uniform rate ofsynthesis on the 30th day of infestation. On the 60th day, synthesis in the rootamounted to almost four times that of catalysis in the gall, while in the shoot,it was nearly five times that of catalysis.

Beans:

In the gall synthesis was only ith that of catalysis on the 30th day while inthe shoot it was only 1/7th of catalysis. The two regions thus markedly variedin their metabolic turn over on the 30th day. On the 60th day, in the gall, synthesis was almost 1.5 times that of catalysis in the gall while in the shoot it wasnearly 2.75 times greater than catalysis.

Thus it is seen that, the individual hypersensitive reactions are different, inthe two susceptible hosts.

EFFECT OF HIRSCHMANNIELLA ORYZAE INFESTATION ON RICE:

K. John Kuriyan and M. S. Sheela, College of Agriculture, Vellayani.

The extent of damage done by H. oryzae on rice plant and its yield wasevaluated by a field trial. Rice variety, Jaya was grown with natural populationof H. oryzae, five fold increase over natural population, ten fold increase overnatural population, natural population and soil treated with carbofuran @

1 kg/ha, at seven and fifty days after planting.

There W;lS significant reduction of 6.2 to 13.8% in the number of productive tillers; 3.9 to 9.6% in height of shoot; 17.1 to 29.9% in weight of shoot14.5 to 38.8~/~ in the weight of shoot; 4.0 to 8.0% in the length of panicle 7.9 to20.5 in the weight of panicle and 7.9 to 22.5% in the weight of grains per plantby the infestation of H. oryzae, over the natural population in soil. The carbofurantreated plants showed an increase of 9.2,3.3, 14.0,26.1,4.92, 1.7 and 16.9% respectively for the above characters. The dry grain weight and straw weigh per plot of12 sq.m. were also reduced by 12.7 to 45.0% and 11.6 to 28.8% respectively by H.


oryzae over the normal population. But the carbofuran treated plants had an increase of 17.9 and 14.6% in dry grain weight and s'traw weight. When the soil androot population increased significantly in the nematodes inoculated treatments, theywere significantly reduced in carbofuran treated plots. Thus the improvementin plant characters with increase in yield in carbofuran treated plants could beattributed to the reduction in soil and root population of H. oryzae and thereduction in plant characters with reduction in yield, due to increase in nematodepopulation. There was a significant negative correlation ( -0.93 ) between nematode population in root and grain yield and ( -0.94) between nematode populationin the root and number of productive tillers or earheads.

DAMAGE CAUSED BY MELOIDOGYNE INCOGNITA ON BRINJAL :

Susannamma Kurien and K. John Kuriyan, College of Agriculture,Vellayani.

The nature and extent of damage caused by root-knot nematode, M. incognitato brinjal at different inoculum levels of 10, 100, 500, 1000, 5000 and 10,000 larvaeper plant was studied, in pot culture.

There was a significant reduction of 14.8 to 64.6% in number of leaves;4.9 to 32.6% in shoot length; 5.9 to 61.2% in weight of shoot; 5.2 to 34.9% inwight of root; 20.9 to 82.1% in yield and 21.1 to 89.1 '};,in mean weight of brinjal,by the different inoculum levels of the root-knot nematode, within 108 days ofinoculation. The total number of root-knots present in each plant increased from148.5 at the inoculum level of 10 to 412.3 at the inoculum level of 10,000 larvae.The soil population of M. incognita also increased from 28.0 to 243 per 100 ml ofsoil. It may be infered that M. incognita is positively involved in the unthriftygrowth of the brinjal plant and the consequent reduction in yield.

FIRST REPORT OF PARASITILENCHUS COCCINELLAE IMPERTI ANDWAEREBEKE (1968) FROM INDIA IN TWO NEW HOSTS OF MENOCHILUS SEXMACULATUS (F) AND ILLEIS INDICA TIMB. : P. NarayanRao and Y. Narsi Reddy, Dept. of Zoology, University College of Science,Hyderabad-7.

Parasitylenchus coccinellae Imperti and Waerebeke, 1968 was found toparasitise the hosts Menochilus sexmaculatus (F) and Illeis indica Timb (Coleo

ptera : Coccinellidae). The biology and life history has been. studied. InfectionwaS found neither in grubs nor in pupae but only in the adult aphidophagous


beetles. More than one generation of the nematode was found in the host hemocoel. The study of morphology of different stages revealed slight differences inthe Indian forms compared to Waerebeke and Imperti (1968) forms. The impregnated females and males had bifurcated tail tips, besides differences in dimensions.Due to heavy infection and number of generations in the hosts there was damageto the internal organs of the insect reproductive system.

ON OCCURRENCE OF NEMATODES IN THE UPPER GANGES CANAL

IN UTTAR PRADESH: M. I. S. Waliullah, Department of Zoology,Aligarh Muslim University, Aligarh- 1.

In order to investigate the occurrence of nematodes in the irrigation waterin Uttar Pradesh, India, a survey of the Upper Ganges canal was conducted fromOctober 1978 to December 1979. The irrigation water was found to contain from1 to 5 nematodes per litre of water. Nematodes found in the canal included,among others, representatives of orders Tylenchida and Dorylaimida. The tylenchid nematodes were about 12-35% of the total population. Species of thetylenchid genera, Tylenchus Bastian, 1865; Tylenchorhynchus Cobb, 1913; He/icotylenchus Steiner, 1945; Rotylenchus Filipjev, 1936; Basiria Siddiqi, 1959; Basirolaimus Shamsi, 1979; Aphelenchus Bastian, 1865; Sakia Khan, 1964; Hemicriconemodies Chitwood & Birchfield, 1957; Quinisulcius Siddiqi, 1971; were observedbesides specimens which obviously belong to a new genus which is being publishedelsewhere. The dorylaims, which were approximately 20-51.4% of the totalpopulation, included species of the genera Longidorus (Micoletzky, 1922) Filipjev,1934; Xiphinema Cobb, 1913; Dorylaimus Dujardin, 1845. Enchode/us Thorne,1939; Trichodorus Cobb, 1913; and Mylonchulus (Cobb, 1916) Pennak, 1953. Thetotal population of nematodes was relatively high during July-September 1979.During this period the number of tylenchid nematodes was also high. The totalpopulation of nematodes including that of tylenchids was found to be highestduring September 1979, with the former and the latter reaching 137 and 58nematodes per 30 liters of water respectively.

DISTRIBUTION OF PHYTONEMATODES ASSOCIATED WITH CITRUS:

P. P. S. Baghel and D. S. Bhatti, Department of Nematology, HaryanaAgricultural University, Hissar.

Distribution of phytonematodes in soil around the roots of citrus plants attwo horizontal spacings (30 and 90 cm from tree trunk) and at two vertical depths


(0-15 and 15-30 cm) at monthly intervals for a period of two years was studied.Maximum nematode population/250g soil was recorded in April and October. Theplant-parasitic nematodes were observed to increase from March to April andSeptember to October. Relatively, larger number of nematodes were recoveredat 30 than 90 cm distance from tree trunk at both the depths. Populations registered at 0-15 cm was slightly higher than 15-30 cm at both the horizontaldistances. A similar trend as that of total nematode population was noticed forthe population of Tylenchulus semipenetrans in the soil and roots. Numbers of3rd and 4th stage larvae of this nematode were hi,3'hest in October and lowestin February. Higher numbers of this nematode in April and October appears tobe due to the prevalence of conducive conditions for its multiplication and availability of sufficient fresh roots in these months. Populations of Xiphinema insigni,

He/icotylenchus dihystera and Pratylenchus pratensis increased considerablyfrom October to December. Hoplolaimus indicus population showed increasefrom April to July. This rise in the populations of these nematodes may beasc'ibed to the favourable temperature and moisture conditions.

NOTES ON THE SYSTEMATIC POSITION OF THE GENUS NYGELLUS

THORNE, 1939. : Maqsood Ahmad and M. Shamim Jairajpuri, Section ofNematology, Department of Zoology, Aligarh Muslim University,Aligar h-202001.

The genus Nyge//us Thorne, 1939 is distinct among all dorlyaim nematodesas it shares the characters of the super-families Nygolaimoidea De Coninck, 1965(possession of a mural tooth) and Belondiroidea Thorne, 1964 (possession ofspiral muscle sheath). Thorne (1939) placed this genus under the family Belondiridae while Jairajpuri (1964) proposed a separate family Nygellidae for its reception. Since then, the position of this peculiar nematode has remained controversial. Thorne (1964), Siddiqi (1968), Ferris (1971) included Nyge//us as wellas the family NygeIlidae under Belondiroidea while Heyns (1968) and Andrassy(1976) considered it under Nygolaimoidea. Recently, Jairajpuri & Ahmad (1980)did not include it under Belondiroidea. The genus at present includes only threespecies and all these possess a mural tooth, cardiac glands at base of oesephagusand spiral muscle sheath around the basal expanded portion of oesophagus. Studyof a large number of specimens of Nyge//us c/avatus Thorne, 1939 collected fromJorhat (Assam) revealed the definite presence of a spiral muscle sheath around theexpanded portion of oesophagus though the sheath is not very conspicuous. We,therefore, suggest that this genus be included under the superfamily Nygolaimoidea


of the suborder Nygolaimina Ahmad & Jairajpuri, 1979 because of the presenceof mural tooth and the cardiac glands, both of which are characters of fundamental importance in dorylaim systematics. The presence of spiral muscle sheathhas already been reported in some other genera outside Belondiroidea as alsopointed by Jairajpuri & Ahmad (1980).

PREVALENCE AND INTENSITY OF NEMATODE INFESTATION IN TEAPLANTATIONS OF WEST BENGAL: B. Mukherjee and M.K. Dasgupta,Plant Pathology Laboratory, College of Agriculture, Visva-Bharati University, Sriniketan-731236, W.B.

Analysis of 120 soil and root samples collected from five widely distributedtea estates and plantations in Darjeeling District, West Bengal showed presenceof nineteen species of plant parasitic nematodes belonging to thirteen genera ofwhich sixteen were hitherto unknown in West Bengal. Intensity of nematodeinfestation was compared and analysed by relative frequency, relative populationdensity and prominence value of the nematode species at different locations.Nematode densities varIed greatly with plantations, ranging from less than 10 tomore than 950 nematodes per 250 ml soil. Helicotylenchus dihystera ranked firstin mean population density/site and prominence value, although it was lessfrequent as compared to other nematode species. Helicotylenchus spp., Pratylenchus loosi and Macroposthonia ornata were also considered plOminent in thesetea plantations. Pratylenchus loosi, Paratylenchus lepidus, Atlantodorus porosus,Aglechus agricola, Coslenchus spp, have been found to be associated with teafor the first time from India. All species are new with respect to geographicaldistribution.

PROTRELLATUS SP. FROM THE COMMON HOUSE CRICKET, GRYLLUSDOMESTICUS: K. Vijayalakshmi and E. Khan, Division of Nematology,Indian Agricultural Research Institute New Delhi-l2.

Nematodes belonging to genus Protrellatus Farooqui, 1970 were foundparasitising the common huose cricket, Gryllus domesticus. The crickets werecollected from stacked earthen pots in the Division of Nematology, Indian Agricultural Research Institute, New Delhi and dissected in 1% Nacl solution. Thenematodes (females and juveniles) were present in the intestinal region of the host.The incidence of infestation was quite high 1 to 8 nematodes in 80% crickets.


When only a single female was found in a host, it occupied almost the entirewidth of the intestine. The nematode differs from the only existing species ofthe genus, P,alli Farooqui, 1970 and hence suspected to be new.

OCCURRENCE OF RADOPHOLUS SIMILIS (COBB, 1893) THORNE, 1949 INGUJARA T, INDIA: C. L. Sethi, Siya Nand and A. N. Srivastava, Divisionof Nematology, Indian Agricultural Research Intstitute New Delhi-12.

In India, burrowing nematode (Radophoius similis) was reported frombanana (Nair et al., 1966) and coconut (Weischer, 1967). Koshy et al. (1978)reported its wide spread occurrence on banana, arecanut, coconut and pepper inKerala. So far this nematode has been found to be confined to southern statesof Kerala, Karnatka, Tamilnadu and Andhra Pradesh (Koshy and Nair, 1979).During a preliminary survey of plant parasitic nematode associated with bananain Navsari and adjoining areas of Gujarat, Radopholus similis was rocovered inthe soil as well as in the root samples collected from the farm of College ofAgriculture, Navsari. Quite a few females were present in the sample but thenumber of males was less. The light infestation was suggestive of the fact theintroduction of Radopholus similis in Gujarat along with the planting materal isrecent.

The measurements of Gujarat population are as bellow:

5 females: Length = 626-696 I-'m, spear = 18-20 I-'m,

a = 26.07-34.7; b = 5.7-7.5; b' = 3.6-5.6;c = 9.2-11.4; V = 57-58.8

2 males: Length ~ 560-608 I-'m, spear = 16-19 I-'m,

a = 30.4-32.8; b = 7.0-7.2; b' = 4.1-4.6;c = 9.03-9.2,

NE MA TODES ASSOCIATED WITH FODDER CROPS IN A COCONUT

GARDEN : P. Sundararaju, Nematology Laboratory, Central PlantationCrops Research Institute, Regional Station, Krishnapuram-690 533, Kayangulam, Kerala.

A study was conducted to find out the effect of various fodder crops suchas Stylo (Stylosanthes gracilis), Pusa Giant Napier, NB-21, and Guinea grass


(Makueni) on the population build up of the nematode fauna in a sandy loam area.Samples were drawn in August, 1979, July and October, 1980. These crops werefound to have no significant effect on the population build up of nematodes oncoconut, Radopholus simi/is was recorded only from coconut roots whereasPratylenchus zeae was recorded from roots of all fodder crops but not fromcoconut. Tylenchorhynchus cofJeae was occasionally recorded from coconut roots.In general the following nematode species viz. Aphelenchoides sp., Aphelenchus(Anaphelenchus) isomerus, Ditylenchus sp., Cricollemoides sp., Helicotylenchusabunaamai, Hemicriconemoides brachyurus, Hoplolaimus seinhorsti, LOllgidorussaginus, Meloidogyne sp., Pratylenchus zeae, Paratrichodorus acaudatus, Rotylen- .chulus reniformis, Tylenchorhynchus cojleae and Xiphinema elongatum were recordedfrom all the treatments in small numbers.

REPORT ON THE OCCURRENCE OF NOTHANGUINA PHYLLOBIA

(THORNE,1934) WHITEHEAD, 1959 IN TAMIL NADU AND SOMEOBSERVATIONS ON ITS BIOLOGY: C. V. Sivakumar and M. Mohana

sundaram, Tamilnadu Agricultural University, Coimbatore-641 003.

The foHar nematode Nothanguina phyllobia was first noticed in a smallpocket in Coimbatore town, during May, 1979, causing galls on the leaves of theweed Solanum elaegnifolium Cav. Field observations showed that the leaf gallsappeared after rainfall. The plants growing along ditches and shady situationsgenerally had severe infestation of the nematode. No other weed, growing alongwith the affected plants, was infected. The affected leaves had a population of19,533 and 25,565 nematodes/g, during the months of May and November,1980, respectively. Laboratory experiments showed that the nematode survivedunder desiccation over anhydrous calcium chloride for over 7 months in leaf tissue.The nematode was highly tolerent to heat and survived for over 7 moths under atemperature of 40± 1°C.

STUDIES ON THE EXTENT OF VARIATION IN HOPLOLAIMUS INDICUS

SHER, 1963 I. MORPHOLOGICAL CHARACTERS: M. L. Chawla andS. M. Yadav, Division of Nematology, Indian Agricultural ResearchInstitute New Delhi-l2.

Most of the presently described nematode species being phenetic, availa

bility of information on the morphological variability within any specjes is of


paramount importance for authenticity in taxonomy. Therefore, all the 14 (25,including sub-categories) characters of 460 topotypes (plus 100 topotypes usedfor en face views) were studied and observations recorded. An additional numbet"(560) of specimens collected from four different hosts (sugarcane, sorghum,citrus and banana) each from four localities (Hissar Narnaul, Udaipur and Delhi)was also studied. These too, were found to fall within the range of morphological variations of topotypes. The variations are as ander :

1. Body shape: The body was generally stightly to more ventrally curvedbut many other (open C, closed C, Jay, hook, open spiral and even closed spiral)curvatures also appeared.

2. Lip region: The lip region varied in shape; sclerotization (very lightto heavy); demarcation (rarely continuous to generally distinctly set-off) numberof annules on head (smooth to 5 or 6 annules); furcation of radial arms of cephalic sclerotization (bi, tri or tetrafurcate dorsal and ventral arms and (2 to 21 lobeden-face view depending on the same number of longitudinal striations on basalannule.

3. Cephalids: The anterior and posterior cephalids may be located 2-4annules behind head and conus-shaft junction of spear in few cases (normal position is 0-1 annule behind head and in level with conus-shaft juction respectively).

4. Lateral field: Lateral field with none to 1, 2, 3 or 4 incomplete,small and superficial incisures not visible as grooves in transverse body sections;or generally only as breaks in tranverse striations of totomounts.

5.. Phasmids: Phasmids 2-5um in diameter, anterior 23-46% while posterior65-95%, either of them may be right or left; double anterior and/or posteriorphasrnids were also observed in 3 specimens. Two specimens revealed 5 phasmidseach.

6. Excretory pore: Excretory pore may by located any where from 'inlevel with anterior. end of the valves of median bulb to about a body widthposterior to oesophago-intestinal valve. Two excretory pores with distinct ductswere seen in a specimen.

7. Hemizonid and hemizonion: Hemizonid differed in. location from 'atlevel with excretory pore to 26 annules behind it. A specimen had second hemizonid 25 annules above excretory pore. Hemizonions may be more than 1 (upto3), located one to 35 annules behind hemizonid.

8. Spear: Spear knobs may have 1, 2 or 3 anterior projections and thuswi th irregular anterior surfaces.

9. Oesophagus: Oesophagus with 4 dorsal gland nuclei and 1 subventralin same plane, the 6th-that of the other subventral in slightly different plane-total 6

••


nuclei. Coefficient of gland overlap =24-76%. Median bulb generally round,well set-off, may sometimes become slightly to more ovoid, not well set-off fromprocorpus.

10. Rectal overlap of intestine: In most of the topotypes, an extensionof the intestine went beyond the recto-intestinal junction but the length of thispost-rectal overlap varied from a condition hard to interpret between "present orabsent" to the one where almost entire tail was occupied by intestinalextension.

11. Spermatheca: In many specimens the spermatheca was not visiblebut in some it was very distinct (perfectly spherical to ovoid). The frequency ofsuccess for locating spermatheca differed from population to population. Generallyspeaking, it was more where males were more abundant.

12. Tail: Both the'shape and the number of annules varied considerably.The tail shape varied lesser within males but in females it departed in 15% of thespecimens from the normal rounded shape showing that the departures from thetypical shape were not rare. Such variations could broadly be classified as :-

a) narrowing towards tip,

b) dorsally, convex, ventrally flattened,

c) dorsally flattish but ventrally convex,

d) notched dorsally, superficially moderately, deeply or very deeply,

e) notched ventrally superficially, moderately, deeply or very deeply, and

f) notched terminally superficially, moderately, deeply or very deeply.

The number of tail annules langed from 7 to 22 and the annulation alwaysextended upto its tip. However, the distinctness of caudal annulation varied

considerably, becoming inconspicuous in occasional specimens. In some of thespecimens some of the annules in region of the tail tip had almost double thewidth of adjacent annules. number of annules countable on dorsal side was notnecessarily equal to those on the ventral side. Counting of tip annules wassometimes difficult due to fusion of annules and/or notching of the tail.

13. Caudalids: Caudalids (not seen by Sher) differed in position from10 annules anterior to anus to 9 annules posterior to anus.

14. Epiptygma: Epiptygma may be completely absent; single anterior/posterior or double (anterior and posterior).


STUDY OF CORRELATION COEFFICIE'NTS BETWEEN MORPHOMETRIC

CHARACTERS OF HOPLOLAIMUS INDICUS SHER, 1963: M.L Chawlaand S. M. Yadav, Division of Nematology, Indian Agricultural ResearchInstitute New Delhi-12.

Absolute measurement of 1020 specimens (460 Topotypes and 560 specimens from other hosts and localiii~s)\ of H. indicus Sher, 1963 were used for thisstudy. These specimens were collected from four (sugarcane, sorghum citrus andbanana) from each of the five different localities (Karnal, Hissar, Narnaul, Udaipur and Delhi) in order to test the effect of host and/or locality on correlationcoefficient between any pair of characters.

Data for 12 different characters of females were computed to obtaincorrelation matrices giving correlation coefficients between all 78 and 66 combinations of characters for females and males respectively for every host andlocality. -It was found that:

(a) No constant correlation exists between any two characters other thanthe body length upto vulva and length upto anus. The correlation between prevulval and pre-anal body lengths varied lesser (0.8082-0.9495) than between anyof these alone and the body leJ1gth (0.6496-0.9484 and 0.8036-0.9999 respectively).

(b) The correlation coefficients between any two characters differ withthe (1) host (2) locality (3) ,character under consideration and (4) sex.

(c) Since there is no constant correlation between any of the measurements used to calculate the ratios a, a', b, b', c and c', these ratios have littlemeaning.

SUSCEPTIBILITY OF CERTAIN VARIETIES OF CLUSTER BEAN TO THE

ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA : A. C. Verma,A. K. Pathak and B. S. Yadav, Department of Nematology, RajasthanCollege of Agriculture, Udaipur, Rajasthan.

Thirty four varieties of cluster bean (Cyamopsis tetragonaloba) werescreened and none was found immune or resistant. Among fourteen varietieswhich were found tolerant (gall index 3.0 and 2 to 15 galls per plant), RGC-760had only two galls and two egg masses per plant. Moderately susceptible varieties were six in number (3.4 gall index and 16 to 20-5 galls per plant). Remainingvarieties were susceptible to highly susceptible (gall index of 3.6 and galls rangingfrom 21.5 to 45 per plants).


EFFECT OF SOME INDIGENOUS PLANT MATERIALS AND OIL-CAKEAMENDED SOIL ON THE GROWTH OF TOMATO AND ROOT-KNOT

NEMATODE POPULA nON : B. K. Goswami and K. Vijaylakshmi,Division of Nematology, Indian Agricultural Research Institute NewDelhi-12.

Applications for both soil organic amendments and dry products of certainindigenous plants which are known to possess nematicidal properties have receivedattention in the recent years for the control of plant parasitic nematodes. In thepresent study the efficacy of ten dried plant materials viz., Ec/ipta alba, Canabis

sativa, Chenopodium amaranticolor, Atropa belladonna Amaranthus sp., (wholeplant) Calotropis gigantea, Ricinus communis, Datura metch, Mangifera indica

and Azadirechta indica (leaves only) and five oil cakes, Carthamus tinctorius,

Shorea robusta, Calophyllum inophyllum, Pongamia glabra and Azadirechta indica

were tested against root-knot· nematode on tomato. Each of the dried plantmaterial and cake was ground to fine power and tests conducted in 10 Cm plasticpots. Three dosages were selected after the preliminary trial for each soil amendment. For every dosage, six replications were maintained out of which three wereinoculated with 1000 larvae of Meloidogyne incognita per pot while the other threewere left uninoculated as checks. Besides, adequate checks were also kept withoutany amendments. Observations were recorded on plant growth characters,nematode populations (both in roots and in soil) as also of the rhizosphere fungiof each treatment. Among plant materials, Eclipta alba was most effectivefollowed by Azadirechta indica, Datura metch and Amarantus sp. in reducing rootknot galls while Cannabis sativa, Ricinus communis and Calotropis gigantea alsoshowed a high inhibition of nematode population. Length and weight of tomatoplants in respense to above materials also significantly increased in comparisionto infested control. In case of cakes, Shorea robusta, Pongamia glabra, Azadire

chta indica and Carthamus tinctorius reduced galls as well as nematodes in soilwhile Calophyl/um inophyllum did not reduce the gall number but inhibitednematode population. The results thus indicated that all the plant extracts andcakes tested possess nematicidal properties.

CHEMICAL CONTROL OF PHYTONEMATODES OF GRAPEVINE (VITlS

VINIFERA): P.P.S. Baghel and· D.S. Bhatti, Depar'tmentof NematologyHaryana Agricultural University, Hissar.

Four chemicals, viz. aldicarb (Temik IO-G), carbofuran (Furadan 3-.G),fensulfothion (Dasanit 5-G), and phorate (Thimet 10-G) each @ 2, 4 and 6 kg


. a.i./ha were applied in basin area of nematode-infested grapevines (var. Perlette)to determine their comparative efficacy. Phytonematodes infesting grapevinesincluded Meloidogyne, Pratylenchus, Helicotylenchus, Longidorus and Xiphinema(940 nematodes/kg soil). Apart from the lowest dose (2kg a.i. /ha) of aldicarb,fensulfothion and phorate and fensulfothion @4 kg a.i./ha, all the doses of different chemicals used registered significant increase in yield over the control.Aldicarb @6 kg a.i./ha was found to increase yield by 26.1 per cent as comparedto control. Highest reduction (71.4%) in nematode popluation was also observedat the highest dose of aldicarb. Production of higher number of Meloidogynemales in soil treated with aldicarb was noticed. A tendency in males to develop

intersexes was also observed, indicating a phenomenon affecting normal develop

ment. Among all these chemicals, aldicarb @ 6 kg a.i./ha appears to be the mosteffective chemical for controlling nematodes associated with grapevines. On thebasis of cost benefit ratio (I :3.6), application of aldicarb @ 6 kg a.i./ha can beadvocated.

IN VITRO TOXICITY OF DBCP TO SOME PHYTOPHAGOUS NEMATODES AND HATCHABILITY OF HETERODERA CAJANI: C. L. Sethiand D. prasad, Division of Namatology, Indian Agricultural ResearchInstitute New Delhi-l2.

Toxicological tests with different concentrations of DBCP and exposure ofPratylenchus zeae, Tylenchorhynchus vulgaris and Hemicriconemoides cocophillusrevealed that the percentage mortality was directly proportional to both concentration and exposure period. There is almost complete kill of all three specieswhen exposed to 160 ppm or more for atleast 24 hours. Using CTP as parameter,T. vulgaris was found to be more susceptible to DBCP exposure as compared toP. zeae and H. coyophillus. Further P. zeae was found to be more susceptible at20°C than at 10° or 30°C. Similarly, larval emergence for cysts of Heteroderacajani was proportionately affected with an increase of DBCP concentration andexposure period. Larval emergence was reduced to 9.5,4.8 and 0.8 per cent in

640 ppm for 2, 4 and 8 days respectively as against 41.0 per cent emergence incheck treat.ment.


VARIETAL RESPONSE OF TAGETES PATULA AND T. ERECTA AGAINST

MELOIDOGYNE INCOGNITA : D. prasad and M. M. Haque, Division ofNematology, Indian Agricultural Research Institute, New Delhi-12.

Ten varieties of Tagetes were tested in 20 cm pots against root-knot incidence. An initial population of 3000 larvae/pot resulted in lowest number of gallsformed on var. White Alaska followed by chrysanthemum apetatus of T. erecta.In general, inoculated plants of both T. erecta and T. patula showed an increasein shoot length as compared to uninoculated check treatments. In spite of heavyto moderate nematode infestation, no reduction in shoot length was recordedamongst the varieties tested.

STUDIES ON SOLANUM VERNEI62-63-3 AND HYBRIDS OF S. VERNEI62-33-3 X KUFRI JYOTI FOR RESISTANCE AGAINST POTATO CYST

NEMA TODES IN NILGIRIS: D. Thangaraju and R. Sundaram, PotatoGolden Nematode Laboratory, State Seed Farm, Vijayanagram, Ootacamund-l.

Solanum Vernei 62-33-3, a hybrid potato clone resistant to Dutch pathotype 'D' received from Holland was subjected to two pot culture and two fieldexperiments with the cyst nematode population of project experimental farm,Vijayanagram, Ootacamund. The other test plants viz S. tuberosum. S. andigenum and S. vernei G. LKS 58-1642-4 were also included in pot culture studies.In potted conditions, 15 to 212 new cysts on S. tuberosum, 48 to 176 cysts onS. andigenum, 41 to 85 cysts on S. vernei and only one in S. vernei 62-33-3 wererecorded. Similar results were obtained in 62-33-3 under field conditions also.From the observations it is inferred that the material tested is resistant to 'D'

pathotype in Nilgiris (now G. pal/ida). Since the above material was found highlysusceptible to late blight, Phytophththora infestans, b:eeding was taken up atC.P.R.1., Simla. The progenies were evaluated for resistance against cyst nematodes. Among them four viz. progenies 10, 14, 21 and 28 showed more resistance. They were tested in 30 populations during 1978-80 and found to betolerant to G. rostochiensis and G. pallida.

STUDIES ON DISINFECTING POTATO SEED TUBERS WITH METHYL

BROMIDE IN NILGIRIS : D. Thangaraju, R. Sundaram and S. Vijayaragavan, Department of Agriculture, Tamil Nadu.

Potato cyst nematodes, Globodera rostochiensis and G. pal/ida are causingconsiderable damage to potato cultivation in Nilgiris. Survey has revealed the


presence of the cyst nematodes in an area of 7000 acres at present. Since theseeds were found to be the main carrier, studies were taken up for disinfecting the

seeds. Fumigation experiments with methyl bromide were conducted from 197780 in mini fumigation chambers. The results revealed that fumigating the infested seed tubers with methyl bromide for 5-6 hours killed the cyst contents. Thetreated tubers were also stored for different weeks and planting was taken up at

weekly intervals for 3 months to know whether there was any adverse effect onthe crop. It was interesting to note that the treated tubers sprouted quickly andno harmful effects were observed during the crop period. This provides an economical and effective quarantine method, preventing further spread of cyst nematodes in Nilgiris.

EFFECT OF AGRONOMICAL PRACTICES AND DD APPLICATION ON

NEMATODE POPULATION AND CROP YIELD : M. M. Haque andD. Prasad, Division of Nematology, Indian Agricultural Research InstituteNew Delhi-12.

Clear fallow, fallow with weeds, one ploughing, two ploughings and threeploughings were compared along with the DD treatment. Effect·of fallow, number of ploughings, DD treatment at the rate of 300 litersjha on nematodepopulation and yield has b~en studied under field conditions. During rabi seasonwheat was sown and mazie was taken for kharif season. All the three ploughingswere found to be superior as compared to plots kept under fallow. Highest totalnematode population was observed in plots under fallow and fallow with weedsand wheat yield was reduced to about four times (2.80 kgs) in comparison to plotswhich received DD treatment (8.40 kgs). Increase in the number of ploughingsresulted in a corresponding decrease of Hoplolaimus indicus, Helicotylenchus sp.,

T)Jlenchorhynchus vulgaris, Pratylenchus zeae and Longidorus sp., and also corresponding increase in corp yield was observed. Almost the same trend was observed in maize crop. Fallow decreased maize yield considerably (3.89 kgs) whereasDD treatment increased the yield (I 1.19 kgs). Nematode population build upwas also maximum in plots which preceded fallow.


I.\

SEED TREATMENT WITH NEMA TICIDES AND FUNGICIDES FOR THECONTROL OF WILT COMPLEX INVOLVING ROTYLENCHULUS RENIFORMIS AND RHIZOCTONIA SOLA NI IN OKRA: S. Kumar and

C. V. Sivakumar, Tamilnadu Agricultural University, Coimbatore-641 003.

The following seed treatments were evaluated for the control of wiltinvolving Rotylenchulus reniformis and Rhizoctonia solani, in glasshouse experiments.

1. Carbofuran 5% (w/w) + Talc 8% as sticker

2. Aldoxycarb 5% (w/w) + starch 2% as sticker3. Carbendazim 0.2%0 (w/w)4. Captafol 0.2% (w/w)5. Control (untreated seeds sown in soil infested with both the pathogens)

6.. Aboslute control (untreated seeds sown in autoclaved soil).

The experiment was conducted in clay pots inoculated with the nematodeand the fungus and compared with an absolute (autoclaved soil).

In control (without seed treatment) the pre-emergence damping off was97.97% but in all the four chemical treatments the wilt incidence was significantlylow, ranging from 9.50 to 27.03%. There was no pre or post-emergence wilting in absoltute control, whereas total wilting was observed in control. Amongthe chemical treatments the post-emergence wilt varied from 3.73 to 8.33:;~andcaptafol gave the best results while the other three chemicals were on par.

Infection by the reniform nematode' was suppressed by both nematicides andfungicides studied but the nema"ticides aldoxycarb and carbofuran were superiorto the two fungicides.

OCCURRENCE OF ROOT-KNOT ON TURMERIC (CURCUMA LONGA L.)AND ITS CHEMICAL CONTROL: D. J. Patel, B. M. Makadia and H. M,Shah, Tobacco Projects, Gujarat Agricultural University, Anand Campus,Anand.

Turmeric (Curcuma longa, L.) Crop grown in the residential area of theGujarat Agricultural University, Anand Campus, Anand during 1978-79 showedstunting and withering. Such plants died prematurely. Examination of the rootsof such plants revealed heavy galling. The rhizomes were much reduced in size.

Microscopic examination revealed the presence of large number of mature females


with egg masses identified as Meloidogyne incognita. Application of DBCP(Nemagon 60 EC) at 15 1 a.i.jha and phenamiphos (Nemacur 5G) at 2.5 kg.a.i.jha. checked the disease and resulted in increased rhizome yield to the tune of360 and 208% respectively. The reduction in the disease was to the extent of44 and 15% respectively.

EFFECT OF REMOVAL OF KNOTTED ROOT PORTION ON THE ESTABLISHMENT AND YIELD OF BIDI TOBACCO: G. J. patel, H. M. Shah,D. J. Patel and G. B. Valand. Tobacco Projects, Gujarat AgriculturalUniversity, Anand Campus, Anand.

During the period of seedling famine, the farmers go for planting evenheavily knotted tobacco seedlings. Such seedlings later on remain stunted and thefarmers suffer heavy loss. To explore the possibility of planting such seedlingsafter the removal of knotted root portions on the development and the yield ofbidi tobacco in general as well as in DBCP treated plots, an experiment was conducted for two years. Heavily as well as moderately knotted seedlings wereselected for the purpose and unclipped as well as seedlings after removal of knottedroot portions were planted. Apparently healthy seedlings served as check. Thesefive types of seedlings were relegated to sub plots while nematicidal treatmentwas allocated to main plots. The results indicated that the use of nematicideimproved the growth of the seedlings and reduced the disease significantly,however, clipping of the knotted roots did not make any substantial impact eitheron seedlings establishment or crop yield. The planting of heavily knotted seedlings results in 44% loss in yield.

ASSESSMENT OF LOSS DUE TO ROOT-KNOT DISEASE IN BIOI TOBACCONURSERY: H.M. Shah, D.J. Patel and G. B. Valand, Tobacco Projects,Gujarat Agricultural University, Anand Campus, Anand.

The reduction in number of transplants as well as total seedlings is observeddue to root-knot disease in bidi tobacco nursery. To estimate this loss, an experiment was conducted from 1978-79 to 1980-81 at the Bidi Tobacco ResearchStation, Gujarat Agricultural University, Anand Campus, Anand. The nematodeswere controlled by rabbing the nursery area during first fortnight of June everyyear followed by immediate application of DBCP (Nemagon 60 EC) at 15 1 a.i./hagiven alongwith irrigation water in 30 cm deep furrows 15 days prior to seeding.


Beds kept untreated served as check. The experiment was conducted in paired(AB BA) desi~n with ten replications. The bed size was 1.2 m x 1.2 m. Tobaccovariety GT 4 was used. The results indicated that root-knot disease could be

reduced to the tune of 74% and loss in terms of number of transplants as well astotal seedlings was 51%.

EFFICACY OF NEMATICIDAL SEED TREATMENT IN THE CONTROL OF. ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA ON MUNG

BEAN VIGNA RADIATA: S.D. Mishra and H.S. Gaur, Division ofNematology, Indian Agriculture Research Institute, New Delhi-12

The efficacy of seed treatment with three nematicides viz., aldicarb sulphone, carbofuran and thimet @ 1, 2 and 3 per cent a.i. (w/w) was studied formungbean in4 sq.m field plots infested with Meloidogyne incognita at initial densityof 5 second stage juveniles per cc of soil. Aldicarb sulphone @ 1 per cent wasfound to be most effective in increasing grain yield. Aldicarb sulphone at 2 and 3per cent and carbofuran and thimet at 3 per cent did cause marked reduction innematode population but failed to cause proportionate increase in yield due tophytotoxic effects and decreased germination percentage.

EFFECT OF NEMATICIDAL SEED TREATMENT ON ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA AND ON RHIZOBIAL INOCULATION ON MUNGBEAN ;. S. D. Mishra and H. S. Gaur, Division ofNematology, Indian Agricultural Research Institute, New Delhi-12.

Effect of seed treatment with four nematicides viz., aldicarb, carbofuran,dasanit and thimet at 0.25, 0.50 and 1.00 per cent a.i. (w/w) WllS studied in theabsence and presence of artificial rhizobial inoculation on mungbean under potconditions with soil initially infested with about 18 second stage Meloidogyneincognita juveniles per cc of soil. Aldicarb, thimet and carbofuran improved thegrowth of infested plants at 0.50 and 1.0% but did not reduce galling. Dasanitat all the three dosages improved plant growth and also caused reduction ingalling. Dasanit at 1% was the best in reducing. root-knot infestation and improving plant growth.

Rhizobial nodulation was reduced by about 75% in the presence of M.incognita. Nematicidal seed treatment also improved nqdulation but not to the


level of non-infested plants. The rhizobial nodulation did not improve plantgrowth in the abse~ce or presence of nematode but in the presence of nematicidalseed treatment rhizobia Iinoculation caused further improvement in growth.

CYST NEMATODE, HETERODERA ORYZICOLA ON RICE IN KERALA.11. CONTROL OF H. ORYZICOLA ON RICE BY SEED TREATMENT:Usha Kumari. Rand K. John Kuriyan, College of Agriculture, Vellayani.

Pot culture experiment on rice was conducted for controlling the cystnematode, H. oryzicola by dibbling the seed direct after treatment with nematicides. The seeds were treated with carbofuran, aldicarb-sulfone, phenamiphos,dibutylaminosulfanyl carbofuran (FMC) and phorate at 0.02% by soaking the seedsin a suspension of each for 12 hours.

The height of the plant increased by J3.17% with phenamiphos, 31.05% withFMC, 26.65% with carbofuran, 22.62% with aldicarb sulfone and 7.58% withthimet. The number of tillers increased by 97.81% with phenamiphos, 83.94% withFMC,79.56% with carbofuran,77.37% with aldicarb-sulforne and 70.07% withthimet. The number of leaves increased by 37.13% with phenamiphos, 36.74%with FMC, 36.61% with carbofuran, 26.91% with aldicarb~sulfone and 24.45%with thimet. The shoot weight and root weight increased by 62.11 al1d ~6,:s2%with phenamiphos, 40.78 and 53.04% with FMC, 27.88 and 4523% with carbofuran, 25.66 and 45.79% with aldicarb-sulfone and 15.67 and 22.61% with thimetrespectively. The yield and grain weight per plant increased by 71.65 and 91.84%with phenamiphos, 49.47· and 65.27% with FMC, 46.65 ~nd 60.67% with carbo

furan, 23.77 and 33.05% with aldicarb sulfone and 22.36 and 29.71% wit~ thimet,respectively. There was also a corresponding decrease in nematode pqpulationand cyst population of 78.26 and 65.63% with phenamiphos, 74.41 and ..59.18%with FMC, 70.57 and 58.14% with carbofuran, 65.55 and 50.12% with aldicarbsulfone and 63.88 and 33.90% with thimet respectively.

Phenamiphos at 0.02~~, was superior over the other nematicides tried, asevidenced by the improvement'of plant growth characters and increase in yield,coupled with reduction in nematode population. The results obtained by theother nematicides under study also were were significantly superior in .comparisonto untreated plants.

ABSTRACT OF PAPERS

INTEGRATED CONTROL OF MELOIDOGYNE INCOGNITA ON'BRINJAL:

K John Kuriyan and M.S. Sheela, College of Agriculture, Vellayani. ., .

The effect of cultural operations and nematicides as nursery treatment andas spot application in the control of root-knot nematodes, M.incognita on brinjalwas studied in a field trial. Normal digging (IOcm), deep digging (20 cm), nurserytreatment of metham sodium @ 25 ml/sq:m. and spot application of aldicarb @ 1 kga.i./ha at the time of transplanting were tried in different combinations.

The growth parameters like number of leaves, height of plants, shoot weightarid root weight showed no significant difference in the main field. However, atfinal harvest of the plants normal digging plus nursery treated seedlings plusaldicarb~applied plants gave a significantly higher number of leaves. Also, deepdigging plus nursery treated seedlings plus aldicarb applied plants gave the highestshoot and root weight of 136.5 g and 16.68 g, respectively.

The yield did not vary significantly between treatments, but normal diggingplus nursery treated seedlings plus. aldicarb applied plants gave the highest yi"eldof 13.63 kg from 25 plants, closely followed by deep digging plus nursery treated

seedJing,.plus no aldicl1rb application, with 13.3 kg from 25 plants.Though the soil nematode population was not significantly different bet

ween treatments, deep digging plus. nursery treated seedI1ngs plus aldicarb appliedplants had the minimum number of root-knots and minimum number of rootpopulation between treatments. This indicates that· deep digging decreases thenematcde population prior to transplanting abd when the seedlings raised fromnematicide treated nursery, are transplanted, there is 'less chance of increase ofn~matodes ..

CHEMICAL CONTROL OF ROOT-KNOT NEMATODE, MELOIDOGYNEINCOGNITA ON BRINJAL BY NURSERY TREATMENT: Susannamma

Kurien and K.John Kuriyan, College of Agriculture, Vellayani.

The effect of nursery treatments on brinjal seedlings and their subsequentperformance in a root-knot nematode infested field was studied with four chemicals, viz. DBCP @ 3ml.a.i./sq.m, metham sodium @ 15,20 & 25ml/sq.m, carbofuran @ 0.2,0.3 & 0.4 g/sq.m. and temik @ 0.2, 0.3 & O.4g/sq.m. Seeds of brinjal(local) were sown in nematicides treated nursery beds. Seedlings were uprooted onthe 30th day after sowing and transplanted in the corresponding plots for eachtreatment in the main field. The performance of these plants were compared.


All the seedlings, except in check, were free of root-knots. There wassignificant increase of 49.2 to 54.4% in number of leaves over check, 10.7 to16.4% in height of plants over check and 36.38 to 39.4% in weight of 25 seedlings,over check. In the main field, plants raised from seedlings treated with carbofuran at O.4gfsq.m, aldicarb at O.4gfsq.m. and metham sodium at 25 mlfsq.m gavesignificantly superior results of characters studied. The number of leavesincreased over check by 101.8% with carbofuran @ O.4gfsq.m, 69.3% with aldicarb @O.4gfsq.m. and 68.5% with metham sodium@ 25 mlfsq.m. There was anincrease of 60.4% shoot weight with carbofuran @0.4gfsq.m., 51.1% with aldicarb

@ O.4gfsq.m and 47.8% with metham sodium @ 25ml/sq.m., over check. Theroot weight also significantly increased by 43.8% with carbofuran @O.4gfsq.m.,40.4% with aldicarb @ O.4gfsq.m and 37.4~~ with metham sodium @ 25 ml/sq.m.over the check plants. The number of fruits and weight of fruits were incereasedby 84.0~~ and 66.9% with carbofuran @ O.4gfsq.m., 63.9 % and 97.2% with aldicarb @O.4gfsq.m. and 69.5% and 68.7% with metham sodium @ 25mlfsq.m.

The total number of galls in each plant was reduced by 71.2% withcarbofuran @O.4gfsq.m., 68.4% with aldicarb @O.4gfsq.m. and 57.4% withmetham sodium @25ml/sq.m. Soil population of plant parasitic nematodes including M. incognita was also found to be reduced by 20.0 to 50.1 % in nematicidetreated plants over the check.

EVALUATION OF SYSTEMIC CHEMICALS FOR THE CONTROL OFROTYLENCHULUS RENIFORMIS ON PAPAYA: G. Rajendran andT. G. Naganathan, All India Coordinated Fruit Improvement Project,Tamilnadu Agricultural University, Coimbatore-641 003, India.

The reniform nematode Rotylenchulus reniformis was found highly pathogenic to papaya in India and Hawaii and responsible for papaya decline }n Hawaii.There is meagre information on the control of this nematode in papaya withsystemic nematicides. Investigations ~ere carried out to evaluate the systemicchemicals for the control of this nematode and it was found that carbofuran at

the rate of 2 Kg a.i.fha significantly increased the yield by 38.4% over the control,closely followed by aldicarb sulfone and aldicarb. It was also observed that there

was significant reduction in soil nematode population six months after the treatment compared to pre-treatment population in field condition. Pot culturestudies also revealed that there was significant reduction in soil population byaldicarb and disulfotan treatments. In the nursery application of phorate andfensulfothion at the rate of 0.4 g a.i.fm2 increased shoot height and vigour of theseedlings.


THE PREDATORY BEHAVIOUR OF MONONCHUS AQUATICUS: IrfanAhmad, Section of Nematology, Department of Zoology, Aligarh MuslimUniversity, Aligarh-202001.

The predatory. behaviour of Mononchus aquaticus Coetzee, 1968 wasstudied in agar plotes. Observations were made on the prey catching mechanism,attraction towards prey, predation rate, prey selection and the effect of isolationof predator on predation.

The results indicated that M. aquaticus was not attracted towards preyspecies and contact with prey was necessary to initiate an attack. Once caught,the prey was pulled backwards as a result of a sharp withdrawl of the predator.Small pley were usually swallowed whole but only the internal parts were suckedof the larger ones. The rate of predation varied with the type of prey availableand of the five species used, Cephalobus sp. was preyed on most and Prismatolaimus sp. the least. Aglenchus parvus, Chiloplacus symmetricus and Mesorhabditissp. represented prey of intermediate grouping. Predation of these nematodesseemed to be related to their activity suggesting that the less active species weremore vulnerable to attack than the more active ones. The pattern of predationin a mixed population indicated some degree of selection. Prey numbers and theisolation of predators did not significantly influence the rate of predation.

COMMUNITY ANALYSIS OF SOIL AND PLANT PARASITIC NEMATODES OF HILLY AREAS OF SOUTHERN DISTRICTS OF TAMIL

NADU : G. J. Samathanam andM. L. Chawla, Division of Nematology,Indian Agricultural Research Institute New Delhi-12.

For the past few years Government organizations and other private bodieslike Coffee Board, UPASI, and Cardamom Board are paying much attention inthe hilly areas of South India to bring more area under cultivation of foreign exchange earning potential crops of various beverages, spices and condiments. Inthis target, southern districts of Tamil Nadu share considerable area of about4,72,000 ha. In view of the meagre information available about nematode fauna,a study on the Community analysis of soil and plant parasitic nematodes of hillyareas of southern districts of Tamil Nadu was carried out by analysing 131 soil/rootsamples collected from the rhizosphere of 65 different crop plants, with a view toprovide information about the absolute and relative frequency, density, biomass,prominence and importance values of 43* different nematode species which areidentified under 26 genera, 16 families, 7 super families, 4 sub-orders and 2 ordersof Tylenchida and Dorylaimida. Such a presentation is an improvement over the


conventional way of presenting survey results by mere listing species. This is sobecause the importance value incorporates the energetics of the ecosystem ratherthan the ever-fluctuating rupee value of the crop.

RNA AND RNAse ACTIVITY FROM TOMATO PLANTS IN RELATIONTO RESISTANT RESPONSES AGAINST THE ROOT-KNOT NEMA

TODE, MELOIDOGYNE INCOGNITA : D. Premachandran, Division ofNematology, Indian Agricultural Research Institute New Delhi-l2.

Investigations aimed at exploring the basic molecular mechanism in theplant-nematode interaction in relation to the resistance of tomato plants toMeloidogyne incognita were carried out. The total RNA content increased inroots of both the varieties, the increase being remarkable in the resistant var.SL-120. A general increase in RNA nucleotides was noticed in the inoculatedplants; the increase was in the adenylic and guanylic acids in Pusa Ruby (susceptible var.) while in SL- 120 cytidylic and guanylic acids had increased. In parallel,

the soluble proteins were also observed to increase. A bimodal increase in RNaseactivity in galled tissues, one early and the other quite late during infection wasnoticed. Contrary to this, only a unimodal increase was seen in the resistantreacting variety. The possible contribution of the nematode as contaminants tothe increase in plant RNase was judged to be insignificant. Purification andcharacterization of the RNase activity from the inoculated and healthy plants ofboth the varieties gave clear indications for do novo ~ynthesis of RNase isozymein the inoculated SL-120. The results are hence suggestive of preferential synthesis of RNA in the inoculation tomato, especially in the resistant reacting plants.Indications are there to suggest an acceleration of the protein biosynthetic machinery of the cell quite early during infection. On the basis of the studies conducted

,in this laboratory and elsewhere, a hypothesis on the molecular events takingplace in plant-nematode interaction has been suggested.

POPULATION ESTIMATION OF CITRUS NEMATODE, TYLENCHULUS

SEMIPENETRANS COBB, 1913 : S. B. Sharma and M. L. Chawla, Division

of Nematology, Indian Agricultural Research Institute, New Delhi-12.

For developing diagnostic and advisory services as guides to effective controlof nematode diseasesj accurate estimation of population is the foremost necessity

ABSTRACT ,.OF. PAPERS 133

in the field of applied research in nematology. However, the complete censuson the nematode population in a given area is not possible because of their highnumber as they constitute a major portion of the metazoans inhabiting soil. It istherefore, imperative that sampling and processing techniques, which are basictools for reliable estimation of popultions, be developed and standardized atleastfor nematode problems of economic importance. With this objective and takinginto consideration the almost universal distribution of the citrus nematode,

Tylenchulus semipenetrans and its association with the citrus die-back complex,the present studies were under taken to analyse factors influencing recovery of thenematode from soil as well as roots so that precise informations are obtainedwhich may be ultimately helpful in the understanding of host-parasite relationship. Attempts were made to evaluate i) sampling methods (distance and depthof sampling from tree trunk, root and soil sample size. ii) storage conditions ofthe sample, iii) extraction procedure and iv) effect of temperature on the recoveryof second stage larvae through modified Baermann funnel technique.

Cobbs decanting ,and sieving followed by 0.2% separan treatment or 2%detergent. treatment or 2% ferric chloride treatment or modified Baermann funneltechnique; Seinhorst two flask method and sugar centrifugal floatation methodwere evaluated. Five soil sample size (50, 100, 150,200 and 250 cc); six temperature conditions (15, 20, 25, 27, 30 and 35'C); period of storage of sbil samples(7,17,27, 37, 47, and 57 days) under six temperature conditions (5, 15,20,25,27and 30"C) and one room temperature, three different root weights (3,7 and 'lOg)treated with four different concentrations of hydrogen peroxide and exposed tofour different temperature conditions were evaluated also. All the tested methodswere at par with each other with maximum recovery between temperature rangedf15 ....27°C. The higher temperatures ono' a.nd 35'C Were not conducive for therecovery of nematode population. Sample size, foot weight and storage ofsamples had a marked effecf on the recovery bflarv'ae. 50 cc of soil sample sizewas found to be optimum. Stora.ge of soil.sa11'1plesbelow 20'Cfor seven days didnot change the population but storage at 25'C for seven days resulted in higherrecovery. Size of 3 g of cbopped feeder roots immersed in 30 ml of 5% bydroge'nperoxide and incubated at 20°C for 48 bours was the most effective size for themaximum recovery of nematode larvae. Sampling at 120 cm radial distance fromtree trunk at a depth of 30 cm was an ideal combination for maximum recovery.These studies bave clearly indicated that not only temperature at the extractiontime but also the sample size, the condition of storage of samples, tbe root weightand also the sampling sites are important deteqnining factors in proper eyaluation,of the population dynamics of citrus nematode.


PLANT QUARANTINE IN RELATION TO NEMATODES, IN INDIA:K. C. Sanwal, National Bureau of Plant Genetic Resources, New Delhi-12.

The world wide distribution of several plant parasitic nematodes has nowbeen definitely attributed to the movement of plants and planting material fromone country to another. With the recognition of several plant parasitic nematodesas destructive pests of crops, most countries are now paying greater attention toquarantine inspection of imported material for detection of nematode infestation,than was done in the past. In view of the large quantities and the wide varietyof plants and planting material (seeds, bulbs, corms, suckers, tubers, rhizomes,rooted plants, nursery stock etc.) being imported into India during the past fewyears, it has become necessary to assess the plant quarantine operations in Indiain relation to nematodes.

Problems of undertaking quarantine for nematodes in India are related tothe level of knowledge about nematodes; nature of import policy for plants andplanting material; administrative pattern of Plant Quarantine System; researchon plant quarantine aspects of nematology; availability of post-entry quarantinefacilities, and trained staff; communication between quarantine workers, and alsoio public awareness of the importance of nematodes in plant quarantine.

Basic information on the occurrence, exact distribution, host range andpathogenicity of nematodes existing in India (with the exception of a few specieslike Heterodera avenae, Anguina Iritici) is far from complete. Only when suchinformation on the indigenous nematode fauna is available, can the exclusion of aparticular nematode species be justified on scientific grounds. Quarantine organizations also require compiled and easily retrievable information on plant parasiticnematodes occurring in other countries of the world, for effectively regulating(restricting, prohibiting, imposing special requirements) the importation of plantsand planting material on the basis of pest-risk involved in imports from differentcountries. Considering the variety of planting material entering India, researcheffort on quarantine aspects- of nematology (fumigants, fumigation dosages; hotwater, vapour heat, hot air treatments; nematicidal dips; techniques of detectionand extraction of nematodes; fabrication of special equipment etc.) is practicallynon-existent. Post-entry quarantine facilities at the disposal of Plant Quarantineorganizations, for growing certain types of material in isolation are limited.

To check further spread of nematodes like Radopholus similis, Aphelenchoies besseyi Ditylenchus angustus, Heterodera avenae, Globodera rostochiensis

etc., the simple step of enforcing domestic quarantines may not achieve even alow degree of success until scientifically documented and precise distribution of


these nematodes in the country is worked <Jut, and, until suitable modificationsand/or additions are made in the administrative pattern of the Plant QuarantineOrganization in India. At present, there are no regular State Plant QuarantineOrganizations in India. It is important however, that State Departments ofAgriculture of all States and Union Territories of India should be actively involvednot only in fulfilling the objectives of Plant Quarantine (i.e. preventing the entryof new pests, and preventing further spread of those which are localized) withinthe boundaries of the State, but also in carrying out the centrally sponsoredquarantine projects of national importance. Other modifications pertain to iheexpansion of existing staff and facilities of the Central Plant Quarantine Organization, coupled with a certain degree of decentralization of the organization, perhaps on a regional basis, for facilitating the administration and implementationof Plant Quarantine in a large country like India.

Conducting of short term, in service training courses in nematologicaltechniques and nematodes of quarantine significance etc., for staff working atQuarantine Inspection Stations, enhancing communication between workers ofQuarantine Organations, and a programme of educating the public about dangersof intoducing harmful nematodes through imported planting meterial are alsoconsidered important for effectively carrying out plant quarantine operations inrelation to nematodes.

ABSTRACT OF PAPERS - NEMATOLOGYnematology.in/data/documents/V11N01P95.pdf · 2019-08-20 · with...

Documents

Transcript of ABSTRACT OF PAPERS - NEMATOLOGYnematology.in/data/documents/V11N01P95.pdf · 2019-08-20 · with...