Application condition and performance of glyphosate in Turkey

Prof. Dr. M. Nedim DOGAN

Adnan Menderes University, Faculty of Agriculture, Dept. Plant Protection, Weed Science

AYDIN-TURKEY

mndogan@adu.edu.tr

A project supported by Monsanto

GLYPHOSATE IN TURKEY

Perennial crops

About 70 % of fruit growers in Aydin province use glyphosate

Roadsides, Railways, Irrigation channels and other non agricultural areas

In cotton prior to harvest as desiccant

Many different formulations

Satisfactory effect against most weed species

However, it is reported by Monsanto people from Turkey thatherbicide fails in controlling

• Sorghum halepense L. (Pers.) Johnsongrass

• Cyperus rotundus L. Purple nutsedge

• Portulaca oleracea L. Common purslane

• Convolvulus arvensis L. Field bindweed

GLYPHOSATE IN TURKEY

What can be the reason ?

• Some problems concerning application and timing

OR

• Resistance

AIM of the project with Monsanto

• Formulation

• Spray water volume

• Spray water quality

• Weed growth stages

• Climatic conditions during application

Methods

Pot experiments

Pot experiments were carried out in the screenhouseof the weed science laboratory at Adnan MenderesUniversity, Faculty of Agriculture, Turkey. Perennialweeds were grown from rhizomes and P. oleraceafrom seeds. A growing medium of turf: sand: perlit andsoil (1:1:1:1) was used for plant growth.

Rhizomes of S. halepense were planted in 3.8 l pots andrhizomes of C. rotundus, C. arvensis and seeds of P.oleracea were in 3.0 l pots.

Four different glyphosate formulations were used in allexperiments

Formulation Trade name Glyphosate

content

(g a.e./l)

MON 79376 Roundup Star 360

MON 79351 Not commercial yet

in Turkey

480

MON 78273 Cayenne 540

Generic Product Sonround 360

Glyphosate was applied at three doses

2160 g a.i./ha Recommended dose

1620 g a.i./ha 75 % of the recommended (25 % reduced)

1080 g a.i./ha Half dose (50 % reduced)

All herbicide treatments were done by using a spray chamber.First the recommended doses of each formulation wereadjusted. Other doses were then obtained as water dilutions.

MODUL I.Effect of water volume on the efficacy of glyphosate

•Water volume 200 and 600 l/ha

• 600 l/ha water volume was achieved by running 3 times(each with 1/3 spilt dose)

•Experiments were carried out two times.

•Average plant heights at the beginning of the experiments

• Johnsongrass 25 and 22 cm, resp.

•Purple nutsedge 5-6 leaves.

•Common purslane 1-3 branches.

Weed species JohnsongrassCommon

purslane

Purple

nutsedge

Experiment**

NS NSI II

Water volume

(l/ha)200 600 200 600 200 600 200 600

Untreated 100 100 100 100

1080 g a.i./ha (50 %) 8,7 b 37,1 a

NS

1,6 b 18,0 a 34,2 a 41,4 a

1620 g a.i./ha (75 %) 4,5 a 15,7 a 0,3 a 1,9 a 15,6 b 26,0 a

2160 g a.i./ha

(recommended)2,7 a 5,9 a 0,0 a 0,4 a 8,2 b 22,4 a

SEM 4,02 2,91 3,96

Relative fresh weights (%) of tested weed species as affected by water volume

Formulation NS, Results are average of all formulations

Johnsongrass treated withhalf dose of glyphosate in200 l/ha volume

Johnsongrass treated withhalf dose of glyphosate in600 l/ha volume

200 l/ha

600 l/ha

MODUL IIEffect of water quality on the efficacy of glyphosate

Jonhsnograss: 33,6 – 50 cm height

Common purslane: 2-4 branches

Purple nutsedge: 5-6 leaves

Three different spray water having different characteristics

• Clean soft water

•Clean hard water (CaCl2 added)

•River water (from Great Meander River)

10.06.2011

Clean water Clean + CaCl2 River water

Total

Hardness

(German)

1,12

(very soft)

21,84

(hard)

22,40

(hard)

pH 6,31 6,64 7,56

EC (µS/cm) 46 846 1008

K (me/l) 0,10 0,09 0,34

Ca (me/l) 0,10 7,35 2,37

Na (me/l) 0,19 0,23 3,58

Mg (me/l) 0,08 0,17 5,11

Properties of spray water used in Experiments

Relative fresh weight (%) of Sorghum halepense and Cyperusrotundus as affected by spray water quality

Water quality S. halepense* C. rotundus**

Dose (g a.i./ha) 1080 

(50 %)

1080 

(50 %)

1620 

(75 %)

2160 

(100 %)

Untreated control 100

Clean water 4,4 b 21,7 c 18,0 b 6,0 a

Clean water + CaCl2 5,4 b 43,1 b 24,9 ab 11,9 a

River water 63,8 a 73,0 a 30,7 a 13,6 a

SEM 2,33 4,23

Formulation NS, Results are average of all formulations

1. Untreated2. Clean soft water3. Clean hard water4. River water

1 2 3 4 1 2 3 4

1 2 3 4Half dose 1 week after treatment

1 2 3 4

1 2 3 4

1. Untreated2. Clean soft water3. Clean hard water4. River water

Recommended dose 1 week after treatment

Effect of weed growth stage on the efficacy of glyphosate

•Water volume: 200 l/ha•Growing weeds within different intervals•Treatment at the same time

Growth stagesEarly Middle Late

Johnsograss: 22 cm 40 cm 80 cm

Common purslane: 3-4 branches 5-6 branches flowered

Purple nutsedge: 3-4 leaves 6-8 leaves 13-14 leaves

Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)

Growth stage Early Middle Late Early Middle Late

Untreated 100 100

Glyphosate 0,8 b 3,9 b 19,7 a 0,8 b 3,0 b 17,4 a

SE 2,8

Relative fresh weight (%) of Sorghum halepense as affected by growth stage

Effect of weed growth stage on the efficacy ofglyphosate on Sorghum halepense

Early22 cm

Middle40 cm

Late80 cm

1 2 3 41 2 3 4

1 2 3 4

1. Untreated2. 1080 g3. 1620 g4. 2160 g

Half dose 2 weeksafter treatment

1 2 3 4

Effect of weed growth stage on the efficacy ofglyphosate on Cyperus rotundus

Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)

Growth stage Early Middle Late Early Middle Late

Untreated 100 100

Glyphosate 100 a 43 b 88,9 a 53,6 a 3,7 b 36,8 a

SE 9,8

Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)

Growth stage Early Middle Late Early Middle Late

Untreated 100 100

Glyphosate 29,5 b 16,9 b 100,0 a 6,8 b 12,1 b 48,4 a

SE 7,1

Early 3-4 leaf Middle 6-8 leaf

Late 10-13 leaf

1 2 3 4 1 2 3 4

1 2 3 4

1. Untreated2. 1080 g3. 1620 g4. 2160 g

Recommendeddose 3 weeksafter treatment

Effect of weed growth stage on the efficacy ofglyphosate on Portulaca oleracea

Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)

Growth stage Early Middle Late Early Middle Late

Untreated 100 100

Glyphosate 2,7 c 25,0 b 52,9 a 1,4 c 23,1 b 49,8 a

SE 4,0

Dose (g a.i./ha) 1620 (75 %) 2160 (100 %)

Growth stage Early Middle Late Early Middle Late

Untreated 100 100

Glyphosate 5,3 c 100,0 a 86,3 b 3,5 c 86,3 a 60,4 b

SE 9,0

Early3-4 branches

Middle5-6 branches

Late Beginning of flowering

1 2 3 4 1 2 3 4

1 2 3 4

1. Untreated2. 1080 g3. 1620 g4. 2160 g

Half dose 2 weeksafter treatment

RESULT

All investigated factors influenced theperformance of glyphosate on all weed species

Early growth stages, low water volume andclean spray water affected the glyphosateperformance positively

Herbicide formulation was not important

Recommended dose provided in most casesreliable weed control

Problem weeds reported by Monsanto people in Turkey

Johnsongrass:

Quite sensitive to glyphosate even at the larger growth stages.

Problems can be attributed to misapplications, low doses incombination with wrong water volumes and low water quality

Common purslane:

Quite sensitive to glyphosate only at early growth stages, butthe sensitivity is lower as plants become older. Water volumeand quality affected the glyphosate performance on this weedslightly

Problems can be associated with wrong application timings(larger growth stages and/or low application doses

Purple nutsedge:• Less sensitive than other two species, only recommendeddose with low water volume, good water quality andsuitable growth stages provide satisfactory weed control

•Problems can be associated with all investgated factors,but still more investgations are needed to improve theefficacy

Field bindweed: ???

Further Studies (Pot Experiments)

Effect of climatic factors during application time (time of day) onglyphosate efficacy

In these experiments, interactions between the climatic conditionsduring the application and glyphosate efficacy will be evaluated.

Herbicide treatments will be done in the morning early, duringmidday and at the evening.

Temperature, humidity and light conditions will be recorded

Interactions among water volume, water quality, growth stagesand application time (time of day)

Further Studies (Field Experiments)

• Since results showed that purple nutsedge (C. rotundus) wasreal problem, this weed will be aimed in field experiments

• Since it was not possible to work with field bind weed (C.arvensis) in pot experiments, a field experiment will be alsoconducted for this weed

• 2 glyphosate formulations X 2 water quality X 2 growth stagesX 2 application times (time of day) X 3 replications

• An experiment with C. arvensis has started on 11‐12th June2011 in a fig orchard in Aydin ‐ Turkey

During field experiment, 10.06.2011

Significant thanks to Monsantofor financial support

Thank you very much for yourattention