NEW YORK FRUIT QUARTERLY • VOLUME 15 NUMBER 4 • 2007 23

In 2002, severe outbreaks of two species of internal-feeding Lepidoptera(worms) began occurring in apple pro-

duction regions of Western NY. Theseoutbreaks caused severe financial lossesto growers throughout this region be-cause numerous loads of apples were re-jected for fresh or processing markets.Initial studies conducted in field efficacytrials showed that neither the organo-phosphate (OP)-based technology com-monly used at the time nor programs re-lying on more selective reduced-riskproducts could reliably provide adequate,cost-effective control of these pests inhigh-risk commercial orchards withinthese outbreak areas.

The two primary species responsiblefor this problem were oriental fruit moth(OFM), Grapholita molesta, and lesserappleworm (LAW), G. prunivora. Al-though they have been present for years,these pests have only recently become asource of concern to NY growers. Becauseof insecticide resistance, regulation-driven changes in pesticide programs,and possibly ecological factors, growershave had to start making special efforts –often for the first time in their experience– to control them. The initial reaction ofmany growers who discovered internalworms in their fruit was to respond withmultiple preventive applications of harshbroad-spectrum or specialty pesticides;eventually, some added mating disrup-tion in combination with the sprays. Thefact that these decisions were often madewithout any formalized evaluation of the

In recent years severeoutbreaks of internal-

feeding worms (primarilyoriental fruit moth andlesser appleworm) hascaused severe financial

losses to growers through-out Western NY State.

Numerous loads of appleswere rejected for fresh or

processing markets.We have studied the use

of various pheromones formating disruption in

conjunction with properlytimed pesticides to reduce

the economic lossescaused by these worms.

Comparisons of PheromoneDispenser Technologies forMating Disruption ofInternal-Feeding Lepidopterain Apples, 2004-2006Arthur Agnello and Harvey ReissigDepartment of Entomology, NYSAES, Cornell University, Geneva, NY

need or effectiveness of the specific tac-tics employed, makes it difficult to assesswhether these programs were worthwhileor justified.

Orchards affected by these pests canrequire up to four extra sprays of conven-tional pesticides during the summer.These late-season sprays are problematicbecause of secondary pest outbreaks andgreater concerns over farm worker risk.Our goal was to mitigate this potentialrisk by preventing the problem before itcould occur, through the use of least-toxicalternatives such as mating disruptionand biopesticidal materials, with a selec-tive reduced-risk toxicant being called foronly in the event that these tactics werenot effective. During the past five years,pheromones for mating disruption wentfrom being a tactic that was seldom con-sidered to one that has generated substan-tial interest, but recommendations ontheir use has been hampered by the lackof experience with this approach in NY

and the evolving product choices in themarket. From 2004 to 2006 we conducteda number of assessments of three differ-ent pheromone-dispensing technologiesavailable to determine their potential use-fulness in controlling internal-feeding

Figure 1. Isomate twist tie Figure 2. Isomate Twin-tube tie.

This work was supported in part by the New York Apple Research andDevelopment Program.

24 NEW YORK STATE HORTICULTURAL SOCIETY

worms in NY apple orchards. Our ap-proach was to run side-by-side compari-son plots of the different pheromoneproducts on commercial farms judged tobe at various levels of risk for this type ofpest attack.

Procedures

Specifics of the test sites each year areas follows:2004 This trial was conducted in mixed

plantings of fresh and processingapples on six commercial farms inWayne and Ontario Counties. Plotsize varied from 3.0–5.0 acres. Applevarieties included Gala, R.I. Green-ing, Golden Delicious, Red Deli-cious, Monroe, Ida Red, Empire, andMcIntosh.

2005 Tests were conducted in mixedplantings of fresh and processingapples on five commercial farms inWayne, Orleans and Niagara Coun-ties. Plot size ranged from 4.0–5.0acres. Apple varieties included Gala,Rome, Golden Delicious, Red Deli-cious, Ida Red, Mutsu, Ben Davis,20-Ounce and McIntosh.

2006 Plots were set up in mixed plantingsof fresh and processing apples onnine commercial farms in Wayne,Orleans and Niagara Counties. Plotsize was between 2.2–8.2 acres.Apple varieties included Cortland,Empire, Fuji, Gala, Golden Deli-cious, Honeycrisp, Ida Red, McIn-tosh, Monroe, Mutsu, Red Delicious,Rome, and 20-Ounce.

The pheromones were deployed overthe top of the growers’ normal insecticideprogram, thus serving as a supplementto the chemical control method. Thepheromone treatments used were: 1)

Figure 3. MSTRS pheromone packet Figure 4. Deployment of MSTRS dispenser using a pole applicator

Isomate polyethylene ties; 2) MSTRSOFM high-yield, low-density pheromonepackets; 3) Hercon Disrupt Micro-Flake,a sprayable plastic laminate, all appliedagainst the 2nd and subsequent genera-tions of OFM, LAW, and codling moth(CM). Codling moth was a target speciesonly in some sites during 2006, so specificIsomate and Hercon products were usedas appropriate to each farm’s pest pres-sure; the MSTRS product was availableonly for OFM. Because of the limitedamount of information on CM matingdisruption generated by these trials, effi-cacy against codling moth is not ad-dressed in this report. The OFM productswere directed additionally against LAW,as these two species have similar phero-mone blends (OFM, 98:2% of Z:E8-12:OAc; LAW, 92:8% Z:E8-12:OAc). In allcases, growers managed the first genera-tion broods of these pests with their con-ventional pesticide applications that weredirected primarily against plum curculioand obliquebanded leafroller occurring atand immediately following petal fall.

The Isomate (CBC America Corp.,Commack, NY) products were appliedprimarily between 14–22 June over thethree years (except for the Isomate-MRosso, as noted below), and included thefollowing:• Isomate-M 100, a polyethylene tie

(Figure 1) containing 232.1 mg ofOFM pheromone blend (88.5 : 5.7 :1.0% of Z:E8-12:OAc : Z8-12:OH),deployed at a rate of 100 ties per acre.

• Isomate-CM/OFM TT, a “twin tube”assembly of two ties (Figure 2) con-taining 423.6 mg of a multi-speciesblend for all three species: 58.4%E8,E10-12:OH; 9.23% 12:OH; 1.87%14:OH; 21.25% Z8-12:OAc; 1.36% E8-

12:OAc; and 0.23% Z8-12:OH, de-ployed at a rate of 200 ties per acre.

• Isomate-M Rosso, an extended-life tiecontaining 250.2 mg of OFM phero-mone blend, as above, applied be-tween 16–22 April at a rate of 200/ties acre at four of the six sites usedin 2004.A pheromone packet (Figure 3), us-

ing “MSTRS” technology (MeteredSemiochemical Timed Release System,AgBio Inc., Westminster, CO) consisted offood-grade plastic enclosing a 6.4 x 6.4 cmnatural fiber pad containing 2.63 g ofOFM pheromone (85.4 : 5.5 : 0.9% of Z:E8-12:OAc : Z8-12:OH), which was deployedin a grid pattern at a density that variedfrom 5–8 per acre in 2004 and 2005, to 10per acre in 2006. A pole+hoop applicatorwas used to position the dispensers, hungby a rubber band or wire loop, in the topone-third of the tree canopy (Figure 4).Deployment of these dispensers tookplace from 9–13 July in 2004, and 17–23June in 2005 and 2006.

The Disrupt Micro-Flake (HerconEnvironmental, Emigsville, PA) productswere 3 x 3 mm solid matrix laminate chips

Figure 5. Hercon Micro-Flakes

NEW YORK FRUIT QUARTERLY • VOLUME 15 NUMBER 4 • 2007 25

Figure 7. Hercon Micro-Flakes stuck to apple foliageFigure 6. Application of Hercon Micro-Flakes using an ATV-mountedmodified leaf-blower.

(Figure 5) impregnated with OFM phero-mone (7.83 : 0.51 : 0.08% Z:E8-12:OAc :Z8-12:OH), applied at a rate of 19.2 g a.i.per acre, or 8 oz of flakes per acre. Appli-cations were made using a modified leafblower (Arena Turbo-Tac) mounted on anATV traveling at 6–7 mph down the rows(Figure 6). The flakes were stuck to thetree foliage (Figure 7) using an acrylicsticker (Micro-Tac) applied as they wereblown from the machine. The HerconFlake treatments were applied at foursites between 7–8 July in 2005, and at three

Figure 9. Total lesser appleworm moths per trap caught during Julyand August in all pheromone treatment plots compared with numberscaught in the respective nondisrupted comparison plots, 2005–2006.

Figure 8. Total oriental fruit moths per trap caught during July andAugust in all pheromone treatment plots compared with numberscaught in the respective nondisrupted comparison plots, 2004–2006.

OFM Pheromone vs. Non-MD Plots

Mean total moths per trap (nondisrupted)

Mea

n to

tal m

oths

per

trap

(MD

)

0

0

2

4

6

8

10

12

10

IsomateMSTRSHercon

100 1000

LAW Catches in Pheromone vs. Non-MD Plots

Mea

n to

tal m

oths

per

trap

(MD

)

0

2

2

3

4

5

IsomateMSTRSHercon

Mean total moths per trap (nondisrupted)

0 10 155 20 25 30

sites between 29 June–14 July in 2006.Attempts to apply this treatment at threeadditional sites in 2006 were preventedby equipment malfunction caused byjams in the hopper feeder mechanism andsticker blockages in the flake auger.

Pheromone treatment efficacy in de-pressing adult male trap catch was moni-tored with pheromone traps in each dis-rupted plot as well as in a nondisruptedcomparison planting on the same farm orin the same general area. Pheromonetraps were checked weekly starting before

deployment of the mating disruptiontreatments until shortly before harvest.Although OFM adult catches were moni-tored all three years, LAW trap data wastaken only in 2005 and 2006. Becausepheromone mating disruption was notanticipated to be effective enough toeliminate the need for all additional in-secticide sprays, a fruit sampling proce-dure was used to assess the need and tim-ing for specific pesticide sprays directedagainst the 2nd and subsequent genera-tions of these species. The fruit sampling

protocol consisted of weekly on-tree fruitinspections conducted from mid-Julythrough August, comprising 300 fruits perplot during the first week and 100 fruitsper plot on subsequent weeks, to detectthe initial occurrence of any OFM or LAWlarval fruit damage in time to curtail fur-ther infestation. Whenever an inspectionsession resulted in detection of at least onedamaged fruit, the grower or consultantwas notified so that they could determinewhether a special spray of a selective pes-ticide was needed for adequate control ofinternal Lepidoptera. An evaluation wasmade of larval fruit-feeding damage atharvest by examining fruit samples fromeach pheromone plot for internal and sur-face injury. When possible, comparisonswere made with fruit from nondisruptedplantings in most, but not all cases, forthe 2005 and 2006 trials.

Results

Pheromone Deployment. As ease ofuse and labor requirements are consid-erations in deciding the type of phero-mone dispenser to be used in a particu-lar situation, data were taken on the timeand number of people required to deploythe pheromone dispensers in each plot.In 2004, the MSTRS product required be-tween 7.1–12.0 min for one individual toapply one acre. Time measurements forhand-applied deployment of the twist-tieOFM dispensers averaged approximately240 ties/hr/person, or 25 min per acrefor the Isomate M-100, and 50 min peracre for Isomate Rosso. The MSTRS timerequirements correspond to a ~50–70%reduction over the M-100 ties, and ~75–85% over the Rosso ties. Records werealso kept in 2006 of the amount of timerequired for application of each type ofpheromone dispenser, and althoughthere was some variability due to differ-ences in the orchards’ physical character-istics and treatment combinations, thefollowing average times were deter-mined: Isomate-M, 37 min/acre/person;Isomate CM/OFM, 34 min/acre/person;MSTRS, 14 min/acre/person; Hercon, 5min/acre (one person driving, but a sec-ond was needed to assist, and setup timerequired was considerable).

Trap Catches. 2004. Pheromone trapcatches of OFM adult males in the testsites were lower than they might nor-mally have been, owing to unfavorablecool and rainy weather during July andAugust. Nevertheless, sufficient numbersof moths were caught in the non-dis-rupted comparison plots to indicate the

degree of effectiveness of the pheromonetreatments in the adjacent plantings. Boththe Isomate M-100 and Rosso treatmentscompletely suppressed OFM trap catchesin their respective plots for the durationof the study; in four of the six sites, trapsin the MSTRS plots caught 1-2 moths onone or two occasions.

2005. Trap catches of OFM and LAWwere generally suppressed to low levelsin all pheromone treatment plots duringthe mid- and late summer, although somebreakthrough captures did occur. Thustrap shutdown was not absolute in allcases. Two plots with notable OFMcatches were the MSTRS and Hercontreatments at the Newfane site. Theseplots were located near a non-disruptedorganic apple planting with a high OFMpopulation, so it is possible that immi-gration from that block was too severe tobe completely disrupted by the phero-mone treatments in our plots.

2006. Oriental fruit moth pressurewas considerable at the Williamson,Newfield, and Kendall sites, but all treat-ments showed low trap numbersthroughout the season; likewise, lesserappleworm was very numerous atRidgeway, Gaines, Williamson, Newfield,and Kendall, but the respective OFMpheromone treatments effectively de-pressed these trap numbers as well.

As a means of assessing the relativeability of the three pheromone treatmentsto disrupt the chemical communicationbetween male and female moths over thecourse of all the trials conducted at these20 sites over a three-year period, the to-tal number of moths per trap caught ineach of the pheromone plots during thedisruption period (2nd and subsequentgenerations) was compared against thenumber caught over the same period ina nondisrupted planting nearby. This wasdone for both oriental fruit moth (Figure8) and lesser appleworm (Figure 9). Whileall of the pheromone products exhibitedsubstantial activity in depressing trapcatches, a plot of the comparisonsshowed that the Isomate ties, in general,tended to be the most effective of thethree dispeners, and the Hercon flakeswere less effective, particularly as popu-lation pressure increased. It must be ac-knowledged that both the MSTRS andHercon products were still in the devel-opmental process, and their performancewas likely impacted by some factors yetto be both addressed and improved uponby the manufacturers.

Fruit Damage. In no case did thegrower rely exclusively on mating disrup-

tion to prevent fruit damage by internal-feeding larvae, so it is not possible to as-sess the treatments’ efficacy as a sole tac-tic in managing these pests. Nevertheless,these trials did afford an opportunity toevaluate each pheromone treatment’srelative management value when used incombination with the grower’s normal in-secticide program, and in many cases ascompared with that program without theuse of pheromones (Table 1).

Our notifications to the growers offinding fruit damage during the in-sea-son fruit inspections did not always re-sult in a decision to apply an extra sprayfor internal worm control. In 2005, the twosuch occasions at the Yates site happenedto correspond with the grower’s sched-uled applications of materials againstother pests that also had some activityagainst OFM. The Alton orchard, whichwas an organic block with a history ofsevere internal worm pressure, was on apreventive schedule of presumably themost effective organically acceptable ma-terials available against internal worms(B.t., codling moth virus, and kaolin clay),so the grower was not relying on our re-ports for his spray decisions. At theNewfane site, a spray was applied for in-ternal worms in all the pheromone plotsbecause of the grower’s concern about theorchard’s proximity to nondisruptedmoth populations, even though damagehad been found in only one treatmentduring one inspection. In 2006, incidenceof in-season fruit injury was extremelylow except at Newfield, Williamson, andGaines, each of which required two noti-fications of damage to the grower or theirconsultant. In contrast to the previousyear, these farms, as well as Ridgeway(one notification), did receive 1-2 directedapplications of a selective insecticideagainst encroaching larval populations asa result.

Fruit damage caused by internal-feeding Lepidoptera at harvest was verylow in all the 2005 treatments at three ofthe five pheromone-disruption sites(Table 1). At the Newfane site, the Isomateplot sustained approximately 10% fruitdamage, although its proximity to anondisrupted organic planting with ahigh population could have been a con-tributing factor. Additionally, an unantici-pated large codling moth population oc-curred that was not being disrupted, sodamage from this species was likely in-cluded in the harvest evaluation, as noeffort was made to distinguish betweenOFM and CM damage. The Alton organicsite had previously suffered relatively

NEW YORK FRUIT QUARTERLY • VOLUME 15 NUMBER 4 • 2007 27

TABLE 1

Percent deep (internal) and sting (surface) fruit injury1 at harvest in pheromone-treated and nondisrupted grower standard plots, 2005-2006.

Site Treatment Sting Deep Total Site Treatment Sting Deep Total

2005 2006

Newfane Isomate 0.3 b 9.3 b 9.6 b Ridgeway Isomate 0 a 0.1 a 0.1 aMSTRS 0.1 ab 2.0 a 2.1 a MSTRS 0.1 a 0.4 a 0.5 abHercon 0 a 1.0 a 1.0 a Hercon 0.1 a 0.3 a 0.4 ab

Grower Std 0.1 a 0.6 a 0.7 bYates Isomate 0.1 a 0.1 a 0.2 b

MSTRS 0.2 a 1.6 b 1.8 ab Williamson Isomate 0.1 a 2.8 a 2.9 aHercon 0.1 a 0.6 a 0.7 b MSTRS 0 a 1.8 a 1.8 abGrower Std 0.2 a 1.6 b 1.8 a Grower Std 0 a 0.1b 0.1 c

Lake Isomate 0 a 0 a 0 a Lake Isomate 0 a 0 a 0 aMSTRS 0 a 0 a 0 a MSTRS 0 a 0 a 0 aHercon 0 a 0 a 0 a Grower Std 0 a 0 a 0 aGrower Std 0 a 0 a 0 a

Gaines Isomate 0.1 a 0.3 a 0.4 aRidge Isomate 0 a 0.1 a 0.1 a Grower Std 0.3 a 0.4 a 0.7 a

MSTRS 0.1 a 0.1 a 0.2 aHercon 0 a 0 a 0 a Sodus Isomate 0 a 0.2 a 0.2 a

MSTRS 0 a 0.1 a 0.1 aAlton Isomate 0.6 a 7.2 a 7.8 a Hercon 0 a 0.1 a 0.1 a

MSTRS-1 2.1 a 15.6 b 17.7 b Grower Std 0 a 0 a 0 aMSTRS-2 0.9 a 6.0 a 6.9 a

Newfield Isomate 0.1 a 0.3 a 0.4 aHercon 0.1 a 2.7b 2.8 bGrower Std 0.2 a 4.0b 4.2 b

Olcott Isomate 0 a 0 a 0 aMSTRS 0 a 0.0 a 0 aGrower Std 0 a 0.2 a 0.2 a

Wolcott Isomate 0 a 0 a 0 aMSTRS 0 a 0 a 0 aGrower Std 0.1 a 0 a 0.1 a

Kendall Isomate 0 a 0 a 0 aMSTRS 0 a 0.1 a 0.1 aGrower Std 0 a 0 a 0 a

1Within a site, values in the same column followed by the same letter are not significantly different at P=0.05 level (Fisher’s protected lsd test).

high fruit damage the previous season.Damage in all the treatments here rangedfrom 7–17% damage, which the growerindicated was relatively acceptable for theorganic processing market, and a measur-able improvement over the previous sea-son.

In 2006, fruit damage at harvest wasvery low in all treatments, and at six ofthe nine sites there was no statistical dif-ference between the pheromone plots andthe respective Grower Standards (Table1). Only two of the nine sites, Ridgewayand Newfield, had significantly less fruitdamage in one of the pheromone plots—Isomate, in both cases—than in the non-disrupted Grower Standard, and at onesite, Williamson, fruit damage was actu-ally higher in the pheromone treatmentsthan in the Standard. In this case, prox-imity to a large bin storage area (that mayhave been a source of uncontrolled moths)was undoubtedly a contributing factor.This was likely a situation where the use

of farm-wide mating disruption wouldhave been a potential solution.

Assessment

Although the pheromone treatmentstested were generally a useful componentof the OFM and LAW management pro-grams in these orchards, some factors canbe identified that potentially contributedto less-than-optimal management: plotsize was not large enough to overcomethe possibility of immigration by matedfemales; moth population pressure wassometimes too high to be effectively dis-rupted by the pheromone treatments; thepheromones were mostly applied againstonly the 2nd and subsequent generations,leaving the potential for damage from the1st generation. The in-season fruit inspec-tion regimen appears to be effective andreliable, but it is difficult to convincegrowers to wait for evidence of even a lowlevel of damage in their orchards before

applying a special spray against thesepests. Pesticide use against these speciescould be reduced in situations of low tomoderate population pressure, wheremating disruption could be relied uponto adequately mitigate potential fruit in-festations.

In general, considering the overalllevels of pest pressure occurring in someof these orchards, and the economics (con-sidering both materials and labor) ofimplementing these pheromone treat-ments, it is possible that internal wormproblems in many NY orchards could beadequately addressed by adjusting pesti-cide spray schedules, improving spraycoverage, or by using selective productsfor a limited number of designatedsprays. In 2006 and 2007, we have seenevidence of the increasing importance ofcodling moth as a contributor to internalfruit-feeding damage in a number ofWestern NY orchards. This certainly com-plicates the management requirements

for this pest group, and any decision to use mat-ing disruption as a supplemental tactic will needto take this additional species into account. Al-though these tactics represent a substantial in-creased cost in a crop protectant program, theymay be necessary for avoiding the higher priceof having even a single load rejected by the fruitbuyer. Ongoing work in this area will be directedat optimizing more farm-wide managementstrategies, in order to improve the effectivenessof both mating disruption and selective insecti-cide use and to diminish the potential for immi-grating moths to overcome more localized con-trol programs.

Acknowledgments

Thanks are due to D. Bartleson, B. Beckens,J. Bittner, D. Datthyn, R. DeBadts, R. Endres, C.Hance, D. Hartley, R. Farrow, T. Furber, O. Kalir,T. Kappus, S. Knapp, D. Oakes, G. Pepe, K. Tram-mel, and M. Zingler, for allowing these trials tobe conducted on their farms; to M. Burlee, J. Eve,J. Misiti, and R. Paddock for coordinating thesetup and maintenance of the plots and commu-nications with the growers; to D. Combs, R.Falkey, N. Gottschall, D.A. and D.M. Mitchell,R. Mussack, M. Tapscott, and J. Watt for fieldassistance in plot establishment and data collec-tion, and to T. Baker, J. Meneley (AgBio, Inc.), P.Owens (Hercon Environmental), and G. Stamm(CBC America) for their cooperation in provid-ing and helping to apply the pheromone prod-ucts. This work was partially funded by grantsfrom the NY Apple Research and DevelopmentProgram, Motts (Cadbury Schweppes), the NYSIPM Program, the IR-4 Biopesticides Program,and Hatch Federal Formula Funds.

Art Agnello is a research and extension professor inthe Department of Entomology who leads Cornell’sextension program in fruit entomology. HarveyReissig is a research professor in the Department ofEntomology and leads Cornell’s Pest ManagementEducation Program.