Optimizing Aerosol Dispensers for Mating Disruption of Codling Moth, Cydia pomonella L

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1 J Chem Ecol (216) 42: DOI 1.17/s Optimizing Aerosol Dispensers for Mting Disruption of Codling Moth, Cydi pomonell L Peter S. McGhee 1,2 & Jmes R. Miller 1 & Donld R. Thomson 3 & Lrry J. Gut 1 Received: 2 My 216 /Revised: 2 June 216 /Accepted: 7 June 216 /Pulished online: 1 July 216 # Springer Science+usiness Medi New York 216 Astrct Experiments were conducted in commercil pple orchrds to determine if improved efficiencies in pheromone delivery my e relized y using erosol pheromone dispensers for codling moth(cm), Cydi pomonell L., mting disruption. Specificlly, we tested how reducing: pheromone concentrtion, period of dispenser opertion, nd frequency of pheromone emission from erosol dispensers ffected orienttionl disruption of mle CM to pheromone-ited monitoring trps. Isomte CM MIST formulted with 5 % less codlemone (3.5 mg/ emission) provided orienttion disruption equl to the stndrd commercil formultion (7 mg / emission). Decresed periods of dispenser opertion (3 nd 6 h) nd frequency of pheromone emission (3 nd 6 min) provided level of orienttionl disruption similr to the current stndrd protocol of relesing pheromone over 12 h period on 15 min cycle, respectively. These three modifictions provide mens of sustntilly reducing the mount of pheromone necessry for CM disruption. The svings ccompnying pheromone conservtion could led to incresed doption of CM mting disruption nd, moreover, provide n opportunity for chieving higher levels of disruption y incresing dispenser densities. Keywords Mting disruption. Aerosol dispenser. Pheromone. Codling moth. Pheromone delivery * Peter S. McGhee mcgheeps@gmil.com Deprtment of Entomology, Michign Stte University, Est Lnsing, MI 48824, USA DuPont Crop Protection, 4815 NW runo PL Corvllis, OR 9733, USA Pcific iocontrol Corportion, NE 13th Ct, Vncouver, WA 98685, Cnd Introduction Aerosol pheromone dispensers im to reduce the cost nd lor of ppliction while mintining or improving the effectiveness of moth mting disruption (MD). These devices im to control moth pests primrily in fruit nd nut crops: codling moth (CM), Cydi pomonell L (pple, per, wlnut), Orientl fruit moth, Grpholit molest (usck) (pple), nd nvel orngeworm, Amyelois trnsitell (Wlker) (lmond, pistchio, wlnut). Aerosol dispensers re deployed t densities of h 1, nd ech unit releses c. 7 mg of pheromone every 15 3 min. In Wshington Stte, high levels of CM orienttionl disruption were chieved with Suterr Puffer CM dispensers deployed in grid pttern t 2.5 puffers h 1 ndrelesing7mgcodlemone[(8e,1e)-8,1-dodecdien-1- ol, common nme codlemone, E8,E1 12:OH] every 15 min from 17: to 5: h (Knight 25). These trils suggested tht high-relese, low point-source pheromone-dispenser might e effective for disruption of CM. However, the Puffer CM tretments usully were supplemented with order-ppliction of hnd-pplied pheromone dispensers, such s Isomte CM FLEX (Pcific iocontrol Corp., Vncouver, WA, USA), nd/or supplementl insecticides. Aerosol dispensers (MSU Microspryer, Suterr Puffer CM-O) did not perform s well in Michign field trils when deployed s stnd-lone tctic (Isscs et l. 1999; Stelinski et l. 27). Despite wide-spred nd successful deployment of erosol dispensers, little is known out how the prmeters of opertion (pheromone relese rte, dispenser density, opertion period nd durtion) impct performnce. Understnding these prmeters of opertion could optimize performnce nd improve the cost-effectiveness of erosol dispensers. Experiments exmining the response of mle CM to lureited trps in erosol-dispenser-treted orchrds will help

2 J Chem Ecol (216) 42: optimize these devices. Deploying t density more thn 2.5 h 1 is cost-prohiitive, nd supplementing with highdensity formultions increses the cost of oth lor nd pheromone. Do erosol dispensers need to emit extremely high mounts of codlemone to chieve disruption? The mount of pheromone in erosol formultions ws developed sed upon the mount of pheromone contined in high-density hnd-pplied dispensers deployed t 1 h. Additionlly, erosol dispensers currently operte on fixed progrm ll seson long, dispensing pheromone even when conditions (wind, rin, temperture) re unfvorle for moth flight. New erosol dispenser technology permitting customized progrming my help to conserve pheromone y mtching the period of opertion with tht of the flight window of the trgeted pest or y ltering the quntity of pheromone relesed to elicit n pproprite pest response. McGhee et l. (212) found polyethylene reservoir-dispensers formulted with sustntilly less codlemone (25 75 %) thn Isomte C+ provided similr high-level disruption (95 %) of CM mles. Given these positive results, we postulted tht erosol dispensers relesing pheromone t lower rtes (1 5 % less) could e eqully effective. Improved CM disruption using erosol dispensers my e relized without significntly incresing cost y deploying higher densities of dispensers (5 1 h 1 )thncurrently recommended (2.5 h 1 ) ut relesing lower pheromone concentrtion. This lso would likely help mitigte the prolems encountered on orchrd perimeters when using the low-density erosol pproch. The prmeters (concentrtion, durtion, nd frequency) of pheromone delivery using erosol emitters hve not een investigted since their initil development. A etter understnding of how ltering these 3 fctors impcts moth ehvior could led to incresed doption of this strtegy through improved efficcy without incresing cost. Here, we ddressed three questions importnt to erosol dispenser optimiztion: 1) Do 25 % or 5 % reduced pheromone ctive ingredient (i) relese concentrtions ( g i h 1 / y) disrupt CM s well s current high relese formultions (71 g i h 1 / y); 2) Do reduced periods of pheromone relese (, 3, 6 h) disrupt CM s well s the stndrd 12 h opertion period; nd 3) Do reduced frequencies of pheromone relese (one emission every, 3, 6 min) disrupt CM s well s the stndrd frequency of one relese every 15 min. The success of ny of these options in mintining efficcious CM disruption while sustntilly reducing the pheromone required per h ultimtely provide opportunities for reducing the cost of CM erosol dispenser technologies. Methods All experiments were conducted using Isomte CM MIST (MIST) erosol dispensers (Pcific iocontrol Corp., Vncouver, WA, USA) loded with g of codlemone, E8,E1 12:OH, depending on the experiment. The dispensers re progrmmle, llowing the opertor to chnge the frequency of emission nd period over which pheromone is relesed. Isomte CM MIST dispensers were loded with 17.8, 35.5, or 72 g of codlemone/unit nd relesed 1.8, 3., or 7. mg of pheromone per emission, respectively. Experiment 1 Reduced Pheromone Concentrtion (, 25, 5, nd 1 %) The design of this experiment ws rndomized complete lock (RC). It ws conducted in 212 on two commercil pple frms ner Sprt, MI, USA nd two frms ner Wtervliet, MI, USA. Ech frm consisted of minimum of 4 h of pple. Five 2 h plots of mture pple trees (3-5 m) were rndomly ssigned one of the following tretments on ech frm: Isomte CM MIST 1 % (7 mg emission), 5 % (3.5 mg emission), 25 % (1.8 mg emission), 25 % t 2 rte (5 dispensers h -1), nd negtive control (No MD). Isomte CM MIST units were deployed t 2.5 h 1 for ll ut the 25 % 2 tretment (5 units h 1 ) nd with dispensers uniformly spced c. 63 m prt. Aerosol units were hung in the upper 1/3 of the cnopy (4 m ove the ground), nd positioned to direct pheromone sprys outwrd. Dispensers were progrmmed to deliver 1 emission of pheromone every 15 min from 17 to 5 h from My 23 Septemer 11 (16 wk). Tretments were ssessed y moth cptures in 7 Trécé CM L2 ited Delt-style trps spced uniformly throughout ech plot nd elevted on moo poles to ner the top of trees nd fruit injury evlutions. Trps were monitored weekly, nd sticky trp liners were chnged s necessry to keep the trpping surfce clen. Fruit injury ssessments were conducted prior to hrvest y visully inspecting 12 hlf fruits per tretment. Five releses of sterile codling moths were conducted in ll orchrds. The use of sterile insect relese (SIR) moths provided n evlution y using known nd equl pest density cross tretments. Sterile codling moths were otined from the Okngn-Kooteny SIR progrm in ritish Columi, Cnd. One dy old moths were shipped overnight vi FedEx in Styrofom coolers. Upon receipt, groups of c. 8 SIR CM were dusted with c..1 g of DyGlo pigment powders (green, lue, pink, ornge). Ech DyGlo color group ws ssigned to tretment. Moths were trnsported immeditely in 473 ml Solo continers (DART Inc., Mson, MI, USA) to the field for relese. Approximtely 16 moths (1:1, M:F) were relesed in ech plot per replicte per relese dte; weeks of (June 14 & 27, July 12 & 19, August 14 & 27). Moths were relesed in lte fternoon y gently tossing them into the ir etween two trees t 4 different loctions spced uniformly in the plot. Relesed moths flew directly into the cnopy of the nerest trees. Moth ctch dt were trnsformed to sqrt (x +.5) to normlize the distriutions nd homogenize vrince, nd then were

3 614 J Chem Ecol (216) 42: sujected to generl liner model (GLM) (Systt 13, 29) locked y frms. Differences in pirs of mens were seprted using Tukey s highly significnt differences (HSD) test. Experiment 2 Reduced Period of Opertion (, 3, 6, 12 h) The experimentl design ws RC. It ws conducted in 213 on three frms locted in Sprt MI, USA to test the hypothesis tht reducing the period of pheromone emissions from 12 to 6 or 3 h does not significntly reduce mle CM orienttionl disruption to trps. Isomte CM MIST 5 % i erosol dispensers (35.5 g i/unit) were deployed rther thn the 1 % i (71 g i/unit) due to vilility; dispensers were distriuted uniformly t 2.5 h 1 s the sl tretment. Pheromone dispensers nd trps were hung the sme s in Experiment 1. Four 4 h plots of mture pple trees were ssigned rndomly one of the following dily emission protocols on ech frm: 12 h (48 emissions), 6 h (24 emissions),3h(6emissions),ndnomd treted orchrd s negtive control. Isomte CM MIST units egn operting t 17: h nd cesed opertion fter 12, 6, nd 3 h, respectively, delivering 1 emission of codlemone (3.5 mg) every 15 min over the course of the relese period. This experiment rn from My 2 June 24 (7 wk). Tretment effects were determined y relesing SIR moths into orchrds s descried ove nd mesuring cpture of mle moths in Trece L2 pheromone ited trps. Approximtely 16 moths (1:1, M:F) were relesed in ech plot per replicte per relese dte totling 3 releses; week of (My 29, June 5, 19). Moth ctch dt were nlyzed s in Experiment 1. Experiment 3 Reduced Frequency of Pheromone Relese (, 15, 3, 6 min) The Experiment 2 design, orchrds, nd nlyses were employed to test the hypothesis tht reducing the frequency of pheromone emission elow 1 every 15 min does not diminish orienttionl disruption of CM. The following tretments were rndomly ssigned on ech frm using Isomte CM MIST 5 % i erosol dispensers (35.5 g i) t intervls: 15 min (4 /h), 3 min (2 /h), 6 min (1 /h), or min (No MD) s negtive control. Aerosol dispensers were progrmmed on July 1st immeditely following the completion of Experiment 2; pheromone ws relesed etween 17 nd 5 h. This experiment rn from July 1 August 5 (5 wk). Three seprte releses (July 1, 17, 31) of SIR moths were conducted s in Experiment 2, nd ctch dt ws nlyzed s per Experiment 1. Fruit injury ssessments were not conducted in experiment 2 or 3 due to the nture of the experimentl design; Codling moth injury in experiment 2 tretment plots might directly influence CM injury in experiment 3 tretments, s the sme plots were utilized over time for different tretments. Results Isomte CM MIST reduced moth cptures eqully in plots treted with 25 % (5 units/h 1 ), 5 % nd 1 % (2.5 units/ h 1 ) loding rtes compred to the No MD control (Fig. 1). Mle moth ctch ws suppressed 61, 53, nd 62 %, respectively, in the three tretments. There ws no sttisticl difference in SIR moth cptures in L2 ited trps mong Isomte CM MIST 25 % t the 2 rte (5 units/h 1 ), 5 % (2.5 units/ h 1 ), or 1 % (2.5 units/h 1 ) tretments. Isomte CM MIST t 25 % nd the lower density (2.5 units/h 1 ) hd the highest moth ctch of the pheromone tretments, nd ws not sttisticlly lower thn the control, indicting tht this density nd concentrtion filed to provide orienttionl disruption. Codling moth dmge to fruit ws very low in ll tretments; the highest level detected ws.6 % in the No MD plot. The pheromone treted plots ll hd less thn.5 % injury, nd there were no sttisticl differences etween ny tretments. Few relesed nd wild moths were cught in experiment 2 tht tested the effect of reduced period of opertion. Cptures of SIR moths ws significntly lower in ll pheromone treted locks thn in the untreted control (Fig. 2). Mle moth ctch ws suppressed 56, 47, nd 74 %, respectively, in the 3, 6, nd 12 h tretments. The pttern of cptures ws similr for wild moths. Moth ctch in plots with MIST units operting for 3, 6, nd 12 h did not differ sttisticlly, nd ll pheromone tretments hd significntly lower ctch thn the control (Fig. 3). More moths were cptured during Experiment 3 testing the reduced frequency of pheromone relese thn in Experiment 2. This my e due to wrmer wether during the middle of the summer nd longer flight windows in the evening. Cptures of mrked nd wild moths were sttisticlly lower in ll pheromone-treted plots thn in the control plots (Fig. 3). Moth ctch in plots with MIST units relesing Men SIR CM / Tretment +/- SEM % (2.5) 25% (5) 5% (2.5) 1% (2.5) Codlemone Formultion (%) nd Emitter Density (h -1 ) Fig 1 Cptures of mle codling moth (CM) in pple plots treted with Isomte CM MIST formulted with different concentrtions of codlemone (25, 5, or 1 % t 2.5 units/h 1, nd 25 % t 5 units/ h 1 ), Generl Liner Model Anlyses F =2.74 (4,42), P <.5. Tretments leled with the sme letter re not significntly different (Tukey s HSD test: P <.5)

4 J Chem Ecol (216) 42: Men Mle CM / Tretment +/- SEM A pheromone once, twice, or four times per hour did not differ sttisticlly. Suppression of SIR ctch ws c. 9 % overll for the pheromone tretments compred to the control. Discussion Our results prove tht reducing pheromone concentrtion y 5 % while mintining the numer of point sources per re nd volume of the formultion relesed with ech emission A hours 3 hours 6 hours 12 hours Time Dispensers Operting SIR Wild Fig 2 Cptures of mle codling moth (CM) in Isomte CM MIST treted pple plots dispensing codlemone with incresing durtion (, 3, 6, 12 h), Generl Liner Model Anlyses F =4.5 (3,53), P <.1(wild CM); F = (3,57), P <.1 [SIR (sterile insect relese) CM]. Tretments within popultion (wild, SIR) leled with the sme letter nd cse re not significntly different (Tukey s HSDtest:P <.5) Men Mle CM Tretment +/- SEM A SIR WILD / hour 1 / hour 2 / hour 4 / hour Emissions / hour Fig 3 Cptures of mle codling moth (CM) in Isomte CM MIST treted pple plots dispensing codlemone t different intervls (15, 3, 6 min) etween 17 nd 5 h, Generl Liner Model Anlyses F = (3,54), P <.1 (wild CM); F = 5.38 (3,38), P <.1 [SIR (sterile insect relese) CM]. Tretments within popultion (wild, SIR) leled with the sme letter nd cse re not significntly different (Tukey s HSD test: P <.5) cn provide disruption similr to tht of the full concentrtion. The overll ctch in MIST-treted plots tht exmined reduced pheromone concentrtion ws out hlf of the negtive control. The inhiition of moth ctch in treted plots reltive to the check did not exceed 62 %. Under the circumstnces investigted, none of the concentrtions chieved high level of disruption; >95 % reduction in mle cptures. However, previous studies tht used erosol dispensers tht trget CM resulted in very high levels of disruption (ldessri et l. 213; Knight 25). Smll plot size (2 h) my hve reduced the overll efficcy of disruption. Erly in the development of erosol dispensers, reserchers recognized tht the sptil geometry ssocited with deploying the devices t low densities ment tht lrger plots would e esier to cover with the pheromone plume thn smller plots (ker et l. 1997). The Suterr Checkmte Puffer CM-O lel wrns tht use in orchrds less thn 16 h will led to less thn optiml results, nd it recommends 5 units h 1. Regrdless of plot size, CM ctch ws the sme in 1 % nd 5 % pheromone plots using equl dispenser densities. We postulte CM disruption using 5 % would likely improve with incresing plot size. Reducing pheromone concentrtion 5 % would correspondingly decrese the formultion expense. Pheromone conservtion lso cn e chieved y reducing the period nd frequency of emissions. Altering the period of opertion from 12 to 6 or 3 h gve similr orienttionl disruption. Interestingly, ctch of SIR nd wild mle CM ws inconsistent for the 6 h tretment. Mle SIR cptures under 6 h opertion ws similr to oth pheromone tretments (3 nd 12 h) nd the negtive control, wheres wild moth ctch ws similr only to the pheromone tretments ut not the control. Differences in CM ctch for the 6 h tretment my e skewed y tretment plcement. The 6 h tretment ws directly djcent to the untreted control t 3 out of 4 loctions; immigrting moths my hve elevted ctch in the pheromone plot. Disruption of CM ctch ws high cross ll reduced frequencies of pheromone emissions (15, 3, nd 6 min intervls). Altering the emission frequency from 15 min to 3 or 6 min sves 5 75 % pheromone without loss in efficcy. Dispensing pheromone more frequently is not wrrnted nd does not provide higher level of disruption. Here, we present three djustments to erosol dispensers tht reduce the mount of pheromone necessry for CM disruption in pple. Adopting ny of the three could result in lterntive deployment strtegies, such s incresed dispenser densities, where the svings provided y pheromone conservtion cn offset the dditionl cost of dditionl dispensers. This prctice might negte the recommendtion (Knight 25; Suterr Checkmte CM-O Puffer Lel 211) of pplying dditionl high point-source density dispensers round orchrd perimeters. Future reserch comining ny or ll three of these djustments could result in even greter conservtion of pheromone while mintining high level of CM disruption.

5 616 J Chem Ecol (216) 42: Acknowledgments This project ws funded in prt y Pcific iocontrol Corportion. Specil thnks to Mike Hs nd Jessic Alpers for ssisting in field experiments, Don Armock nd Mthew dgerow for use of their pple orchrds. Complince with Ethicl Stndrds Conflict of Interest The uthors Peter S. McGhee, Jmes R. Miller, nd Lrry J. Gut declre tht they hve no conflict of interest. The Author Donld Thomson works in reserch nd sles t Pcific iologicl Control, ut ws contriuting uthor in the design of experiments including runtime, mount of ctive ingredient, nd numers of dispensing units/c. References ker TC, Ditt T, Mfr-Neto A (1997). Disruption of sex pheromone communiction in the lckheded fireworm in Wisconsin crnerry mrshes y using MSTRS devices. J Agric Entomol 14: ldessri M, Ioritti C, Angeli G (213). Evlution of Puffer CM, relese device of pheromone to control codling moth on pple in Itly. IOC-WPRS ull 91: Isscs R, Ulczynski MJ, Wright, Gut LJ, Miller JR (1999) Performnce of the microspryer with ppliction for pheromone-medited control of insect pests. J Econ Entomol 92: Knight AL (25) Mnging codling moth (Lepidopter: Tortricide) with n internl grid of either erosol puffers or dispenser clusters plus order pplictions of individul dispensers. J Entomol Soc rit Columi 11:69 78 McGhee P, Gut L, Hs M, Miller J, Hung J (212). Field evlution of Isomte Flex CM nd Cidetrk CM meso hnd pplied mting disruption. Proceed 86th Annu Orchrd Pest nd Disese Mngement Conference p. 21 Stelinski LL, Gut LJ, Hs M, McGhee PS, Epstein DL (27) Evlution of erosol devices for simultneous disruption of sex pheromone communiction in Cydi pomonell nd Grpholit molest (Lepidopter: Tortricide). J Pest Sci 8: