Small Cages with Insect Couples Provide a Simple Method for a Preliminary Assessment of Mating Disruption

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1 1 Pulished in ScientificWorld Journl, 12, Vol. 12, Article ID 9468, 1-8 which should e used for ny reference to this work Smll Cges with Insect Couples Provide Simple Method for Preliminry Assessment of Mting Disruption FrnçoiseBrind, 1, 2 Ptrick M. Guerin, 2 Pierre-Joseph Chrmillot, 1 nd Ptrik Kehrli 1 1 Sttion de recherche Agroscope Chngins, Wädenswil ACW, CP 112, 12 Nyon, Switzerlnd 2 Institute of Biology, University of Neuchâtel, Rue Emile-Argnd 11, 9 Neuchâtel, Switzerlnd Correspondence should e ddressed to Ptrik Kehrli, ptrik.kehrli@cw.dmin.ch Mting disruption y sex pheromones is sustinle, effective nd widely used pest mngement scheme. A drwck of this technique is its chllenging ssessment of effectiveness in the field (e.g., sptil scle, pest density). The im of this work ws to fcilitte the evlution of field-deployed pheromone dispensers. We tested the suitility of smll insect field cges for preevlution of the impct of sex pheromones on mting using the grpe moths Eupoecili miguell nd Loesi otrn, two mjor pests in vineyrds. Cges consisted of cuic metl frme of 35 cm sides, which ws covered with mosquito net of 15 µm mesh size. Cges were instlled in the centre of pheromone-treted nd untreted vineyrds. In severl trils, 1 to couples of grpe moths per cge were relesed for one to three nights. The proportion of mted femles ws etween 15 to 7% lower in pheromone-treted compred to untreted vineyrds. Overll, the exposure of eight couples for one night ws dequte for compring different control schemes. Smll cges my therefore provide fst nd chep method to compre the effectiveness of pheromone dispensers under stndrdised semi-field conditions nd my help predict the vlue of setting-up lrge-scle field trils. 1. Introduction The use of synthetic insecticides since the end of the Second World Wr hs served to increse considerly the world s food production, ut these pesticides lso compromise the environment nd humn helth [1 3]. Moreover, their extensive use fvours the development of resistnt insect pests nd hrms eneficil insects, occsionlly resulting in the outrek of secondry pest species [4]. Socil wreness of the drwcks of these clssicl insecticides in the erly sixties urged the iotechnologicl industry to develop sfer nd more ecologiclly friendly lterntives [5, 6]. One of these lterntives ws the interfering with pheromonemedited mte-finding systems [7, 8]. Gston et l. [9] were one of the first to confirm tht premting communiction etween sexes could e disrupted y relesing synthetic sex pheromones into the tmosphere. The diffusion of pest s pheromone impirs the ility of mles to locte sexully receptive femles nd so reduce or even prevent mting [1, 11]. Tody, the vlidity of mnipulting nd interfering with insect olfctory communiction systems vi the use of synthetic pheromones hs een demonstrted for mny insect species, nd mting disruption hs een estlished s n effective nd sustinle integrted pest mngement mesure in rod rnge of cropping systems [7, 12]. For exmple, mting disruption hs een implemented to control the codling moth Cydi pomonell in pple nd per orchrds, the pink ollworm Pectinophor gossypiell in cotton nd the grpe moths Eupoecili miguell nd Loesi otrn in vineyrds [7]. Overll, mting disruption is the result of ehviour nd physiologicl effects, which cn e clssified s completive ttrction, cmouflge, nd desensitistion [8, 13, 14]. A downside of mting disruption is the lorious development process of pheromone dispensers s well s the chllenging ssessment of its effectiveness [15]. Electrophysiologicl responses of ntennl receptor neurons re useful first step to identify the sic chemicl components of sex

2 2 pheromones. After identifiction, the components need to e synthesised in the lortory nd their ttrctiveness hs to e tested in ited trps deployed in the field. The following step is to evlute the effectiveness of the developed pheromone dispensers for mting disruption in the ctul crop. This is usully done y ssessing pest densities or crop dmge in commercil fields treted with pheromone dispensers compred to comprle fields tht remined untreted. To chieve relile results, pheromone-treted fields should e of miniml size, quite frequently up to three hectres [16, 17]. Becuse pheromone dispensers re idelly evluted on sizele scle, the environmentl conditions previling in different fields used for tests re rrely like. The undnce of pests, crop vrieties, culturl prctices, microclimte, nd soil cn vry significntly etween treted nd untreted plots. Otining sttisticlly sound dt requires therefore mny independent repetitions, which is demnding in terms of time, spce, nd costs. Severl lterntive methods hve een proposed for preliminry ssessment of pheromone dispensers for mting disruption. One of these is the exposure of tethered virgin femles in pheromone-treted nd untreted fields. After defined period, exposed femles re collected nd dissected in order to determine the presence of spermtophores or sperms [18]. However, femles re exposed in quite rtificil mnner, where nturl courtship ehviour is frequently compromised. In ddition, these defenceless tethered femles re regulrly consumed y predtors [19]. With the im of testing the effectiveness of pheromone dispensers in more nturl setup, Doye nd Koch [15] proposed the use of lrge insect enclosure field cges (e.g., m). These cges were set up in pheromone-treted nd untreted fields, nd defined numer of mles ws relesed within ech cge. To ssess the effectiveness of pheromone dispensers, femles were exposed in smll netted oxes in stndrd delt-trps nd the numer of mles recptured in the two tretments compred. A similr pproch ws lso tken y severl other uthors [ 25]. These uthors exposed defined numer of insect couples in field cges, ut their cges were significntly smller (e.g., etween.1 nd.2 m 3 ) nd the effectiveness of mting disruption ws evluted y dissecting exposed femles to ssess their mting sttus. Even though such smll insect field cges were used in the pst to ssess mting disruption [ 25] or t lest the noncompletive mechnisms mediting disruption [13], they re not commonly employed for testing newly developed pheromone dispensers. A refinement of these smll cges my therefore provide welcome sset to the iotechnologicl industry in order to otin preliminry nd reltively rpid indictions of pheromone dispenser s effectiveness in the field under stndrdised conditions. With this in mind, we mde use of the Europen vine moth, Loesi otrn (Den. & Schiff.), nd the grpe erry moth, Eupoecili miguell (Hüner). These two tortricid moths coexist over lrge prt of Europe where they represent the two mjor lepidoptern pest insects of grpevines (Vitis vinifer L.). Wheres dults of L. otrn re crepusculr, E. miguell is nocturnl [26]. Lrve primrily feed on shoots, flowers s well s fruits, nd wounded erries re more vulnerle to the growth of pthogenic fungi such s otrytis (Botrytis cinere) [27]. In generl, these two moths re controlled y the ppliction of insecticides, ut mting disruption hs een widely implemented over the lst decde, nd, tody, there re severl types of pheromone dispensers ville on the mrket [8, 28, 29]. In this study, we present generic pproch on how to construct nd test smll field cges tht permit n initil evlution of newly developed pheromone dispensers under stndrdised semifield conditions. The first step in the development of such field cge consisted of the construction of prototype. In secondstep, the efficiency of the prototype ws exmined nd its design ws refined. Finlly, the effects of vrying the numer of exposed insects nd the durtion of their exposure were exmined. 2. Mterils nd Methods 2.1. Study Site. Field trils were conducted in three different vineyrds round Nyon, Switzerlnd. The distnce etween them ws etween 5 nd 1 meters, nd they were ll three out 3 hectres in size Pheromone Dispensers. Commercilly ville Isonet- LE nd pheromone dispensers mnufctured y Shin-Etsu Chemicl Co. Ltd. (Tokyo, Jpn) were used. dispensers contined totl of 182 mg (E, Z)- 7,9-dodecdienyl cette (=E7, Z9-12:Ac) nd 182 mg (Z)- 9-dodecenyl cette (=Z9-12:Ac), the principl components of the pheromone lend of L. otrn nd E. miguell, respectively. dispensers contined 159 mg of E7, Z9-12:Ac ut only.4 mg Z9-12:Ac. Both dispensers re registered in Switzerlnd ginst E. miguell nd L. otrn, nd they were oth deployed t the recommended density of 5 per hectre Insects. Loesi otrn nd E. miguell used in this study originted from permnent lortory culture t Agroscope Chngins-Wädenswil. Moths were rered on semirtificil diet [3] in climte chmer (16 : 8 h L : D cycle, 7 ± 1% RH nd 22 C). Ten dys fter egg htch, corrugted crdord strips were plced in the rering oxes (19 9 8cm) to fford lrve plce to pupte. Pupe were sexed, nd mles nd femles were seprted. After emergence, dults were trnsferred into cylindricl plstic oxes (Ø = 1.5cm, h = 15 cm), where they hd free ccess to 1% sucrose solution. For the next two to four dys, moths were stored in room t mient temperture nd nturl photoperiod. After this, couples of L. otrn or E. miguell ged etween 3 nd 5 dys old were exposed in the field cges. Moths were lwys relesed into cges t the end of the fternoon nd were recovered in the morning. Moths collected were killed nd plced in 7% ethnol. Insect exposures were only mde when night temperture ws ove 13 C nd no precipittion ws forecsted [26] Field Cges Deployed with Pheromone Dispenser. The gol of the first field tril ws (1) to exmine if grpe

3 3 moths mte inside of smll insect field cges nd (2) to test if these cges re suited to mesure the effect of sex pheromones on mting. The core of these field cges consisted of cuic metl frme of 35 cm side length. The frme ws covered with cotton tissue ( µm mesh). Cges were opened nd closed y knotting of the tissue on one side of the cge, nd they were set up in three differently treted vineyrds. The first two vineyrds were either equipped with or pheromone dispensers nd the third vineyrd served s n untreted reference. Two field cges were set up per vineyrd in the middle of the folige out one meter from the ground. In ddition, pheromone dispenser ws fixed in the centre of ech cge in the two pheromone-treted vineyrds. Between July nd August 6, five couples of L. otrn or E. miguell were exposed simultneously in these field cges for one night. All three tretments were repeted over 12 different nights for L. otrn nd 1 different nights for E. miguell Field Cges Deployed without Pheromone Dispenser. The im of the second field tril conducted in the summer 6 ws to test if field cges not contining dispensers were n effective mens of compring mting disruption in the field. The tril ws set up in the sme vineyrds nd in the sme cges ( cm, mesh size = µm) s descried ove. However, no pheromone dispensers were plced in the cges instlled in the vineyrds treted with the or pheromone dispensers nd the nerest dispenser ws 4 meters wy. Once gin five couples of L. otrn or E. miguell were exposed in the cges for one night. Ech tretment ws repeted etween 5 to 11 nights for L. otrn nd 4 nights for E. miguell Refinement of Field Cge Tissue. With the im to improve the flow of ir into the field cges, the mesh size of the tissue covering the cges ws incresed. The cuic metl frmes of 35 cm side length were covered with polyester mosquito net of 15 µm mesh size. In ddition, cges were modified for ccess on one side y Velcro strip. The refined cges were set up in three vineyrds. Two vineyrds were either equipped with or pheromone dispensers nd the third vineyrd served s reference. Two field cges were put up in the middle of the folige per vineyrd, nd no pheromone dispensers were deployed within the cges. Once gin dispensers were t lest 4 meters wy of the cges. From June to August 7, five couples of L. otrn or E. miguell were exposed in these refined field cges for single night. Tretments were repeted on 28 nd 26 different nights for L. otrn nd E. miguell,respectively Refinement of the Durtion of Insect Exposure. For further refinement of the insect field cge method, the optiml length of time of insect exposure ws tested. In 8, cges of the sme type s used in the previous yer ( cm, mesh size = 15 µm) were set up in three differently treted vineyrds, tht is, two vineyrds either equipped with or dispensers nd third served s reference. Six field cges were instlled in ech vineyrd, nd no pheromone dispensers were deployed within cges. Only E. miguell ws tested. Between My nd June 8, five couples were exposed in cges for either one, two, or three nights. Ech tretment ws repeted five times Refinement of the Numer of Insects Exposed. To find the optimlinsectdensitywithinfieldcges,1,2,5,8,12,nd couples of E. miguell were exposed within single cge. For more ccurte ssessment of the ctul mting success t the two lowest insect densities, one nd two couples of E. miguell were exposed simultneously in three nd two cges, respectively. Therefter, dt were pooled nd the rithmetic mens of the proportion of mted femles were clculted for ech simultneously exposed density. The experiment ws conducted in the sme cges ( cm, mesh size = 15 µm, without ny dispensers within cges) nd in the sme vineyrds (, Isonet L-Plus, nd reference) s in the previous trils for ssessing the optiml durtion of insect exposure. Once gin only E. miguell wstestedndcoupleswereexposedforone night. Between My nd June 8, the six tretments were repeted four times Assessment of Mting Disruption. To determine the mting sttus of preserved femles, their urs copultris were dissected to confirm the presence or sence of spermtophores. To extrct the urs copultris, the femle domen ws degresed in 12% KOH solution of C. This process took 5 nd 1 minutes for L. otrn nd E. miguell, respectively. Therefter, the domen ws immersed in deminerlised wter for 1 minutes nd then rinsed for 5 minutes with 7% ethnol. The urs copultris ws crefully extrcted from the degresed domen under the inoculr. When t lest single spermtophore ws present, femles were clssified s mted Sttisticl Anlysis. Dt for L. otrn nd E. miguell were nlysed seprtely. The proportion of femles mted per tretment nd replicte ws rcsine-squre-roottrnsformed nd treted s the dependent vrile, wheres dte of exposure, pest control scheme (=, Isonet L- Plus, nd reference), nd durtion of exposure were treted s nominl independent vriles. Except for the experiment exmining the numer of relesed insect couples, ll trils were nlysed seprtely y either one-, two-, or threewy ANOVA. The experiment ssessing the effect of insect density in field cges ws nlysed y two-wy ANCOVA. The proportion of femles mted ws the dependent vrile, wheres dte of exposure nd type of pheromone dispenser were treted s fctors nd numer of exposed couples ws included in the model s covrite. For ll sttisticl tests, mens of pest control scheme nd durtion of exposure were compred pirwise with Tukey HSD post hoc tests. The fulfilment of model ssumptions ws checked y visul inspection of the distriution of residuls for every sttisticl test conducted. Throughout the text, mens re given ± SD.

4 4 (9 µg/dy) (75 µg/dy) Vineyrd (7 µg/dy) ( µg/dy) Vineyrd () () Figure 1: Percentge of mted () L. otrn nd () E. miguell femles in field cges (mesh size = µm) contining pheromone dispenser. The nottion µg/dy represents the pproximte dily emission rte of pheromone dispensers for () L. otrn nd () E. miguell. Pest control schemes with different letters re significntly different (P <.5); dt re untrnsformed; rs = 1 SE. 3. Results 3.1. Field Cges Deployed with Pheromone Dispenser. One hundred nd seventy-eight of the 1 exposed L. otrn femles were recovered nd dissected. The two-wy ANOVA reveled tht the dte of exposure hd no effect on mting (F 11; 22 = 1.62, P =.1), ut there ws significnt effect of pest control schemes (F 2; 22 = 71.82, P <.1, Figure 1()). Significntly more femles were mted in the reference vineyrd compred to the two vineyrds equipped with pheromone dispensers. However, there ws no sttisticl difference in the effectiveness of nd dispensers. For E. miguell, 134 of the 135 exposed femles were recovered. Wheres the dte of exposure only tended to ffect mting (F 9; 15 = 2.15, P =.92), the type of control scheme hd significnt effect (F 2; 15 = 9.97, P =.2, Figure 1()). Significntly fewer femles were mted in the -equipped vineyrd thn in the reference or the -treted vineyrd, nd there ws no significnt difference etween the reference vineyrd nd the one treted with dispensers emitting lower mount of Z9-12:Ac. Overll, 99% of exposed femles were recovered nd 73.6 ± 27.9% of femles exposed in the reference vineyrd were mted. Thus, grpe moths re cple to mte inside field cges. Moreover, cges seemed lso to e suited for ssessing the effectiveness of pheromone dispensers Field Cges Deployed without Pheromone Dispenser. 97% of L. otrn nd E. miguell femles exposed (N = 195) were recovered nd dissected. The one-wy ANOVA showed tht pest control schemes hd significnt effect on the mting sttus of L. otrn (F 2; 24 = 12.82, P<.1). The proportion of femles mted ws significntly higher in the reference vineyrd thn in the vineyrds equipped with either the or dispensers, tht is, 89.1 ± 13.8%,. ± 14.1%, nd 64.1 ± 13.2%, respectively. The two mting disruption tretments did not ffect mting y E. miguell (F 2; 9 =.43, P =.665). The proportion of mted femles ws 42.5±43.5%, 22.5±26.3%, nd 26.3 ± 25.% in the reference,, nd Isonet L-Plus treted vineyrd, respectively. Without pheromone dispenser in cges covered with dense cotton tissue, mting in E. miguell wslessdisrupted Refinement of Field Cge Tissue. More thn 95% of femles exposed (N = 81) were recovered nd dissected from the cges covered with the mosquito net of 15 µm mesh size. The two-wy ANOVA showed tht dte of exposure (F 27; 54 = 5.93, P<.1) s well s pest control schemes (F 2; 54 = 23.63, P <.1, Figure 2()) hd significnt effect on the mting sttus of L. otrn. The proportion of mted femles ws significntly higher in the reference vineyrd compred to the vineyrds equipped with either or dispensers. There ws no sttisticl difference etween the two dispenser types. For E. miguell, the dte of exposure only tended to ffect mting (F 25; 5 = 1.53, P =.99), wheres the type of control scheme hd significnt effect (F 2; 5 = 13.48, P <.1, Figure 2()). Significntly fewer femles were mted in the two pheromone-treted vineyrds thn in the reference. Furthermore, there ws no sttisticl difference in the effectiveness etween the lower chrged nd the more hevily chrged dispensers Refinement of the Durtion of Insect Exposure. 92% of E. miguell femles (N = 225) exposed were recovered. The three-wy ANOVA showed tht the dte of exposure (F 4; 32 = 1.56, P <.1) nd the pest control scheme (F 2;32 = 44.45, P <.1) hd significnt effect on the mting sttus of femles, wheres the durtion of exposure (F 2; 32 =.38, P =.684) nd the interction of the control scheme nd the durtion of exposure did not ffect mting (F 4; 32 =.82, P =.522, Figure 3). The proportion of mted femles ws significntly higher in the reference vineyrd thn in the two vineyrds equipped with pheromone dispensers. Moreover, the more hevily chrged dispensers disrupted mting significntly etter thn the lower chrged dispensers. Overll, one night of insect exposure in our cges ppered to e sufficient to evlutethe effectiveness of pheromone dispensers.

5 5 (9 µg/dy) (75 µg/dy) Vineyrd (7 µg/dy) ( µg/dy) Vineyrd () () Figure 2: Percentge of mted () L. otrn nd () E. miguell femles in field cges (mesh size = 15 µm) contining no pheromone dispenser. The nottion µg/dy represents pproximtely the dily emission rte of pheromone dispensers for () L. otrn nd () E. miguell. Pest control schemes with different letters re significntly different (P <.1); dt re untrnsformed; rs = 1 SE. 1 night 2 nights 3 nights Durtion Tle 1: ANCOVA tle on the effectofdteofexposure,numer of exposed couples, nd mting disruption control scheme on the mting sttus of E. miguell femles. Source of vrince df Sum of Sq F vlue P Dte of exposure Numer of exposed couples (=NEC) <.1 Pest control scheme (=PCS) <.1 NEC PCS Error (7 µg/dy) ( µg/dy) Figure 3: Effect of the durtion of insect exposure on the percentge of E. miguell femles mted in field cges (mesh size = 15 µm, contining no pheromone dispenser). The nottion µg/dy represents the pproximte dily emission rte of pheromone dispensers for E. miguell; dt re untrnsformed; rs = 1SE Refinement of the Numer of Insects Exposed. 97% of ll femles of E. miguell (N = 576) exposed were recovered nd dissected. The two-wy ANCOVA reveled tht the dte of exposure tended to ffect mting nd tht the numer of exposed couples, the pest control scheme, nd the interction of the ltter two significntly ffected the mting sttus of femles (Tle 1). The significnt interction etween the numer of exposed couples nd pest control schemes indictes tht the slopes differed significntly mong the three pest control schemes (Figure 4). The significnt interction lso implies tht the two min effects hve to e interpreted with cution. Nonetheless, it cn e sid tht the proportion of femles mted incresed with the numer of exposed couples nd tht significntly fewer femles were mted in the two vineyrds equipped with pheromone dispensers thn in the reference vineyrd, in prticulr t low insect densities. At high insect densities, higher chrged dispensers Numer of couples exposed (7 µg/dy) y =.36x , R 2 =.1, P =.67 y = 2.58x +1.26, R 2 =.67, P<.1 y = 1.53x +.86, R 2 =.55, P<.1 ( µg/dy) Figure 4: Effect of the numer of couples exposed on the percentge of E. miguell femles mted in field cges (mesh size = 15 µm, contining no pheromone dispenser). The nottion µg/dy represents the pproximte dily emission rte of pheromone dispensers for E. miguell; dt from the three insect control schemes were fitted with liner regression models. seemed to disrupt mting etter thn lower chrged Isonet L-Plus dispensers. Overll, the exposure of n intermedite density of eight couples seems to e good compromise etween the ility to identify significnt differences etween control schemes nd n extensive increse in lour.

6 6 4. Discussion Our study shows tht smll insect field cges could constitute vlule sset for preliminry evlution of pheromone dispensers under stndrdised semifield conditions. The proportion of mted femles in cges ws significntly reduced in plots equipped with pheromone dispensers compred to untreted sites. Thus, the exposure of few insect couples for short period of time cn lredy provide useful insights into the potentil efficcy of different mting disruption schemes. Considering the development process outlined here, it should e possile to dpt our cges to other pest systems. Below we first discuss the stepwise development of these insect field cges nd then highlight implictions of our work for the iotechnologicl industry Development nd Refinement of Field Cges. As first step, we constructed prototype of field cge. We then tested if grpe moths mte within these cges nd if these cges could e suited to mesure the effect of sex pheromone dispensing on pest insect mting success. The dissection of femles reveled tht insects mte without difficulty within the field cges. The cges lso llowed to mesure significnt differences in the mting success of femles exposed to sex pheromones compred to controls. This finding ws chieved even though the insect density within cges ws extremely high nd rndom encounters could e frequent conditions tht re generlly ssumed to e unfvourle for mting disruption [31]. Nonetheless, our oservtion is in line with tht of others [24, 25] nd confirms tht mting disruption schemes my reduce insect mting even t high pest densities where rndom encounters re frequent. A ig dvntge of our smll prototype (.4 m 3 ) compred to the more commonly used lrger field cges, for exmple, 8 m 3 [15], is tht they interfere little with culturl prctices such s the pssge of trctors nd the mintennce of the vine. Secondly, the effectiveness of mting disrupting cn e ssessed y exmintion of femle s reproductive orgns. This exmintion provides the dvntge of direct mesurement of the impct of pheromone dispensing on mting nd not just n indirect effect on mte finding y mles s mesured y exposing pheromone-ited trps within lrger field cges. In second step, we withdrew pheromone dispensers from the inside of the field cge to test if the method would lso e suited to mesure the effect of previling sex pheromones in the vineyrd. Unfortuntely, mting ws less disrupted, indicting tht the technique of using cge without dispenser plced inside my hve limittions. Additionl nlyses showed tht the tissue of µm mesh covering the prototype reduced ir flow into cges y lmost 9%, wheres mosquito net of 15 µm meshsize hd 75% ir permeility [19]. The tissue ws therefore replced y the more ir permele mosquito net. Therefter, the proportion of femles mted ws significntly lower within cges surrounded y pheromone dispensers compred to femles similrly exposed in the reference vineyrd. Thus, the refined cges with the more permele mosquito net ppered suitle for mesuring the effect of the previling sex pheromone regime on mting disruption. Finlly, we refined the durtion of insect exposure nd the numer of insects exposed. Our trils reveled tht mting did not significntly increse with the length of exposure of insects within the cges. The exposure of insects of the right ge for one night is sufficient to evlute the effectiveness of different mting disruption schemes in grpe moths. However, the proportion of femles mted incresed with the numer of exposed couples. Wheres high densities (>12 couples/cge) demnd considerly greter mount of work in order to rer, expose, nd dissect insects, differences etween the two pheromone tretments used here were unverifile t low moth densities (<5 couples/cge). This is in ccordnce with Vick et l. [32] nd Plniswmy et l. [24] who lso oserved only smll differences etween mting disruption schemes t low pest densities. The exposure of out eight couples in the field cges seems therefore to e optiml. This corresponds to grpe moth density of 8 couples per hectre (B. Bloesch, personl communiction), pest pressure tht is extremely high nd tht hs rrely een oserved in commercil vineyrds. To conclude, the exposure of eight couples within our field cges during wrm nd rinless night llows to compre different pheromone mting disruption schemes trgeting grpe moths under stndrdised semifield conditions Implictions for the Biotechnologicl Industry. Smll insect field cges offer fst, simple, chep, nd relile method for preliminry ssessment of pheromone-sed control methods. Compred to clssicl field trils, pest density cn e controlled nd the miniml size of tril plots cn e reduced. Severl temporl repetitions cn e ccomplished over reltively short period of time, fcilitting sttisticlly sound nlyses. Furthermore, the effectiveness of newly developed pheromone dispensers cn e redily compred to conventionl dispensers s well s to untreted plots. However, it should e noted tht mles cnnot follow flse plumes within smll cges. As consequence, smll insect field cges only llow to evlute nd compre the noncompetitive mechnisms of mting disruption. Thus, findings otined under these stndrdised semifield conditions cnnot replce the finl evlution of mting disruption schemes in commercil fields, ut they my nonetheless help to predict the vlue of setting up more expensive lrge-scle field trils. Following the stepwise development process outlined ove, it should e possile to uild field cges specificlly dpted to different pest systems. Cges re reltively chep to construct, nd the criticl step in their development is the determintion of cge size nd the optiml numer of insects exposed. The mesh size of the tissue covering the cge should e chosen s lrge s possile to ssure mximl ir exchnge etween the cge nd the environment, nd the durtion of insect exposure should e kept not longer thn required for stisfctory degree of mting in the untreted control.

7 7 5. Conclusions Smll insect field cges provide new perspectives for the ssessment of pheromone dispensing on mting nd my e of vlue in pplied s well s fundmentl reserch. For exmple, with these cges, the effectiveness of different formultion types (e.g., spryle microcpsules, hndpplied dispensers, erosol puffers) nd of new pheromone lends (e.g., plnt voltiles) might possily e evluted nd compred. Secondly, our cges could lso e used to test for the miniml density of dispensers required per unit re or the optiml numer of point sources in the crop (Kehrli unpulished dt). And, thirdly, smll field cges my help to investigte the underlying mechnisms of mting disruption in short-distnt flight [13, 14, 33]. Thus, smll field cges with insect couples offer simple nd fst method for evluting mting disruption under stndrdised semifield conditions, nd they my therefore e welcome sset to the iotechnologicl industry developing this environmentl friendly pest control technique. Acknowledgments The uthors thnk especilly Crine Vergely, Thoms Steinger, Philippe Jenourquin, Denis Psquier, Thoms Degen, Jcques Derron, nd Steve Breitenmoser for stimulting discussions nd prcticl ssistnce s well s Monique Thorimert, Mrtine Rhyn, nd Susnne Tgini for help with the rering of insects. They lso thnk Andermtt Biocontrol AG for the provision of pheromone dispensers nd the winegrowers in the region of Nyon, Switzerlnd, for their collortion. This reserch ws funded y the Ntionl Centre of Competence in Reserch (NCCR) Plnt Survivl t the University of Neuchâtel, reserch progrm of the Swiss Ntionl Science Foundtion. s [1] G. J. Devine nd M. J. Furlong, Insecticide use: contexts nd ecologicl consequences, Agriculture nd Humn Vlues, vol. 24, no. 3, pp , 7. [2] D. Zeljezic, A. L. Vrdoljk, N. Kopjr, B. Rdic, nd S. Milkovic Krus, Cholinesterse-inhiiting nd genotoxic effects of cute crofurn intoxiction in mn: cse report, Bsic nd Clinicl Phrmcology nd Toxicology, vol. 13, no. 4, pp , 8. 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