Y. de Ladurantaye 1, M. Khelifi 1*, C. Cloutier 2 and T. A. Coudron 3

Transcription

1 Short-term storge conditions for trnsport nd frm delivery of the stink bug Perillus biocultus for the biologicl control of the Colordo potto beetle Y. de Ldurntye 1, M. Khelifi 1*, C. Cloutier 2 nd T. A. Coudron 3 1 Deprtment of Soil Science nd Agri-Food Engineering, Universite Lvl, Quebec, Quebec, G1V0A6 Cnd; 2 Deprtment of biology, Universite Lvl, Quebec, Quebec, G1V0A6 Cnd; nd 3 University of Missouri Columbi, USDA, Columbi, USA. *Emil: mohmed.khelifi@fs.ulvl.c. de Ldurntye, Y., Khelifi, M., Cloutier, C. nd Coudron, T. A Short-term storge conditions for trnsport nd frm delivery of the stink bug Perillus biocultus for the biologicl control of the Colordo potto beetle. Cndin Biosystems Engineering/Le ge nie des biosyste` mes u Cnd The most common method of controllingthe Colordo potto beetle (CPB), Leptinotrs decemlinet (Sy), is the ppliction of chemicl insecticides. Severl lterntives to chemicl insecticides hve been proposed, but re in generl not yet pplicble for current commercil scle production. One of them is ugmenttive biologicl control using nturl insect predtor. Consideringthe need of more sustinble griculture, the objective of this study ws to develop dequte short-term storge conditions for the second instr nymphs of the predceous penttomid, Perillus biocultus. This instr hs previously been found to be suitble for relese to control eggs nd erly instrs of the CPB in the springon pottoes. Mny lbortory tests on P. biocultus second instr nymphs hve been crried out to investigte the followingstorge conditions: ir,, nd period of storge. Results show tht storge s within the rnge of 9 to 15 o C nd (16:8 h L:D nd 0:24 h L:D) did not significntly ffect the survivl nd post-storge development of P. biocultus nymphs stored for periods of 2 to 8 d. Compred with shorter periods (i.e., less thn 8 dys), storge for 10 dys significntly reduced the survivl rte by bout 20%. Development time to the next instr t 208C followingstorge ws not significntly ffected by experimentl conditions, lthough development ws slightly fster t 158C for 10 dys of storge. Future studies should investigte the dispersl nd predceous performnce of P. biocultus followingvrious combintions of storge conditions. Keywords: Storge,,, Colordo potto beetle, chemicl insecticides, lterntive, biologicl control, Perillus biocultus. Les insecticides chimiques sont courmment utilise s pour controˆ ler le doryphore de l pomme de terre, Leptinotrs decemlinet (Sy). Plusieurs lterntives ` l utilistion des insecticides chimiques ont e té explore es, mis demeurent inpplicbles à grnde échelle. Prmi ces lterntives, on distingue le controˆ le biologique ugmenttif utilisnt des pre dteurs nturels. Dns l optique d une griculture durble, l objectif de ce trvil de recherche e tit de de terminer les conditions de qutes d entreposge des nymphes de deuxie` me stde lrvire du pre dteur Perillus biocultus. Il de jà e te de montre que ce stde lrvire en prticulier convient bien ` l distribution u chmp pour controˆ ler les æufs et les petites lrves de doryphore sur les plnts de pomme de terre u printemps. Plusieurs expériences sur des lrves de deuxie` me stde de Perillus biocultus ont e te re lise es en lbortoire pour exminer les conditions d entreposge suivntes: tempe rture de l ir, photope riode et dure e d entreposge. Les re sultts ont de montre que les tempe rtures d entreposge entre 9 o C et 15 o C et une photope riode de (16: 8 h L: N et 0:24 h L: N) n ont ps ffecte de fc on significtive l survie et le de veloppement pre` s l entreposge des nymphes de Perillus biocultus et ce pour des pe riodes d entreposge de deux à huit jours. Compre ` des pe riodes plus courtes, l entreposge pendnt 10 jours réduit l survie d environ 20%. Le temps de de veloppement ` 208C pour tteindre le troisie` me stde suite à l entreposge n ps e te significtivement ffecte pr les conditions expe rimentles, bien que le de veloppement it e te lége` rement plus rpide ` 158C pendnt 10 jours d entreposge. Comme trvux futurs, il ser intéressnt d exminer l dispersion et l performnce de pre dtion de Perillus biocultus suite ` un tel entreposge sous diverses conditions. Mots clés: Entreposge, tempe rture, photope riode, doryphore de l pomme de terre, insecticides chimiques, lterntive, controˆ le biologique, Perillus biocultus. INTRODUCTION The Colordo potto beetle (CPB), Leptinotrs decemlinet (Sy) (Coleopter: Chrysomelide) is the most importnt defolitor of potto, Solnum tuberosum (L.), in Cnd (Hre 1980; Boiteu et l. 1992; Howrd et l. 1994), the United-Sttes (Rdcliffe et l. 1993), nd mny countries in Europe nd Asi (Jolivet 1991). In North Americ, ttention hs been focused for bout 25 yr on both the incresingthret of the CPB resistnce to chemicl insecticides nd the development of other lterntives (Boiteu et l. 1987; Duchesne nd Boiteu 1995; Cloutier et l. 2002). Chemicl insecticides hve often been efficient in controllingthe CPB on short-term bsis. Since the CPB evolved resistnce to DDT in the 1950s, it lso cquired resistnce to mny other chemicl insecticides (Forgsh 1981; Mrtel 1987; Boiteu et l. 1987; Whlon et l. 1993). Currently, resistnce to imidcloprid, recently introduced insecticide tht is widely used to control this insect pest, hs been reported 4.1

2 (Mot-Snchez et l. 2006; Alyokhin et l. 2007). The over use of chemicl insecticides cn led to environmentl nd helth problems for people livingin regions where potto is intensively cultivted. For decdes, biologicl control usingrthropod predtors nd prsitoids hs been investigted s n lterntive to chemicl insecticides to control CPB popultions. To dte, most of the developed lterntives hve not been efficient enough or difficult to pply on commercil scle. Reltively recent invsive pests, such s the CPB in Cnd, often hve few coevolved nturl enemies nd need specific control mngement. More specific nturl predtors of CPB eggs nd lrve hve received prticulr ttention. The two-spotted stink bug, Perillus biocultus (Fbricius) (Hemipter: Penttomide), ntive to North Americ, is mongthe most specilized insect predtors of the CPB (Knight 1923, 1952; Sint-Cyr nd Cloutier 1996; Hough-Goldstein et l. 1993; Cloutier et l. 2002) with potentil to ttck eggs, ll lrvl instrs, nd even dults of the CPB. Perillus biocultus is predceous on other chrysomelid lrve, cterpillrs, nd other insect herbivores, but it hs most frequently been recorded s predtor of the CPB. The biologicl control of the CPB using P. biocultus hs been efficient in smll-scle relese trils nd in cge studies in Europe (Jermy 1980), Cnd (Cloutier et l. 2002), nd the United Sttes (Hough-Goldstein nd Keil 1991; Biever nd Chuvin 1992, 1992b; Hough-Goldstein nd Whlen 1993; Poprwski et l. 1997). In Quebec, Cloutier nd Buduin (1995) nd Cloutier nd Jen (1998) experimentlly used P. biocultus nymphs to control the CPB nd observed its predtion ctivity under rnge of s. In ugmenttive releses, rtio of three P. biocultus second instr nymphs (Fig. 1) to one CPB egg cluster during spring egg lying provided dequte folige protection. The mrked preference of P. biocultus for the CPB my imply miniml risk of non-trget predtion (Sint-Cyr nd Cloutier 1996). The field studies of Sint-Cyr nd Cloutier (1996) confirmed the pre-emptive strtegy tht Fig. 1. The two spotted second instr stink bug, Perillus biocultus (Fb.), feeding on CPB egg. would consist of relesing P. biocultus nymphs s soon s springcpb eggmss density cn be monitored nd used to estimte the potentil for dmge to potto crops by first genertion resident beetles. In this cse, it would be possible to sve on the tretment cost by more precise mngement of the predtors. Compred with eggs nd first instrs, second instr P. biocultus would be more suitble for mss relese becuse of their immedite predtion potentil on smll CPB instrs, especilly the egg clusters nd newly htched lrve, nd predtor dispersl cpbilities in the field, which intercts with CPB density through predtor hunger nd stition (Lchnce nd Cloutier 1997; Cloutier 1997). On the other hnd, eggs nd first instr nymphs re more frgile, but they do not need to feed, nd hence re potentilly esier to keep live duringstorge nd pre-relese mngement. However, their relese synchroniztion with erly CPB instrs would be more difficult becuse of the offset time before developingtheir predtion bility, which is mnifest only fter moltingto the second instr (Hough-Goldstein et l. 1996). Also, they re possibly more vulnerble to predtion nd mny other potentil risks. Duringour lbortory experimenttion, we observed tht the htching rte of eggs from mss rered femles is vrible, even under lbortory conditions. Thus, more eggs would need to be relesed to compenste potentil loss. Hough-Goldstein et l. (1996) found tht eggs relesed directly on plnts survived poorly, wheres those plced in refuge gve s good control of CPB s second instr nymphs tht were lso relesed in refuge. For efficient use of predtors for biologicl control in lrge fields, proper storge nd trnsport techniques re vitl from the production/reringfcility until their field distribution. Trnsporttion over longdistnces nd vrible s mke the storge of suitble predtor instrs essentil until they re relesed in the field. At cold s, insect metbolism nd ctivity slow down, which is desirble, but, over time, cold stress is potentilly hrmful, s shown for other insect biologicl control gents (e.g., Colinet et l. 2006). Cold storge is helpful in directly delyinggrowth nd development of the insect, nd lso importntly in this prticulr cse in preventingpotentil cnniblism. De Clercq nd Degheele (1993) found tht nymphs of two relted Podisus stinkbugs were less resistnt to cold storge thn eggs nd dults. Nymphs of first to fourth instrs hrdly survived 57 dys t s below 108C lthough fifth instr nymphs were more tolernt. Their work suggested tht P. biocultus second instr nymphs might not survive cold storge or would do so t substntil fitness costs. Knowingthe storge limits of second instr nymphs of P. biocultus should help to estblish suitble conditions for their trnsport, storge, nd relese in commercil potto fields to control the CPB nd subsequently develop n pproprite delivery system. The min focus of this reserch ws therefore to exmine conditions for P. biocultus second instr nymphs tolernce to shortterm (12 weeks) cold storge. 4.2 LE GÉNIE DES BIOSYSTÈMES AU CANADA DE LADURANTAYE ET AL.

3 MATERIALS nd METHODS Perillus biocultus Perillus biocultus eggs were collected directly from colony mintined on n rtificil diet for bout 20 genertions t the Biologicl Control of Insects Reserch Lbortory, Columbi, MO, USA. These eggs were mixed with vermiculite in smll continers nd then shipped by ir in box with newspper nd cold pck to keep them cool. On their rrivl t our lbortory (De prtement de biologie, Universite Lvl, QC, Cnd), the eggs were plced in ventilted plstic Petri dishes (15 cm) over lyers of dmp pper towelling. Ech plstic Petri dish ws plced in wlk-in growth chmber (Model PGW-36, Conviron, Winnipeg, MB, Cnd) t 20918C, 65910% RH, nd of 16:8 h (light:drk) nd to prevent desicction, they were gently spryed dily with distilled wter. Colordo potto beetle A CPB colony ws lso mintined in greenhouse to serve s food for the predtors. Colordo potto beetle eggs lid on potto leves were picked dily nd kept in refrigertor t 48C until used nd for mximum of 9 dys. The stored eggs served s food for the second instr P. biocultus nymphs under storge conditions, especilly duringsubsequent development to instr three t 208C (see below). Experimentl design nd procedure A split-split-plot design ws used to test three fctors: (1) ir s the min plot (T) with three levels (9, 12, nd 15918C), (2) in the subplot (Ph) with two levels (16:8 h L:D vs. 0:24 h L:D), nd (3) period of storge in the sub-subplot (P) with five levels (2, 4, 6, 8, nd 10 dys), for totl of 30 fctor combintions (3 T2 Ph 5 P). The bsic design consisted of three growth chmbers, ech held t one of the three experimentl s. Photoperiod within ws implemented s two subdivisions in ech chmber, where the no light (0 L24 D h) tretment ws relized by fully shdingthe insects. The observtion units consisted of smll cges mde of ventilted plstic Petri dishes (15 cm), ech one contining5 or 10 nymphs, ech unit being rndomly ssigned mong tretment combintions. Since we hd limited number of nymphs, we used two nymph densities duringthe experimenttion: 10 nymphs for the trils t the criticl storge of 98C nd 5 nymphs elsewhere. As found by De Clercq nd Degheele (1993), survivl of young Podisus nymphs t s below 108C ws reduced, nd therefore 98C ws chosen s the minimum experimentl for P. biocultus. Cloutier nd Buduin (1995), estimted from field observtions tht 128C is ner the minimum for predtion ctivity, nd finlly 158C ws lso included for modellingpurposes. The technique used for shding(keep insects in the drk for the whole storge period in the 024 h tretments) ws to plce cged insects underneth two upside down plstic flower pots (Fig. 2), so tht their drip holes were not ligned. In this wy, nymphs were not exposed to light, but ventiltion ws possible to keep the sme ir conditions inside nd outside the pots. An electronic thermistor nd photometer were used to check ir nd drkness conditions, respectively, inside cges nd pots. Different rrivls of P. biocultus eggs were considered s different blocks for experimentl design purposes (N three blocks). Newly rrived eggs were held in growth chmber t 208C nd regulrly monitored until htching. Therefter, nymphs were observed once dily until they molted to the second instr. Newly molted second instrs (024 h old) were rndomly collected nd combined in groups of 5 or 10 individuls nd plced in the Petri dishes (Fig. 2b). The nymphs were continuously supplied with CPB eggs nd wter throughout the storge periods. At the end of storge tretment, the number of survivors ws recorded nd they were trnsferred to new growth chmber set t 208C nd monitored dily for survivl nd Fig. 2. Experimentl setup: () technique used to keep cged stinkbug nymphs in continuous drkness in the no light (024 h) tretments, (b) newly molted Perillus biocultus second instr nymphs plced in disk-vented plstic Petri dishes with wter-soked dentl cotton nd CPB eggs on piece of potto lef. 4.3

4 development to instr 3, s determined by the presence of exuvie shed t moulting. For post-storge conditions, 208C ws selected s close to optiml for P. biocultus development nd predtion on CPB (Lchnce nd Cloutier 1997). The sme food/wter combintion ws provided s during the storge period t rte of one egg cluster per unit. Sttisticl nlysis An ANOVA ws performed on the dt usingthe Proc Mixed nd Proc Glimmix procedures of SAS softwre (SAS Institute, Inc. 2003). When ANOVA results were significnt, posteriori pirwise comprisons were done usingprotected LSD, with the Bonferroni correction to djust experimentwise significnce vlues. The ngulr trnsformtion [rcsin â (P/100)] ws pplied to the survivl dt to improve homogeneity of vrinces (Steel nd Torrie 1980), with number of observed nymphs per Petri dish (5 or 10) beingincluded s covrite in the ANOVA. RESULTS nd DISCUSSION Effects of on the nymphs survivl during storge Photoperiod hd no significnt effect on the survivl duringstorge (F 1, , P0.6185) (Tble 1) or the survivl up to instr 3 (F 1, , P0.8367), nd neither ws involved in ny significnt interctive effect with or storge period (Tble 1). The results suggest tht the young nymphs could be sfely kept in complete drkness with no for storge period of 10 dys or less nd t ny of the three experimentl s, which simplifies the storge process. Effects of storge nd durtion on survivl There ws no significnt effect of (F 2, , P ) on percent survivl to the end of storge, survivl being significntly ffected only by the storge period (F 4, , PB0.0001) (Tble 1). For the 10 dys storge period, significnt number of nymphs hd died (i.e., survivl rte of %) compred with those kept for 8 dys or less (Fig. 3). Similrly, there ws no significnt effect of rering on survivl to instr 3 (F 2, , P0.6534), with storge period beinglso significnt (F 4, , P0.0002). Overll, this suggests tht young nymphs could be successfully stored for pproximtely 1 week t ny of the tested s before relese. Effects of storge conditions on post-storge development After storge, the dditionl time required to complete the second instr t 208C ws recorded to determine ny storge effects on fitness, s mesured by the developmentl rte of P. biocultus nymphs. ANOVA results show tht overll second instr developmentl time to the third instr ws not significntly ffected by (F 1, , P0.4439) (Tble 2), nor were there ny significnt interctions mong experimentl fctors Tble 1. ANOVA results for the survivl dt fter storge. Source of vrition D.F. F Vlues PrF Block NS Temperture NS Block (Error1) 4 Photoperiod NS Temperture NS Error2 6 Storge period B *** Storge period NS Storge period NS Storge period NS Error3 46 Corrected totl 87 ***Significnt t PB0.05; NS, not significnt. (P] ). The highly significnt effect of storge period (F 2, , PB0.0001) (Tble 2), simply reflects the fct tht development time, s mesured here, includes the period of storge which ws experimentlly mnipulted. The slight mrginl effect of (F 2, , P ) (Tble 2) suggests tht some development did occur under storge t the higher s. Fig. 4 shows tht t 158C verge development time ws slightly shorter ( dys), compred with 98C nd 128C (verge development times of nd Survivl rte (%) Period of storge (dys) Fig. 3. Survivl of second instr Perillus biocultus nymphs for different storge periods. For ech period, dt were pooled cross rering s. Brs with the sme letter re not significntly different in multiple comprisons with the Bonferoni correction. b 4.4 LE GÉNIE DES BIOSYSTÈMES AU CANADA DE LADURANTAYE ET AL.

5 Tble 2. ANOVA results for the development time dt. Source of vrition D.F. F Vlues PrF Block NS Temperture NS Block (Error1) 4 Photoperiod NS Temperture NS Error2 6 Storge period B.0001*** Storge period NS Storge period NS Storge period NS Error3 45 Corrected totl 403 ***Significnt t PB0.05; NS, not significnt. 0.3 dys, respectively). Overll, the results indicte tht some development my occur under 158C over 10 dys of storge, with no obvious detrimentl effect of storge conditions on cpcity or time to rech the next instr. The storge limits of the second instr nymphs of P. biocultus were successfully investigted to optimize their storge nd trnsport conditions for n eventul relese in commercil potto fields, without ffectingtheir survivl. The storge conditions suggested in this study will slow the growth of the nymphs until their relese in the field. Cold s, in the rnge of 9 to 158C, will slow the predtors metbolism nd ctivity with no pprent hrmful stress. The results obtined lso show tht it is possible to keep the nymphs in drkness mking their storge nd trnsport esier by using common delivery boxes nd the existingrefrigerted chmbers once they hve been delivered to the frm. More importnt, orgnic frmers will be ble to order the required number of nymph predtors in dvnce from ny insect rering/distributing fcility nd keep them for up to t lest 1 week to coincide with the trgeted CPB instrs or until dequte wether conditions llow their relese in the field. CONCLUSIONS Bsed on the results of our experiments, short-term storge conditions of P. biocultus second instr nymphs cn be optimised by consideringthese fcts: - Storge s in the rnge of 9 to 158C did not significntly ffect the survivl of second instr nymphs kept for mximum of 8 dys under storge conditions. For 10 dys of storge, which ws the longest period tested here, nymphl survivl ws reduced by bout Totl development time (dys) Storge ( C) Fig. 4. Effects of the three s tested (9, 12, nd 158C) on the development time of the second instr nymphs to instr 3 (development time dt include the storge period). 20% nd thus the performnce of survivors might be expected to decline. - Storge s in the rnge of 9 to 158C did not significntly ffect totl time to the next instr, which included post-storge t 208C. But for storge t 158C, time to the next instr ws on verge 11.5 dys shorter thn t 9 or 128C, suggesting some development during storge. This must be considered for biocontrol purposes, especilly when predtor-prey synchroniztion is importnt. - For storge periods of 10 dys or less in complete drkness, the lck of did not significntly ffect survivl or development time to the next instr. Future studies investigting the predceous performnce of P. biocultus (i.e., dispersl nd predtion rte) followingstorge should be conducted to provide dditionl insight into potentil effects of storge nd id in designing prmeters tht will ssist in mximizing the use of this beneficil predtor in controllingcpb. ACKNOWLEDGEMENTS The uthors grcefully cknowledge the finncil support of the Nturl Sciences nd Engineering Reserch Council of Cnd (NSERC). The ssistnce of Mr. Getn Digle, Professionl Sttisticin, Deprtment of Mthemtics nd Sttistics, Universite Lvl, in nlyzingthe dt is gretly pprecited. REFERENCES Alyokhin, A., G. Dively, M. Ptterson, C. Cstldo, D. Rogers, M. Mhoney nd J. Wollm Resistnce nd cross-resistnce to imidcloprid nd thimethoxm 4.5

6 in the Colordo potto beetle. Pest Mngement Science 63: Biever, K.D. nd R.L. Chuvin Suppression of the Colordo potto beetle with ugmenttive releses of predceous stinkbugs. Journl of Economic Entomology 85: Biever, K.D. nd R.L. Chuvin. 1992b. Timingof infesttion by Colordo potto beetle (Coleopter: Chrysolelide) on the suppressive effect of field relesed stinkbugs (Hemipter: Penttomide) in Wshington. Environmentl Entomology 21: Boiteu, G., R.H. Prry nd C.R. Hrris Insecticide resistnce in New Brunswick popultions of the Colordo potto beetle (Coleopter: Chrysolelide). Cndin Entomologist 119: Boiteu, G., G.C. Misener, R.P. Singh nd G. Bernrd Evlution of vcuum collector for insect pest control in potto. Americn Potto Journl 69: Cloutier, C Fcilitted predtion through interctions between life stges in the stinkbug predtor Perillus biocultus (Hemipter: Penttomide). Journl of Insect Behvior 10: Cloutier, C. nd C. Jen Synergism between nturl enemies nd biopesticides : test cse usingthe stinkbug Perillus biocultus (Heteropter: Penttomide) nd Bcillus thuringiensis tenebrionis ginst Colordo potto beetle (Coleopter: Chrysolelide). Journl of Economic Entomology 91: Cloutier, C. nd F. Buduin Biologicl control of the Colordo potto beetle, Leptinotrs decemlinet (Sy) (Coleopter: Chrysolelide) in Quebec by ugmenttive relese of the two-spotted stinkbug Perillus biocultus (Hemipter: Penttomide). Cndin Entomologist 127: Cloutier, C., G. Boiteu nd M.S. Goettel Leptinotrs decemlinet (Sy), Colordo potto beetle (Coleopter: Chrysomelide). In Biologicl Control Progrmmes in Cnd , eds. P.G. Mson nd J.T. Huber, Wllingford, UK: CABI Publishing. Colinet, H., D. Renult, T. Hnce nd P. Vernon The impct of fluctutingtherml regimes on the survivl of cold-exposed prsitic wsp, Aphidius colemni. Physiologicl Entomology 31: De Clercq, P. nd D. Degheele Cold storge of the predtory bugs Podisus mculiventris (Sy) nd Podisus sgitt (Fbricius) (Heteropter: Penttomide). Prsitic 49: Duchesne, R.-M. nd G. Boiteu Insect pest control on potto: Development of sustinble pproch. Quebec: Ministe` re de l Agriculture, des Peˆ cheries et de l Alimenttion du Que bec. Forgsh, A.J Insecticides resistnce of the Colordo potto beetle, Leptinotrs decemlinet (Sy). In Advnces in potto pest mngement, eds. J.H. Lshomb nd R. Csgrnde, Stoudsburg, PA: Hutchinson Ross PublishingCo. Hre, J.D Impct of defolition by the Colordo potto beetle on potto yields. Journl of Economic Entomology 73: Hough-Goldstein, J. nd C.B. Keil Prospects for integrted control of the Colordo potto beetle (Coleopter: Chrysolelide) using Perillus biocultus (Hemipter: Penttomide) nd vrious pesticides. Journl of Economic Entomology 84: Hough-Goldstein, J. nd J. Whlen Inundtive relese of predtory stink bugs for control of Colordo potto beetle. Biologicl Control 3: Hough-Goldstein, J.A., G.E. Heimpel, H.E. Bechmnn nd C.E. Mson Arthropod nturl enemies of the Colordo potto beetle. Crop Protection 12: Hough-Goldstein, J., J.A. Jnis nd C.D. Ellers Relese methods for Perillus biocultus (F.), predtor of the Colordo potto beetle. Biologicl Control 6: Howrd, R.J., J.A. Grlnd nd W.L. Semn Diseses nd pests of vegetble crops in Cnd. Ottw, ON: The Cndin Phytopthologicl Society nd Entomologicl Society of Cnd. Jermy, T The introduction of Perillus biocultus into Europe to control the Colordo beetle Leptinotrs decemlinet. EPPO Bulletin 10: Jolivet, P Le doryphore mence l Asie Leptinotrs decemlinet Sy 1824 (Col. Chrysomelide). L Entomologiste 47: Knight, H.H Studies on the life history nd biology of Perillus biocultus Fbricius, includingobservtions on the nture of color pttern. 19th Report of the Stte Entomologist of Minnesot 1922: Knight, H.H Review of the genus Perillus (Heteropter: Penttomide) with description of new species. Annls of the Entomologicl Society of Americ 45: Lchnce, S. nd C. Cloutier Fctors ffecting dispersl of Perillus biocultus (Hemipter: Penttomide), predtor of the Colordo potto beetle (Coleopter: Chrysomelide). Environnementl Entomology 26: Mrtel, P Chemicl control nd resistnce development in potto pests. In Potto pest mngement in Cnd-Lutte contre les prsites de l pomme de terre u Cnd, eds. G. Boiteu, R. Singh, nd R. Prry, Fredericton, New Brunswick: Agriculture nd Agri-Food Cnd. 4.6 LE GÉNIE DES BIOSYSTÈMES AU CANADA DE LADURANTAYE ET AL.

7 Mot-Snchez, D., R. Hollingworth, E. Grfius nd D. Moyer Resistnce nd cross-resistnce to neonicotinoid insecticides nd spinosd in the Colordo potto beetle, Leptinotrs decemlinet (Sy) (Coleopter: Chrysomelide). Pest Mngement Science 62: Poprwski, T.J., R.I. Crruthers, J. Speese III, D.C. Vcek nd L.E. Wendel Erly-seson pplictions of the fungus Beuveri bssin nd introduction of the hemiptern predtor Perillus biocultus for control of colordo potto beetle. Biologicl Control 10: Rdcliffe, E.B., D.W. Rgsdle nd K.L. Flnders Mngement of phids nd lefhoppers. In Potto helth mngement, ed. Rndll C. Rowe, St. Pul, MN: APS Press. Sint-Cyr, J.F. nd C. Cloutier Prey preference by the stinkbug Perillus biocultus, predtor of the Colordo potto beetle. Biologicl Control 7: SAS Institute, Inc SAS user s guide: Sttistics. Ver Cry, NC: SAS Institute, Inc. Steel, R.G.D. nd J.H. Torrie Principles nd procedure of sttistics: A biometricl pproch, 2nd ed. New York, NY: McGrw-Hill, Inc. Whlon, M.E., D.L. Miller, R.M. Hollingworth, E.J. Grphius nd J.R. Miller Selection of Colordo potto beetle (Coleopter: Chrysolelide) strin resistnt to Bcillus thuringiensis. Journl of Economic Entomology 86: