Efficacy of noviflumuron gel bait for control of the German cockroach, Blattella germanica (Dictyoptera: Blattellidae) laboratory studies

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1 Pest Mngement Science Pest Mng Sci 62: (2006) Efficcy of noviflumuron gel it for control of the Germn cockroch, Blttell germnic (Dictyopter: Blttellide) lortory studies Chnglu Wng nd Gry W Bennett Center for Urn nd Industril Pest Mngement, Deprtment of Entomology, Purdue University, West Lfyette, IN 47907, USA Astrct: The insecticidl ctivity of cockroch gel it contining chitin synthesis inhiitor, noviflumuron, ws evluted using lortory nd field strins of the Germn cockroch, Blttell germnic (L.). Noviflumuron gel it ( mg g 1 ) cused 90% nymphl mortlity to lortory nd field strins of B. germnic in choice tests fter 11 nd 19 dys of continuous exposure respectively. In 1 m 1 m iossy rens, lortory strin B. germnic popultion levels exposed to 5 mg g 1 noviflumuron it or 0.1 mg g 1 fipronil gel it were significntly lower thn untreted popultion levels fter 3weeks nd 1week of exposure respectively. Vrious noviflumuron it exposure periods (2, 4 nd 7 weeks) cused similr popultion reductions, with men of 99.3 (±0.3)% t 7 weeks. ipronil gel it cused 100% popultion reduction t 2 weeks post-exposure. The control popultion incresed 89.0% t 7 weeks. In simulted kitchen experiment with mixed stge lortory popultions, cockroch trp ctches decresed 96.8 (±2.0)% t 8 weeks in the 0.5 mg g 1 noviflumuron it tretment. The trp ctches in the control incresed (±493.7)% during the sme period. Trp ctch reduction y 0.1 mg g 1 fipronil gel it reched 100% t 4weeks. Noviflumuron it cused significntly lower nymph/totl rtios to B. germnic popultions in iossy rens from 2 weeks fter exposure, demonstrting its effectiveness s control gent for B. germnic with pttern of ctivity similr to tht expected from chitin synthesis inhiitor Society of Chemicl Industry Keywords: Blttell germnic; noviflumuron; fipronil; gel it; efficcy 1 INTRODUCTION The Germn cockroch, Blttell germnic (L.), continues to e mjor indoor pest in mny prts of the world despite the vilility of effective modern insecticides. A survey indicted tht 50% of lowincome residences in Gry, IN, USA were infested y B. germnic during (Wng C et l., unpulished). Cockroches not only contminte food, they lso cuse llergic rections. Cockroch llergens re some of the most prominent llergens in inner-city homes. 1,2 People cn ecome sensitised to proteins produced y cockroches. A recent study showed tht even low levels of exposure to cockroch llergens re risk fctor for cockroch sensitistion. 3 Exposure to cockroch llergens hs een reported to e mong the most importnt risk fctors in severe sthm symptoms nd mortlity for children living in inner cities. 4,5 The prevlence of B. germnic is prtly due to its reltively smll size, high level of fecundity nd shorter development time thn other cockroch pest species. 6 Besides its iologicl chrcteristics, B. germnic is lso notorious for its ility to develop physiologicl nd ehviourl resistnce to insecticides. 7,8 Over the yers, numerous chemicls nd formultions hve een developed to comt cockroch infesttions. These products were often effective for control of B. germnic t the eginning, ut filed fter n extended period of use owing to the development of resistnce nd/or were withdrwn owing to sfety concerns. igh levels of B. germnic resistnce to ll mjor neurotoxins hve een reported. 9 Recently, some B. germnic popultions were reported to hve developed high levels of resistnce to gel its (Mxforce, Mxforce C, Avert, Pre-Empt) fter repeted pplictions. This clls for more selective use of ville tools nd the development of new chemistries nd formultions to slow down or circumvent the development of cockroch resistnce. New chemicls, especilly those in novel ctegories tht exhiit different insecticidl mechnisms, re prticulrly eneficil in insecticide resistnce mngement. Noviflumuron is n insect growth regultor (IGR) in the clss of enzoylphenyl ures. 13 This compound inhiits insect chitin synthesis nd therefore disrupts the moulting of nymphs nd emryo development. Cockroch nymphs ingesting enough noviflumuron will die efore or during the moulting process. Adult cockroches exposed to noviflumuron Correspondence to: Chnglu Wng, Deprtment of Entomology, Purdue University, 901 West Stte Street, West Lfyette, IN 47907, USA E-mil: chngluw@purdue.edu Contrct/grnt sponsor: Dow AgroSciences LLC (Received 3 une 2005; revised version received 7 Septemer 2005; ccepted 10 Septemer 2005) Pulished online 20 Mrch 2006; Society of Chemicl Industry. Pest Mng Sci X/2006/$30.00

2 Efficcy of noviflumuron gel it ginst Blttell germnic fil to produce vile eggs, hence their reproductive potentil is reduced. 14 Previous studies indicted tht noviflumuron formulted s suspension concentrte, dust or gel it cn effectively suppress B. germnic popultions under lortory nd field conditions. These promising results prompted us to investigte noviflumuron s insecticidl ctivity. In this study we report results on (1) the concentrtion mortlity response of B. germnic to noviflumuron gel it under lortory conditions, (2) the differentil response of lortory nd field strins of B. germnic to noviflumuron gel it, (3) the effect of exposure period on control efficcy nd (4) the comprtive efficcy of noviflumuron gel it nd commercil gel it for control of B. germnic popultions. 2 MATERIALS AND METODS 2.1 Insects nd gel its Two B. germnic strins were tested. The wx strin is stndrd susceptile strin mintined in the lortory for over 30 yers. It ws originlly collected efore the widespred use of synthetic orgnic insecticides. The Muncie strin ws collected from eight prtments in Muncie, IN, USA, 1.5 months prior to the experiment. These prtments hd received vriety of pyrethroid spry, it nd oric cid dust pplictions y residents nd mngement stff over period of 5 yers efore collection. Both strins were rered in the lortory on rln Tekld rodent diet (rln Tekld, Mdison, WI, USA). Cockroches were mintined in 40.5cm 28.0cm 14.5cmplstic oxes in wlk-in environmentl chmers t 26 C, 60% reltive humidity (R) nd 12/12 h light/drk photoperiod. The noviflumuron gel it ws provided y Dow AgroSciences LLC (Indinpolis, IN, USA). A fipronil cockroch gel it (0.1 mg AI g 1, Mxforce C, Byer Environmentl Science, Rleigh, NC, USA) ws purchsed from commercil distriutor. 2.2 Concentrtion mortlity response of lortory nd field Blttell germnic to noviflumuron gel it Twenty wx or Muncie strin smll nymphs (2nd 3rd instr) were trnsferred to individul plstic oxes (18.7cm 13.3cm 9.5 cm) fter rief nesthetistion y cron dioxide. Ech ox contined wter vil nd 10 cm 10 cm crdord tent s hrourge. After 1 dy of cclimtistion, food (3 cm 3 cm of white red nd one piece of rodent chow) nd 0.8 g of noviflumuron gel it were dded to the oxes. The it ws dispensed into smll plstic weigh continer. Noviflumuron concentrtions in the its were 0, 0.01, 0.1, 1 nd 5 mg g 1. Ech concentrtion (tretment) ws replicted three times for ech strin. The cockroches hd ccess to the tretment continuously during the experiment. Ded cockroches were counted nd removed every 1 3 dys until dy Comprtive efficcy of noviflumuron nd fipronil cockroch gel its ginst Blttell germnic popultions in 1 m 1 m rens Biossy rens (1 m 1 m) were constructed from Plexigls sheets (wlls) nd 2 cm thick prticle ord (floor) with white pinted surfce. A thin lyer of petroleum jelly + minerl oil (1 + 2 y volume) ws pplied to the ren wlls 5 10 cm ove the ren floor to prevent cockroches from escping. Ech ren contined two hrourge units t the centre, two food plcements (one piece of rodent chow, penut oil soked in filter pper, nd grpe jelly) nd two wter vils locted t opposite corners. Ech hrourge unit consisted of eight plywood pnels (9 cm 10 cm) seprted y 5 mm spcers. ive hundred wx strin cockroches were relesed into ech ren in the following ge structure: 250 smll nymphs (2nd 3rd instr), 125 lrge nymphs (4th 5th instr), 65 dult mles nd 60 non-grvid femles. They were llowed to cclimtise for 2 dys. Ded nd wek cockroches were replced with helthy cockroches immeditely efore the introduction of its. ive tretments were included: untreted control, 0.1mgg 1 fipronil cockroch gel it nd 5 mg g 1 noviflumuron gel it with exposure periods of 2, 4 nd 7 weeks. The inclusion of vrious exposure periods llowed us to exmine whether the removl of it fter exposure for 2 nd 4 weeks would ffect the result. The experimentl units were oserved for 7 weeks fter tretment. Ech tretment ws replicted three times. The it ws provided in 1.7 ml centrifuge vils ech contining 1 g of it. our vils were plced in ech ren, one in ech corner. Extr vils of it were left in petri dish in the sme room for ging. When it vil ecme empty, it ws replced with vil contining sme-ged it so tht cockroches hd continuous ccess to the it. The numers of live cockroches were counted weekly until 7 weeks. The hrourges were disssemled during ech counting to otin ccurte numers. They were recorded s the following: mle dult, femle dult, lrge nymph nd smll nymph. Ded cockroches in the rens were removed fter ech counting. The experimentl units were mintined in room t 27 C, 38% R nd 12/12 h light/drk photoperiod. 2.4 Comprtive efficcy of noviflumuron nd fipronil cockroch gel its ginst Blttell germnic popultions in simulted kitchens This experiment ws designed to compre the effectiveness of noviflumuron it with tht of commercil it product for the control of B. germnic popultions in conditions similr to field situtions. The tretments were s follows: 0.1mgg 1 fipronil cockroch gel it (Mxforce Pest Mng Sci 62: (2006) 435

3 C Wng, GW Bennett loor cinet Wll cinet loor cinet W Box Entrnce Window W igure 1. A ird s eye view of the simulted kitchen. Shded ojects were locted inside the cinets (, food; W, wter;, hrourge;, jr trp for monitoring cockroch popultions efore nd fter tretment). C), 0.5mgg 1 noviflumuron gel it nd untreted control. Ech tretment ws rndomly ssigned to simulted kitchen. The kitchens were locted in the sement of the Whistler ll of Agriculturl Reserch uilding t Purdue University. The environmentl conditions were C, % R nd 12/12 h light/drk photoperiod. The kitchens (3.05 m 1.83 m 2.67 m) were mde of wood pnels. Their inner surfces were pinted white. The entrnce ws locted on the roof of the kitchen. Petroleum jelly + minerl oil (1 + 2 y volume) ws pplied to the perimeter of the entrnce to prevent cockroches from escping. Ech kitchen hd two cinets (150 cm 60 cm 85 cm) on the floor nd one cinet (75 cm 30 cm 15 cm) on the wll (ig. 1). Crdord rolls nd crdord ox were provided s hrourges. Two wter jrs (476 ml ech, with cotton wicks) nd six food plcements (ech with penut oil, grpe jelly nd rodent chow) were provided s wter nd food sources. wx cockroches were relesed 6 7 dys prior to it plcement. The ge structure (smll nymph/lrge nymph/dult mle/nongrvid femle/grvid femle) of replicte 1 ws 725:250:150:100:50. The ge structure of replictes 2 nd 3 ws 700:250:150:50:100. Ten y food jr trps (6.5 cm tll, 4.5 cm opening, 124 ml volume) were plced in ech kitchen for 24 h to otin cockroch counts. Ech jr contined oneninth of slice of white red soked with 3 ml of eer (Miller Lite, Miller Brewing Co., Milwukee, WI, USA). The upper inner surfce of the jrs hd thin lyer of petroleum jelly + minerl oil (1 + 2 y volume) to prevent escpe. Trpped cockroches were relesed ck into the kitchens fter counting. Immeditely fter the initil trpping, one 1.7 ml centrifuge vil contining 0.8 g of it ws plced t the sme loction of the jr trp. Two dditionl vils were plced eside the crdord ox on the floor. r trps were deployed for 24 h every 7 dys until 8 weeks. The weight of the it vils in ech kitchen ws mesured weekly. Consumption of it ws clculted using the formul given y Wng et l. 12 Empty vils were replced with vils contining sme-ged it. Cockroch food ws replenished every 2 3 weeks. Ded cockroches, cockroch skins nd oothece (full or empty) were removed from the kitchens every 4 7 dys. At the end of the 8 week period the remining numers of cockroches in ech kitchen were estimted y oth jr trps nd visul inspection. The kitchens (including the cinets) were clened with disposle cloths nd sopy wter. They were then used for the next replicte of the experiment. Ech tretment ws replicted three times over time. or ech replicte the kitchens were rndomly ssigned to the three tretments. 2.5 Sttisticl nlysis The time mortlity response dt were nlysed y Proc Proit in SAS. 18 Times for 50% (LT 50 ) nd 90% (LT 90 ) mortlity were estimted for ech concentrtion nd strin comintion. Cockroch counts (log trnsformed) were nlysed y mixed models with repeted mesurements (Proc Mixed). Tretment mens were compred using isher s lest significnt difference (LSD). Nymphl rtios (nymph/totl) were clculted where the trp ctch ws 10. The noviflumuron tretments were comined s one tretment, ecuse some rens hd too few cockroches fter 4 weeks nd these tretments hd similr effects on the cockroches. The nymphl rtios from the control nd noviflumuron tretments were nlysed y mixed models with repeted mesurements (Proc Mixed). Bit consumption ws log trnsformed prior to nlysis of vrince (ANOVA). Rtios of full (with ded emryos) oothece to empty oothece collected in the kitchens were squre root trnsformed prior to ANOVA. 436 Pest Mng Sci 62: (2006)

4 Efficcy of noviflumuron gel it ginst Blttell germnic Tle 1. Efficcy of noviflumuron gel it ginst lortory (wx) nd field (Muncie) Germn cockroch smll nymphs (2nd 3rd instr) Model prmeters Lethl time (dys) Model fit Strin Rte (%) n Intercept (±SE) Slope (±SE) LT 50 (95% L) LT 90 (95% L) χ 2 D P wx (±0.6) 6.8 (±0.6) 5.7 ( ) 9.5 ( ) (±0.3) 2.5 (±0.3) 3.4 ( ) 11.1 ( ) (±0.6) 6.4 (±0.6) 6.6 ( ) 10.5 ( ) (±0.8) 6.1 (±0.6) 7.2 ( ) 10.7 ( ) Muncie (±0.8) 6.1 (±0.6) 11.0 ( ) 17.8 ( ) (±0.5) 5.7 (±0.4) 10.5 ( ) 17.4 ( ) (±0.5) 4.6 (±0.4) 9.5 ( ) 18.1 ( ) (±0.6) 6.6 (±0.5) 9.4 ( ) 14.6 ( ) Totl numer of trils with cockroches t ech oservtion. The intercept nd slope prmeters re for models in which the independent vrile is the nturl logrithm of the exposure time (dys). 3 RESULTS 3.1 Concentrtion mortlity response of lortory nd field Blttell germnic to noviflumuron gel its Noviflumuron it-induced mortlity of wx nd Muncie strin cockroches occurred 2 nd 7 dys fter exposure respectively. This ws independent of the noviflumuron concentrtion in the it. All concentrtions cused high level of mortlity ( 90%, corrected y Aott 19 ) to wx nd Muncie strins t 20 dys. The mortlity of the Muncie strin occurred much more slowly thn tht of the wx strin, s indicted y its much lrger LT 50 nd LT 90 vlues compred with the wx strin (Tle 1). 3.2 Comprtive efficcy of noviflumuron nd fipronil cockroch gel its ginst Blttell germnic popultions in 1 m 1 m rens The 5 mg g 1 noviflumuron gel it (4 nd 7 week exposure tretments) cused significntly lower popultion counts (P < 0.05, LSD) thn the untreted control t 3 7 weeks fter exposure (ig. 2). The 2 week exposure tretment cused significntly lower popultion counts thn the control t 4 7 weeks fter exposure. The three noviflumuron tretments resulted in similr popultion reductions t 7 weeks (P > 0.05, LSD). The men numer of surviving cockroches for the three noviflumuron tretments t 7 weeks ws 3.3 (±1.3). ipronil gel cused significntly lower popultion counts thn the control 1 week fter exposure (t = 5.1, degrees of freedom (D) = 64, P < 0.001). The men numer of cockroches in the fipronil tretment ws 6.3 (±2.7) fter 1 week of exposure. No live cockroches existed fter 2 weeks of exposure to fipronil. Compred with fipronil, the effect of noviflumuron on lortory strin B. germnic ws much slower. The untreted control popultion incresed 89.0% t 7 weeks s result of reproduction y the femles. The noviflumuron it tretments cused significntly lower cockroch nymphl rtios thn the control from 2 weeks (P < 0.05, LSD) (ig. 3). At 4 weeks the Survivl Control Noviflumuron-4wk ipronil Weeks fter Tretment Noviflumuron-2wk Noviflumuron-7wk igure 2. Effect of 5 mg g 1 noviflumuron gel it nd 0.1mgg 1 fipronil gel it on Germn cockroch (wx strin) popultions in 1m 1 m rens. ive hundred cockroches were exposed to noviflumuron it for 2, 4 nd 7 weeks nd fipronil it for 7 weeks. Nymph/Totl Rtio Weeks fter Tretment Control 5 mg g 1 Noviflumuron igure 3. Effect of 5 mg g 1 noviflumuron gel it on Germn cockroch (wx strin) popultion structure in 1 m 1 m rens. Brs with different letters indicte significnt differences (P < 0.05). emergence of lrge numers of smll nymphs cused n increse in nymphl rtios in some of the rens nd lrge vrince in the men nymphl rtio. After 4 weeks, nymphl rtios in the noviflumuron tretments remined significntly lower thn tht of the control. Pest Mng Sci 62: (2006) 437

5 C Wng, GW Bennett Men Trp Ctch (log(n+1)) Weeks fter Tretment Control 0.1 mg g 1 ipronil 0.5 mg g 1 Noviflumuron igure 4. Effect of 0.5mgg 1 noviflumuron gel it nd 0.1mgg 1 fipronil gel it on Germn cockroch (wx strin) popultions in simulted kitchens. 3.3 Comprtive efficcy of noviflumuron nd fipronil cockroch gel its ginst Blttell germnic popultions in simulted kitchens The 0.5mgg 1 noviflumuron gel it cused significntly (t α = 0.10) greter trp ctch reduction thn the control 4 weeks fter tretment (t = 2.01, D = 26, P = 0.055) (ig. 4). The men trp ctch reduction ws 82.6 (±7.5)% t4weeks. Visulinspection t 8 weeks fter tretment showed tht the men numer of live cockroches in the 0.5mgg 1 noviflumuron-treted kitchens ws 37 (±7). All the surviving cockroches were dults. ipronil gel cused significntly (t α = 0.10) greter trp ctch reduction thn the control 1 week fter tretment (t = 1.73, D = 26, P = 0.096). At 4 weeks, only one replicte in the fipronil tretment contined live cockroches. At 8 weeks the men trp ctch in the control incresed (±493.7)%. Visul inspection showed tht the remining numers of cockroches in the control rnged from 600 to No nymphs were found in the noviflumuron-treted kitchens 5 weeks fter tretment (sed on jr trp counts). The mjority of the remining dult grvid femles crried lck or deformed oothece. The men rtio of unhtched oothece to htched oothece collected from the noviflumuron-treted kitchens (0.66 (±0.27)) ws significntly higher thn tht from the control kitchens (0.10 (±0.02)) ( = 7.84, D = 1, 4, P = 0.049). Cockroches consumed significntly more noviflumuron it thn fipronil it ( = 6.73, D = 1, 2, P = 0.015). Men consumption of 0.5mgg 1 noviflumuron nd 0.1mgg 1 fipronil ws (±4.19) nd 0.50 (±0.19) g per kitchen respectively. 4 DISCUSSION Results from this study indicte tht noviflumuron gel it with 0.01 mg g 1 AI is highly effective ginst B. germnic nymphs. Both 0.5 nd 5 mg g 1 concentrtions cn provide effective control of B. germnic popultions. Noviflumuron gel it ws pltle to oth lortory nd field strins of B. germnic. Even when lterntive food resources were present, cockroches consumed enough ctive ingredient to e killed. The differentil time mortlity response of the lortory nd field strins to noviflumuron it might e due to differences in their diet history nd/or differing development speed. A chitin synthesis inhiitor only kills nymphs prior to or during moulting. ield strins generlly hve longer periods etween moults thn lortory strins. 20 Therefore nymphs of field strin will tke longer to die thn lortory strin nymphs. Diet history influences the feeding ehviour of B. germnic. Our preliminry studies showed tht cockroches rered on mixed diet (rodent diet, penut utter, fruit jelly) consumed much less gel it thn those rered on single diet (rodent diet) sed on 3 dy consumption dt. Mixed food resources provide more lnced nutrients to cockroches. The Muncie strin ws exposed to much more diverse food in the field thn the lortory strin. It hd lso een exposed to cockroch gel its which hd similr physicl chrcteristics nd proly similr ingredients to the noviflumuron gel it. This exposure history my hve cused slower consumption of noviflumuron it in the Muncie strin nd contriuted to its slower time mortlity response to the it. In the 1 m 1 m ren experiment, lrge numers of smll nymphs emerged t 4 weeks. Although noviflumuron it ws removed in two of the tretments (2 nd 4 week exposure tretments), similr levels of B. germnic popultion reduction were chieved t 7 weeks fter initil exposure. The dditionl mortlity fter removl of the it suggested tht secondry kill (mortlity through exposure to noviflumuron-killed cockroches nd/or cockroch feces) ws n importnt fctor in the mortlity of B. germnic. Secondry kill with cockroch its s result of coprophgy, necrophgy nd cnnilism in B. germnic hs een reported These studies demonstrted tht exposure to ded cockroches nd feces produced y it-treted cockroches could induce significnt mortlity to the cockroches tht were not exposed to the toxic it. Smith et l. 16 showed tht 100% nymphl mortlity occurred fter exposure to cockroch feces collected from noviflumuron it-treted cockroches t 28 dys. The secondry kill of noviflumuron it through coprophgy ws similr to tht of hydrmethylnon gel it (Mxforce Roch Bit Gel). The secondry kill effect of noviflumuron it through necrophgy nd cnnilism is not cler. urther studies on this suject re wrrnted for etter understnding of the insecticidl ctivity of this it mtrix. The lrge rtios of unhtched oothece to htched oothece collected in the noviflumurontreted kitchens suggest strong ovicidl effect of noviflumuron. This effect ws lso supported y 438 Pest Mng Sci 62: (2006)

6 Efficcy of noviflumuron gel it ginst Blttell germnic the existence of lrge numers of femles crrying drkened or deformed oothece. The ovicidl effect contriuted to noviflumuron s overll good popultion suppression in simulted kitchens. This property is especilly eneficil for long-term suppression of B. germnic, which hs short reproductive cycle reltive to other cockroch species. The smller difference in speed of control etween noviflumuron nd fipronil gel it in the kitchen experiment compred with the ren experiment ws proly due to the filure of the grvid femles to produce nymphs in the simulted kitchen experiment. The slower ctivity of noviflumuron ginst B. germnic popultions compred with conventionl insecticides is n inherent chrcteristic of IGRs. The inclusion of conventionl insecticide in the mngement progrmme my e helpful for immedite suppression of cockroch popultions. Routine ppliction of conventionl insecticides for cockroch mngement is declining s result of cockroch resistnce development nd environmentl concerns. The unique mode of ction of noviflumuron provides n dvntge over conventionl insecticides in long-term mngement of cockroch infesttions. It is lso less likely to induce cockroch resistnce. There hve een no reports of cockroch resistnce to IGR products, lthough they hve een on the mrket for mny yers. As people ecome more concerned with their indoor environments, insecticide exposure nd insecticide resistnce, this new chemicl hs the potentil to ecome n importnt ddition to the ville tools for B. germnic mngement. ACKNOWLEDGEMENTS This study ws supported finncilly y Dow AgroSciences LLC. We re grteful to Michelle Smith for helpful discussions nd her support in crrying out the experiments, Brin udt nd Megn Lnning for their technicl ssistnce, nd Grzegorz Buczkowski nd Edwrd King for criticl review of the mnuscript. This is journl rticle No of the Agriculturl Reserch Progrm of Purdue University, West Lfyette, IN, USA. REERENCES 1 Geler EL, Seltzer L nd Bouzoukis K, Sensitiztion nd exposure to indoor llergens s risk fctors for sthm mong ptients presenting to hospitls. Am Rev Respir Dis 147: (1993). 2 Rosenstreich DL, Eggleston P, Kttn M, Bker D, Slvin RG, Gergen P, et l., The role of cockroch llergy nd exposure to cockroch llergen in cusing moridity mong inner city children with sthm. New Engl Med 336: (1997). 3 Mtsui EC, Wood RA, Rnd C, Knchnrks S, Swrtz L, Curtin-Brosnn, et l., Cockroch llergen exposure nd sensitiztion in suurn middle-clss children with sthm. Allergy Clin Immunol 112:87 92 (2003). 4 Cll RS, Smith T, Morris E, Chpmn MD nd Pltts- Mills TAE, Risk fctors for sthm in inner city children. Peditr121: (1992). 5 ussk,adkinsonn,egglestonp,dwsonc,vnnttm nd milton RG, ouse dust mite nd cockroch exposure re strong risk fctors for positive llergy skin tests in the childhood sthm mngement progrm. Allergy Clin Immunol 107:48 54 (2001). 6 Bennett GW, Corrign RM nd Owens M, Trumn s Scientific Guide to Pest Mngement Opertions (6th edn). Advnstr Communictions, Clevelnd, O (2003). 7 Cochrn DG, Insecticide resistnce, in Understnding nd Controlling the Germn Cockroch,ed.yRustMK,OwensW nd Reierson DA. Oxford University Press, New York, NY, pp (1995). 8 Silvermn nd Ross M, Behviorl resistnce of fieldcollected Germn cockroches (Blttode: Blttellide) to its contining glucose. Environ Entomol 23: (1994). 9 Schrf M nd Bennett G, Cockroch resistnce IPM: common sense pproch. Pest Contr 63:38 41 (1995). 10 rison B, Krmer R nd Dorsch, Styin live. Pest Contr Technol 31:24 29, 83 (2003). 11 Morrison G, Brile nd Mcom TE, Roches tke the it gin. Pest Contr Technol 32:62, 64, 66 (2004). 12 Wng C, Schrf ME nd Bennett GW, Behviorl nd physiologicl resistnce of the Germn cockroch to gel its (Dictyopter: Blttellide). Econ Entomol 97: (2004). 13 Krr LL, Sheets, King E nd Dripps E, Lortory performnce nd phrmcokinetics of the enzoylphenylure noviflumuron in estern suterrnen termites (Isopter: Rhinotermitide). Econ Entomol 97: (2004). 14 King E, Ovicidl ctivity of noviflumuron when fed to dult Germn cockroches (Dictyopter: Blttellide). Econ Entomol 98: (2005). 15 Ameen A, Kkeh W, Wng C nd Bennett GW, Lortory nd field efficcy of noviflumuron formultions ginst the Germn cockroch, in Proceedings of 4th Interntionl Conference on Urn Pests, ed. y ones SC, Zhi nd Roinson W. Pochonts Press, Chrleston, SC, pp (2002). 16 Smith MS, Krr LL, King E, Kline WN, Srgi R, Sheets, et l., Noviflumuron ctivity in household nd structurl insect pests, in Proceedings of 4th Interntionl Conference on Urn Pests, ed. y ones SC, Zhi nd Roinson W. Pochonts Press, Chrleston, SC, pp (2002). 17 Ameen A, Wng C, Kkeh W, Bennett GW, King E, Krr LL, et l., Residul ctivity nd popultion effects of noviflumuron for Germn cockroch (Dictyopter: Blttellide) control. Econ Entomol 98: (2005). 18 SAS Institute, SAS/STAT User s Guide, Version 8.SAS Institute, Cry, NC (2000). 19 Aott WS, A method of computing the effectiveness of n insecticide. Econ Entomol 18: (1925). 20 Ross M nd Mullins DE, Biology, in Understnding nd Controlling the Germn Cockroch,ed.yRustMK,OwensW nd Reierson DA. Oxford University Press, New York, NY, pp (1995). 21 Ghlhoff r E, Miller D nd Koehler PG, Secondry kill of dult mle Germn cockroches (Dictyopter: Blttellide) vi cnnilism of nymphs fed toxic its. Econ Entomol 92: (1999). 22 Silvermn, Vitle GI nd Shps T, ydrmethylnon uptke y Blttell germnic (Orthopter: Blttellide) y coprophgy. Econ Entomol 84: (1991). 23 Kopnic r R nd Schl C, Coprophgy fcilittes horizontl trnsmission of it mong cockroches (Dictyopter: Blttellide). Environ Entomol 28: (1999). Pest Mng Sci 62: (2006) 439