In Florida resistance 7 90 Florida, Gainesville, FL 32611, USA. level, greater than 20-fold ltural and Veterinary Entomology, 2009 Society of Chemical Industry 90 c a Past research on New York dairies documented 4,6 t 2009 Published online in Wiley Interscience: 10 November 2009 a Musca domestica Correspondence to: Phillippartment, E Kaufman, PO Box Entomology 110620,E-mail: and pkaufman@ufl.edu University of Nematology De- Entomology and Nematology Department, UniversityFL, USA of Florida, Gainesville, USDA-ARS, Center forGainesville, FL, USA Medical, Agricu Here, the results of the first statewide survey of housefly Previous insecticide resistance research has included Florida Florida. Imidacloprid resistance is emerging, and tolerance aluated for resistance to four insecticides (beta-cyfluthrin, ∗ a b atively underutilized insecticide nithiazine had the lowest insecticide resistancewas in conducted with Florida field-collectedmeasuring populations are the susceptibility of levels to houseflies reported. commonly used by insecticides. The This aim was research toto survey allow for the the levels development of ofprevention a resistance program proactive in for insecticide resistance the Florida newand dairies active nithiazine, ingredients and imidacloprid toefforts. provide baselines for future monitoring dairy operations, the open architecture and managementlend systems themselves to even more housefly dispersalmost opportunities, animals as are housed outdoors. housefly strains, but thelimited in examination scope. of these strains has been that resistance patterns were similar across the state. Rajinder S Mann, a L., continues to be a major pest of confined livestock operations. Houseflies have resistance was observed in one southern Florida fly strain. Farm insecticide use and its 90 (Wellmark International, and Michael E Scharf  Sonia C Nunez, b (Bayer, Shawnee Mission, KS) ∗  Two insecticides have recently a L., continues to be a major pest Musca domestica 1–3 : 290–294 www.soci.org 66 Musca domestica 2010; Insecta; resistance; imidacloprid; nithiazine; fly bait; pyrethroid; 4,5

2009 Society of Chemical Industry Pesticide use on Florida dairies continues to rely on premise c resistance was found in two of the fly strains for permethrin and one fly strain for imidacloprid. Beta-cyfluthrin LC applications targeting adultapplications houseflies; are however, considerable especially made to with theon permethrin milking pastures or herd, againstof open as the lots. horn animals housefly The flies, baits are emergence QuickBayt and often rapid housed adoption been formulated as baitsnithiazine. for Studies housefly have control, shown imidaclopridto both and be of effective these against activesigns field ingredients populations of of resistance houseflies,observed. development but with early imidacloprid have been Pest Manag Sci 1INTRODUCTION The housefly, in livestock systems,pathogen particularly transmission, dairies, irritationdispersal owing to to humans to and its off-farmbe animals resistant role areas. and to in Housefliespermethrin most insecticides have and used been cyfluthrin. against shown them, including to BACKGROUND: The housefly, Abstract collected from Florida dairies Phillip E Kaufman, Christopher J Geden resistance in houseflies (Diptera: Muscidae) Nicotinoid and pyrethroid insecticide developedresistancetomostchemicalclasses,andnewchemistriesforuseinanimalagricultureareincreasinglyslowtoemerge.Five adult housefly strainspermethrin, from imidacloprid and four nithiazine). Florida dairy farms were ev RESULTS: Significant levels ofresistance was tolerance apparent were (as found deduced in from most comparison field with strains prior to published results). all At insecticides, the and LC in some cases substantial (www.interscience.wiley.com) DOI 10.1002/ps.1872 Research Article Received: 15 June 2009 Revised: 10 August 2009 Accepted: 10 Augus Schaumburg, IL) in the past 10 years provided dairyeffectiveoptionstocombatadulthouseflies.Theactiveingredients producers with in these two products,provide imidacloprid and a nithiazine quick respectively, producer. knockdown, However, within a which few years, reports iswere of received reduced visually from efficacy producers and appealing extension service to personnel. a ratios exceeded tenfoldresistance resistance ratios; however, fourfold in LC three fly strains. The rel and QuikStrike Fly Abatement Strip impact on resistance selection in Florida housefly populations are discussed. CONCLUSION: Housefly resistance to pyrethroidswas is observed widespread to in both imidacloprid and nithiazine. If these insecticides are to retain efficacy, producer use must be restrained. Keywords:

290 291 11 to 10 )that 7). As 2 . 12 22 values, resistance 90 = 90 90 and LC 50 as adapted to personal 8 using Abbott’s transformation 9 www.interscience.wiley.com/journal/ps C with a 12 : 12 h light : dark photoperiod. Flies ◦ 3) and Lafayette county strains (RR . 21 = 90 Significant levels of beta-cyfluthrin resistance were found in The insecticide-susceptible FS strain was used to generate a The two university dairy strains collected 22 months apart from Between nine and 11 concentrations were used to generate Imidacloprid and nithiazine do not penetrate the insect all housefly strains examined, with three of the LC reported earlier, theexposure Lafayette to permethrin. county fly strain had extensive complete concentration–response line for allinsecticide. fly Bioassay strains data with from each three replications wereanalyzed pooled and by standard probit analysis, remained in residual contact bioassay jars for 48was h assessed. before During mortality this holding period, fliesa were 20% provided sugar with solution onwere a cotton exposed wick. to Flies innithiazine-treated imidacloprid-treated feeding sugar bioassays sugar cubes cubes forimmediately for following 24 h; exposure. 96 h In mortality feedingprovided or was with bioassays, water assessed flies on a were cotton wick.considered In dead both if bioassays, they flies were were ataxic. computer use by Raymond and all hypotheses were tested by the likelihood ratio test. 3The RESULTS AND highest DISCUSSION levelspermethrin of (Table 1). insecticide Allsignificantly resistance field-collected more were tolerant strainsFS or examined found strain, resistant depending were with on to thethe strain–insecticide permethrin greatest than combination, resistance with the ratios07 (RR) (RR observed in flies from the UF the same facility (UF 05–06 and UF 07) demonstrated a dramatic ratios at 10.0 orstrain demonstrated greater the highest level (Table of 2). beta-cyfluthrin(14.4), resistance Adult whereas resistant houseflies ratios with from UF 05–06at UF the strain 07 flies same collected farm 2the years FS strain, earlier but were had considerably significantly lowerstrain. different LC values from than the UF 07 concentration–response curves. For all insecticidestrations, at a minimum all of concen- 240 houseflies wereconducted tested. at Bioassays were 26 integument well andtherefore, a feeding assay are was used to commerciallyFemale flies evaluate (20) these were insecticides. placed formulated in plastic 500 as mLprovided containers and with were baits; three 3.5Savannah g LP, sugar Sugar cubes Land,of (Dixie TX) Crystals, either each Imperial- imidacloprid containingImidacloprid or a was serial serially nithiazine dilution dilutedserially or in diluted in a acetone, ethanol. and The solvent-only serially nithiazineonly diluted control. was control solution or (0.5 solvent- mL)solvent was was applied to allowedcontainers each to 1 h sugar evaporate. after cube, treatment. Flies and were the introduced into had been treated with technical-gradein insecticide acetone serially to diluted deliver a concentration–mortalityand 95%. range between 0 correct for control mortality.strain Resistance standard, ratios, were based determined on using the LC FS 2.2 Laboratory bioassays Permethrin and beta-cyfluthrina toxicities were residual examined contactnithiazine using were method, examined using while acontact feeding imidacloprid method, assay. 20 For and adult the residual extracted placed female inside houseflies a 60 (3–5 mL glass days jar (internal old) surface were area 67.8 cm 2009 Society of Chemical Industry c 10 by volume). The + ter, PA), permethrin (99.2%, methanol (90 C. ◦ + A laboratory strain, Florida susceptible 3 : 290–294 66 2010; 32 : 68; Chem Service, West Chester, PA) and imidacloprid The Alachua county farm was the University of Florida’s dairy Three technical-grade insecticides were tested: beta-cyfluthrin Nithiazine was extracted from the bait strip formulation using Nicotinoid and pyrethroid housefly resistance www.soci.org entire process and subsequent storage was conducted into darkness prevent nithiazine breakdown. Ethanol extractsamber bottles were and stored held in at 9 (FS), of insecticide-susceptible houseflieslaboratory served as strain the standard withThis which strain all wasunchallenged colonized field since its in strains collection. the were late compared. 1960s andcalf has unit. Two remained fly strainsstrain were evaluated from (UF this farm, 05–06)January a merged 2006) from and a two secondInsecticide strain collections use (UF 07) (December at collected this 2005 inpour-ons applied late farm and to 2007. consisted calves monthly, ofadjacent permethrin permethrin-containing pour-ons paddocked on heifers the every(QuikStrike 2 weeks Fly and Abatement(April–December). nithiazine Strip) baits Houseflies duringcounty were the farm collected in housefly on October(non-lactating season animals) and 2007. the permethrin as This a Gilchrist pour-on, farmtags(non-lactating)overanextendedtimeframeandimidacloprid- diazinon ear had used coumaphos containing QuickBayt Fly Bait intermittently2004. at the The calf Lafayette area since countycollections in fly October 2007. This colony farm had was heavy useand of imidacloprid. established permethrin Permethrin was from applied in fly three waysear – tags through to cattle, asstructure a application daily – spray during to the cattle flyapplied as season. and needed QuickBayt as during Fly non-rain a times Bait twice-weekly outside is allbuildings. cattle-holding The Okeechobee countyMarch fly 2008. This strain farm was had previouslytags established used (non-lactating in organophosphate cattle) ear on pastured cattle,as pyrethroids a applied fog in facilitiesareas. and QuickBayt Fly Bait as needed in the barn (99.5%; Chem Service,cis : West trans Ches (99.5%; Chem Service, Westticide Chester, PA). was One examined: formulated nithiazineStrip). insec- (Quikstrike 1.0% Fly Abatement the following procedure. Thecontaining formulation, the a yellowpaper nithiazine, bait support matrix was structure.and scraped The placed from in resultant a100% mixture the 50 ethanol mL was bait was screw-topplaced weighed glass added. strip on vial a The rotisserie to test shakerIA) which (Barnstead tube International, and 50 mL Dubuque, was rolled of transferred covered to for in a 24 foil, cleanas h. amber the After container stock rotation, forwas solution. storage calculated The the by and concentration using supernatant served percentage the of of initial was the the matrix formulation stock weight thatbaitstripandtherecoveredvolumeofethanol–nithiazinesolution. and solution had nithiazine been removed fromNithiazine the recovery wasusing verified Whatman by LHPKDF thin-layersystem plates chromatography of dichloromethane (Maidstone, UK) and a solvent Pest Manag Sci 2.1 Insects, farmsAdult and chemicals houseflies were collectedbarns by and sweep net around from calfGilchrist, within Lafayette areas and dairy Okeechobee on counties. Laboratory four colonies of Florida each dairies strain were in establishedbe Alachua, from free field of isolates determined pathogens to as and previously ectoparasites. described. Houseflies were reared 2 MATERIALS AND METHODS . and et al 1 − 1.8 (0.1) 1.9 (0.1) 2.0 (0.1) 2.2 (0.1) 1.9 (0.1) 2.0 (0.1) 1.8 (0.1) 1.9 (0.1) 2.1 (0.1) 1.8 (0.1) : 290–294 Slope (SE) Slope (SE) 66 gmL µ The houseflies 13 2010; sugar and an RR of ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ b,c b,c 1 study. The extended 90 90 − 2.8 5.3 3.6 9.9 4 11.9 14.4 10.0 21.3 10.8 22.7 RR RR value of 94 gg µ 50 Pest Manag Sci ∗ ∗ ∗ ∗ ∗ a,c a,c ∗ ∗ ∗ ∗ ∗ 50 50 value of 60 50 and nithiazine in the field (QuikStrike strip) 4 identified excellent linkage between laboratory 7 It was not possible to collect flies at either of these . 4 ) (95% CI) RR ) (95% CI) RR 2 2 et al − − gcm µ ( (ng cm Two previous studies measured the susceptibility of imidaclo- It is evident from the present results that houseflies in 90 90 prid in the laboratory studies and field efficacy; in particular, significantwere found resistance to ratios be associated with field controlstudies failures. While are these labor intensive,measure they of resistance appear potential. to provide an excellent Florida have acquired tolerance,to insecticides and used against in them. However, some fieldbe efficacy present. cases may still Here, resistance, tolerance wasincrease categorized in as the a resistance non-significant ratio,categorized while as resistant populations having were Kaufman significant resistance ratios. Previously, the QuikStrike Fly Abatement Strip.preciable However, susceptibility there differences were between no farmsno use ap- that of reported nithiazine. It appears thatinsecticide nithiazine against is houseflies still in an Florida. efficacious feeding in thevalues present and limit study the observed would magnitudeNevertheless, be of the tolerance/resistance. resistance expected ratios to were quite lower similar, suggesting LC dairies, as neither werein the in present operation study in tocounty those 2007. dairy, mentioned with The above an was closest LC the dairy Gilchrist collected in 2004 fromsusceptible to one imidacloprid, with of an LC these dairies were found to be on two Florida dairiesGilchrist that county were dairy used approximately in 15 the km present from study. the an RR of 3.1. 3.3. However, in the present96 assay, h, flies as were opposed allowed to to feed 72 for h in the Kaufman 90 www.soci.org PE Kaufman 2009 Society of Chemical Industry 15.72)30.28) 66.76 (57.72–78.69) 148.80 (128.55–175.45) 3.7 7.1 0.14) 0.33 (0.30–0.37) – – 3.3 (0.2) 4.29) 12.54 (10.66–15.31) – – 2.5 (0.2) ) (95% CI) LC ) (95% CI) LC c 2 2 Florida susceptible). Florida susceptible). Florida susceptible). Florida susceptible). − − 90 90 50 50 ousefly adults from dairies in Florida gcm (Table 4). Also, inter- µ ( (ng cm 90 50 50 LC LC of 23.7. Resistance ratios from 90 resistant strain/LC resistant strain/LC resistant strain/LC resistant strain/LC 90 90 50 50 n n 21602160 0.23 (0.21–0.25) 1.54 (1.41–1.68) 1.17 (1.02–1.37) 6.98 (6.14–8.06) 1.7 11.5 19201920 8.17 (7.34–9.08) 35.12 (32.02–38.52) 180.13 (155.62–212.49) 34.60 (29.55–41.60) 9.1 2.1 than the susceptible laboratory strain. It (i.e. LC (i.e. LC (i.e. LC (i.e. LC 90 90 50 50 50 , and four of the five strains demonstrated 50 Toxicity of beta-cyfluthrin on glass to h Toxicity of permethrin on glass to housefly adults from dairies in Florida d d d d Significantly different from 1.0, based on non-overlap of 95% CI. Significantly different from 1.0, based on non-overlap of 95% CI. Resistance ratio at LC Resistance ratio at LC University of Florida dairy, Alachua county, FL. University of Florida dairy, Alachua county, FL. Resistance ratio at LC Resistance ratio at LC ∗ ∗ All Florida housefly strains examined were significantly resistant Three of the five housefly stains demonstrated significant dif- b c d UF 05-06 a Florida susceptible 1700 3.86 (3.48– Table 2. c d a b Strain Florida susceptible 2400 0.13 (0.12– Table 1. Strain UF 05-06 UF 07 GilchristLafayetteOkeechobee 2400 1920 2160 0.82 (0.75–0.89) 0.72 1.89 (0.64–0.80) (1.73–2.06)UF 07 3.53 (3.12–4.06)Gilchrist 3.25 7.43 (2.78–3.90) (6.58–8.53)LafayetteOkeechobee 6.1 14.1 5.4 2400 1920 1920 14.22 (12.84– 27.57 29.92 (25.08– (27.47–32.57) 124.89 (110.05–143.93) 7.7 significant tolerance/resistance at the LC estingly, the Gilchrest countysusceptible dairy at flies the were LC significantly more is not surprising thatthan nithiazine the tolerance tolerance levels levels of are thebecause much other three of lower insecticides the examined method ofrelatively application lower for use this by insecticide producers.Strike Fly and Nithiazine Abatement Strip, its is which is sold a prefabricated as devicethe wherein the chemical Quik- is appliedhousing. to Because a the chemical strip breaks that downmust readily is be in placed used sunlight, it indoors within orcontrast, a in the plastic sunlight-protected imidacloprid outdoor product areas.that (QuickBayt) In is is scattered a in granular areasby that bait producers flies frequent much and more has frequently.the been To University utilized the of authors’ Florida dairy knowledge, was the only facility regularly to use www.interscience.wiley.com/journal/ps increase in permethrin andvalues beta-cyfluthrin rising from tolerance, 1.17 with to180 LC 6.98 for beta-cyfluthrin. for Such permethrin a and dramaticprior rise from selection in 34.60 tolerance with to suggests pyrethroids or2007 perhaps shortly a after collection pyrethroid exposure. of flies in to imidacloprid; however, some resistance ratioslow remain relatively (Table 3). Thelargest Lafayette resistance level, county with an dairy RR houseflies carried the the remaining dairies were considerably lower. All were significant, however, suggesting that thereimidacloprid is efficacy with a continued selection. strong potential for loss of ferences in nithiazine tolerance/resistance asFS compared strain with the at the LC

292 293 3,7 2.2 (0.1) 1.7 (0.1) 1.7 (0.1) 1.6 (0.1) 1.9 (0.1) 2.2 (0.1) 2.2 (0.1) 2.1 (0.1) 2.0 (0.1) Slope (SE) Slope (SE) and New York ∗ ∗ ∗ ∗ ∗ 5 b,c b,c ∗ ∗ ∗ ∗ 90 90 2.2 6.8 5.3 3.1 4.1 2.4 0.83.9 2.6 (0.1) 23.7 RR RR ∗ ∗ ∗ ∗ ∗ a,c a,c ∗ ∗ ∗ ∗ 50 50 3,7 www.interscience.wiley.com/journal/ps In these studies, insecticide application practices 3 ) (95% CI) RR ) (95% CI) RR 2 2 − − gg gg µ µ ( ( Although resistance to insecticide baits has been reported in 90 90 many insect species, few reports ofInsecticide resistance exist bait for applications houseflies. drivers have of been resistance consideredexhibited in low-impact houseflies by owingfood houseflies to substrates. the and great Recent the mobility work wide in range California of acceptable Heavy usage of insecticidespopulation by towards greater a resistance, producer especiallyof would in susceptible, likely the resistance-diluting absence drive populationsTherefore,theauthorssuggestthatthesituationinFloridaissimilar a on nearby farms. to the housefly resistance patternsoperations. observed in New York poultry ACKNOWLEDGEMENTS The authors thankassistance J and the Pitzer, Floridastudy. L dairy This farmers Wood who research and cooperated wasMilk in R supported Check-Off this grants by Hammel program theFlorida for and Southeast Agricultural in their Milk, Experiment part Inc. Station byproject Federal the FLA-ENY-04598 University Formula (Cooperative of Funds, and State Extension Service, Research, US Department Education of Agriculture). has documented thatmethomyl. houseflies The have present developed resultssuggest resistance with that imidacloprid to baits and containing nithiazine resistance development these when used toxicants heavily. are vulnerable to in enclosed poultrypesticide operations resistance were expression thanclustered more in dairies directly the in related open, thatlittle to to and state do to where with more resistancebetween producer the expression open applications farms). had (owing to fly movement 90% > 2009 Society of Chemical Industry ), suggesting 0.49) 1.04 (0.93–1.19) – – 3.6 (0.2) 2 c ) (95% CI) LC ) (95% CI) LC Florida susceptible). Florida susceptible). Florida susceptible). Florida susceptible). − 2 2 − − 90 90 50 50 gg gg documented µ µ 7 ( ( . 3ngcm 50 50 . 8 et al LC LC = 99 resistant strain/LC resistant strain/LC resistant strain/LC resistant strain/LC 90 90 50 50 n n 19201920 0.49 (0.44–0.55) 0.66 (0.59–0.73) 1.87 (1.58–2.29) 2.53 (2.15–3.07) 1.1 1.4 1.8 17602160 38 (34–43) 77 (68–87) 143 (122–173) 446 (369–555) 2.1 4.3 level (LC (i.e. LC (i.e. LC (i.e. LC (i.e. LC 99 90 90 50 50 : 290–294 LC 66 × reported sevenfold permethrin resistance in 14 2010; . Toxicity of nithiazine fed in a sugar bait to housefly adults from dairies in Florida Toxicity of imidacloprid fed in a sugar bait to housefly adults from dairies in Florida d d et al d d Significantly different from 1.0, based on non-overlap of 95% CI. Significantly different from 1.0, based on non-overlap of 95% CI. Resistance ratio at LC University of Florida dairy, Alachua county, FL. University of Florida dairy, Alachua county, FL. Resistance ratio at LC Resistance ratio at LC Resistance ratio at LC ∗ ∗ Housefly exposure to pyrethroids may be different under Florida Imidacloprid and, to a lesser extent, nithiazine appear to be The pyrethroid resistance levels observed here are considerable UF 07 GilchristLafayetteOkeechobee 1920 1920 2160 60 (50–70) 231 (207–258) 43 (37–50)UF 07 Gilchrist 1550 (1276–1941) 346 (273–462) 202 (159–274)Okeechobee 12.8 1920 3.3 1920 2.4 0.27 (0.25–0.31) 0.99 (0.87–1.13) 0.85 (0.73–1.00) 4.31 (3.51–5.52) 0.6 2.1 UF 05-06 b c d a Florida susceptible 1920 0.46 (0.44– Table 4. c d Strain a b Florida susceptibleUF 05-06 1920 18 (15.5–21) 65 (52–89) – – 2.3 (0.2) Table 3. Strain Lafayette 1920 0.98 (0.89–1.08) 4.04 (3.44–4.85) 2.1 Nicotinoid and pyrethroid housefly resistance www.soci.org houseflies from Nebraska, and Kaufman an RR approaching 3.0. The presenthousefly results document populations that have Florida exceeded thesome New cases York levels, the and Nebraska in cross-resistant levels, to the and newer are pyrethroids. becoming increasingly animal husbandry conditions. In otherit areas of is the common United for States with producers a to pyrethroid treat residualapplications walls to spray. and structures In other are Florida,open structures much architecture although of less buildings, pesticide common the use owingfrequent. of Moreover, pour-on to because many formulations cattle the is are pastured orpaddocks placed during in the day, houseflies are regularly observed resting on animals or feeding on theiris secretions increasingly while common out-of-doors. This under dryoften conditions serve where as the a animals sourcehouseflies for to water. pyrethroids To applied this to extent,facilitated animals by the as these exposure regional pour-ons of conditions. may be losing their effectiveness,of and imidacloprid the warrants continued concern.Florida may That widespread be partially resistance use explainedand is by the relative greater longer dispersal in housefly of season confined dairy operations in the state. Pest Manag Sci that imidacloprid resistance selection ofFlorida houseflies had in not this changed appreciably part between of 2004 and 2007. and reflect aMarcon higher level than had previously been reported. survival of Newhouseflies to York the 3 dairy-farm-collected, cyfluthrin-exposed . .CRC et al :244–250 : 290–294 30 66 2010; JVectorEcol eedlots to selected insecticides. :257–261 (1977). 23 Pest Manag Sci ood ratio tests of dose–mortality Cah ORSTROM, ser Ent Med Parasitol Pesticide Bioassays with Arthropods , 3rd edition. Cambridge University Press, :1016–1020 (2003). :265–267 (1925). L. (Diptera: Muscidae). 96 18 Bull Entomol Soc Am Probit Analysis :117–121 (1985). Musca domestica Press, Boca Raton, FL (1992). in insecticide research:regression. likelih (2005). Resistance statusSoutheastern Nebraska beef cattle of f J Econ house Entomol flies (Diptera: Muscidae) from J Econ Entomol London, UK (1971). probit pour micro-ordinateur. 23 8 Finney DJ, 9 Raymond M, Presentation d’un programme Basic d’analyse log- 13 Geden CJ, Methods for monitoring outdoor populations of house flies, 11 Robertson JL and Preisler HK, 12 Savin NE, Robertson JL and Russel RM, A critical evaluation of bioassay 14 Marcon P, Thomas GD, Siegfried BD, Campbell JB and Skoda SR, 10 Abbott WS, A method of computing the effectiveness of an insecticide. JEcon :53–64 6 www.soci.org PE Kaufman :514–521 57 2009 Society of Chemical Industry Pest Manag Sci c :105–110 (2006). 23 JAgricEntomol Pest Manag Sci :195–200 (2006). L.) in the United States to )-9-tricosene and efficacy of 23 , House fly (Diptera: Muscidae) Z Southern California dairy. , ed. by Georghiou GP and Saito T. J Agric Urban Entomol Musca domestica J Agric Urban Entomol :1489–1495 (2007). 100 , Susceptibility of field collected house flies to spinosad before Pest Resistance to Pesticides :147–153 (2000). in Plenum Press, New York, NY, pp. 1–46 (1983). insecticides at dairies across New York. of house flies ( (1989). in house flies56 from caged-layer poultry facilities. imidacloprid. activity near baits containing ( in house flies from New York dairies. (2001). Entomol et al and after a season of use. commercial toxic fly baits on a 1 Georghiou GP and Mellon R, Pesticide resistance in time and space, 2 Scott JG, Roush RT and Rutz DA, Resistance of house flies to five 4 Kaufman PE, Gerry AC, Rutz DA and Scott JG, Monitoring susceptibility 3 ScottJG,AlefantisTG,KaufmanPEandRutzDA,Insecticideresistance 5 Butler SM, Gerry AC and Mullens BA 7 Kaufman PE, Scott JG and Rutz DA, Monitoring insecticide resistance 6 Deacutis JM, Leichter CA, Gerry AC, Rutz DA, Watson DW, Geden CJ, www.interscience.wiley.com/journal/ps REFERENCES

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