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Palatability and Efficacy of Emamectin Benzoate Gel Baits on Four Pest Cockroach Species

Permanent Link: http://ufdc.ufl.edu/UFE0021336/00001

Material Information

Title: Palatability and Efficacy of Emamectin Benzoate Gel Baits on Four Pest Cockroach Species
Physical Description: 1 online resource (93 p.)
Language: english
Creator: Bayer, Barbara E
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: american, americana, averse, bait, blatta, blattella, brownbanded, cockroach, gel, german, germanica, longipalpa, oriental, orientalis, periplaneta, supella
Entomology and Nematology -- Dissertations, Academic -- UF
Genre: Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Four species of pest cockroaches, the German, Blattella germanica, the brownbanded, Supella longipalpa, Oriental, Blatta orientalis and American, Periplaneta americana, were fed gel baits containing emamectin benzoate to determine relative palatability and efficacy. Emamectin benzoate gel baits were formulated as either emamectin A or emamectin B at concentrations of 0.05%, 0.1%, or 0.2%. For all cockroaches tested, there was no significant difference in palatability or efficacy between emamectin A 0.1% or emamectin B at 0.05%, 0.1% or 0.2%, with the exception of percent mortality of American cockroaches; emamectin B 0.05%, which had the lowest percent mortality, was significantly different from emamectin A 0.1%. Two German cockroach strains, the Daytona bait averse strain and the Orlando normal susceptible strain, of German cockroach were fed a set of experimental gel baits, emamectin A and B at 500 ppm (0.05%) and 1000 ppm (0.1%) emamectin benzoate. There was no significant difference in palatability of baits between strains; both strains consumed similar percentages of gel bait and dog food. Percent mortality from consumption of emamectin gel baits was between 80% and 90% at 6 d. A second set of experimental emamectin gel baits formulated at 0.05%, 0.1%, or 0.2% emamectin benzoate were fed to the Daytona German cockroach stain, brownbanded cockroaches, Oriental cockroaches and American cockroaches in order to determine palatability and efficacy. The emamectin gel baits were palatable to all four species. Only brownbanded cockroaches consumed similar percentages of gel bait and dog food. The other three species preferred the emamectin gel baits over dog food, with 78% to 99.7% of total consumption being emamectin gel baits. All four species were highly susceptible to the emamectin gel baits with 85% to 99% mortality at 14 d. Percent mortality from emamectin gel baits was similar to Maxforce FC Select for the Daytona German cockroach strain and brownbanded cockroach. For the Oriental cockroach, percent mortality from emamectin gel baits, emamectin A 0.1% and emamectin B 0.1% and 0.2%, was similar to Maxforce FC Select at 14 d. For American cockroaches, there were no statistical differences between Maxforce FC Select and the emamectin gel baits, emamectin A 0.1% or emamectin B 0.2%, with 98.6% and 96.4%, respectively, at 14 d. All formulations and dosages of emamectin gel baits were palatable to all cockroach species tested. Additionally, when fed emamectin gel baits, high susceptibility, 85% to 99.5% mortality, was observed for all pest cockroaches tested at 14 d. Therefore, cockroach gel baits containing emamectin benzoate show excellent potential for controlling pest cockroaches.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Barbara E Bayer.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Koehler, Philip G.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2008-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021336:00001

Permanent Link: http://ufdc.ufl.edu/UFE0021336/00001

Material Information

Title: Palatability and Efficacy of Emamectin Benzoate Gel Baits on Four Pest Cockroach Species
Physical Description: 1 online resource (93 p.)
Language: english
Creator: Bayer, Barbara E
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2007

Subjects

Subjects / Keywords: american, americana, averse, bait, blatta, blattella, brownbanded, cockroach, gel, german, germanica, longipalpa, oriental, orientalis, periplaneta, supella
Entomology and Nematology -- Dissertations, Academic -- UF
Genre: Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Four species of pest cockroaches, the German, Blattella germanica, the brownbanded, Supella longipalpa, Oriental, Blatta orientalis and American, Periplaneta americana, were fed gel baits containing emamectin benzoate to determine relative palatability and efficacy. Emamectin benzoate gel baits were formulated as either emamectin A or emamectin B at concentrations of 0.05%, 0.1%, or 0.2%. For all cockroaches tested, there was no significant difference in palatability or efficacy between emamectin A 0.1% or emamectin B at 0.05%, 0.1% or 0.2%, with the exception of percent mortality of American cockroaches; emamectin B 0.05%, which had the lowest percent mortality, was significantly different from emamectin A 0.1%. Two German cockroach strains, the Daytona bait averse strain and the Orlando normal susceptible strain, of German cockroach were fed a set of experimental gel baits, emamectin A and B at 500 ppm (0.05%) and 1000 ppm (0.1%) emamectin benzoate. There was no significant difference in palatability of baits between strains; both strains consumed similar percentages of gel bait and dog food. Percent mortality from consumption of emamectin gel baits was between 80% and 90% at 6 d. A second set of experimental emamectin gel baits formulated at 0.05%, 0.1%, or 0.2% emamectin benzoate were fed to the Daytona German cockroach stain, brownbanded cockroaches, Oriental cockroaches and American cockroaches in order to determine palatability and efficacy. The emamectin gel baits were palatable to all four species. Only brownbanded cockroaches consumed similar percentages of gel bait and dog food. The other three species preferred the emamectin gel baits over dog food, with 78% to 99.7% of total consumption being emamectin gel baits. All four species were highly susceptible to the emamectin gel baits with 85% to 99% mortality at 14 d. Percent mortality from emamectin gel baits was similar to Maxforce FC Select for the Daytona German cockroach strain and brownbanded cockroach. For the Oriental cockroach, percent mortality from emamectin gel baits, emamectin A 0.1% and emamectin B 0.1% and 0.2%, was similar to Maxforce FC Select at 14 d. For American cockroaches, there were no statistical differences between Maxforce FC Select and the emamectin gel baits, emamectin A 0.1% or emamectin B 0.2%, with 98.6% and 96.4%, respectively, at 14 d. All formulations and dosages of emamectin gel baits were palatable to all cockroach species tested. Additionally, when fed emamectin gel baits, high susceptibility, 85% to 99.5% mortality, was observed for all pest cockroaches tested at 14 d. Therefore, cockroach gel baits containing emamectin benzoate show excellent potential for controlling pest cockroaches.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Barbara E Bayer.
Thesis: Thesis (M.S.)--University of Florida, 2007.
Local: Adviser: Koehler, Philip G.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2008-08-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2007
System ID: UFE0021336:00001


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PALATABILITY AND EFFICACY OF EM AMECTIN BENZOATE GEL BAITS ON FOUR PEST COCKROACH SPECIES By BARBARA ELLEN BAYER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2007 1

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2007 Barbara Ellen Bayer 2

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To my family and friends. Thank you for all of your support. 3

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ACKNOWLEDGMENTS I thank my chair, Dr. Phil Koehler, and me mbers of my committee, Drs. Richard Patterson, Michael Scharf, and Deanna Branscome, for a ll their help. I thank everyone in the Urban Entomology Laboratory for their constant support and Syngenta Corporation for its generous support. I thank my parents, Bette and Jim, my family and friends for their encouragement, without whom none of this would be possible. 4

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TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF TABLES ...........................................................................................................................8 LIST OF FIGURES .........................................................................................................................9 ABSTRACT ...................................................................................................................................10 CHAPTER 1 INTRODUCTION................................................................................................................. .12 2 LITERATURE REVIEW.......................................................................................................14 Pest Status...............................................................................................................................14 Aesthetics........................................................................................................................15 Health......................................................................................................................... .....15 Pest Cockroaches....................................................................................................................16 Domestic Cockroaches...........................................................................................................17 German Cockroach..........................................................................................................18 Distribution...............................................................................................................18 Habitat and ecology..................................................................................................18 Physical characteristic..............................................................................................18 Life cycle..................................................................................................................19 Brownbanded Cockroach................................................................................................20 Distribution...............................................................................................................20 Habitat and ecology..................................................................................................20 Physical characteristic..............................................................................................20 Life cycle..................................................................................................................21 Peridomestic Cockroaches......................................................................................................2 1 American Cockroach.......................................................................................................22 Distribution...............................................................................................................22 Habitat and ecology..................................................................................................22 Physical characteristic..............................................................................................23 Life cycle..................................................................................................................23 Oriental Cockroach..........................................................................................................24 Distribution...............................................................................................................24 Habitat and ecology..................................................................................................24 Physical characteristic..............................................................................................25 Life cycle..................................................................................................................25 Control Methods.....................................................................................................................26 Synthetic Insecticides......................................................................................................26 Sodium channel........................................................................................................27 Chloride channels.....................................................................................................28 5

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Acetylcholine receptors............................................................................................28 Acetylcholinesterase inhibitors................................................................................29 Insect growth regulators...........................................................................................29 Mitochondrial toxins................................................................................................29 Natural Insecticides.........................................................................................................29 Formulations................................................................................................................... .30 Wettable powders.....................................................................................................30 Emulsifiable concentrates (EC)................................................................................31 Microencapuslation..................................................................................................31 Dusts.........................................................................................................................31 Baits..........................................................................................................................32 Resistance...............................................................................................................................32 Biochemical Resistance...................................................................................................33 Behavioral Resistance.....................................................................................................33 Glucose aversion......................................................................................................34 Multiple sugar aversion............................................................................................35 Avermectins.................................................................................................................... ........36 Mode of Action................................................................................................................36 Development.................................................................................................................... 36 Emamectin Benzoate.......................................................................................................37 3 EMAMECTIN BENZOATE ON ORLANDO AND DAYTONA STRAINS OF GERMAN COCKROACH.....................................................................................................39 Introduction................................................................................................................... ..........39 Materials and Methods...........................................................................................................41 Insecticides......................................................................................................................41 Insects..............................................................................................................................41 Assay Setup.....................................................................................................................42 Assay Method..................................................................................................................42 Data Analysis...................................................................................................................42 Results.....................................................................................................................................43 Consumption.................................................................................................................... 43 Mortality..........................................................................................................................44 Discussion...............................................................................................................................44 4 EMAMECTIN BENZOATE ON DOMESTIC COCKROACHES.......................................52 Introduction................................................................................................................... ..........52 Materials and Methods...........................................................................................................54 Insecticides......................................................................................................................54 Insects..............................................................................................................................54 Assay Setup.....................................................................................................................55 Assay Method..................................................................................................................55 Data Analysis...................................................................................................................56 6

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Results.....................................................................................................................................56 Consumption.................................................................................................................... 56 Mortality..........................................................................................................................57 Discussion...............................................................................................................................58 5 EMAMECTIN BENZOATE ON PE RIDOMESTIC COCKROACHES..............................67 Introduction................................................................................................................... ..........67 Materials and Methods...........................................................................................................69 Insecticides......................................................................................................................69 Insects..............................................................................................................................69 Assay Setup.....................................................................................................................70 Assay Method..................................................................................................................70 Data Analysis...................................................................................................................71 Results.....................................................................................................................................71 Consumption.................................................................................................................... 71 Mortality..........................................................................................................................72 Discussion...............................................................................................................................73 6 CONCLUSION................................................................................................................... ....81 LIST OF REFERENCES...............................................................................................................83 BIOGRAPHICAL SKETCH.........................................................................................................93 7

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LIST OF TABLES Table page 3-1 Gel bait preference by Blattella germanica nymphs (Orlando and Daytona strains) in a 24 h choice experiment...................................................................................................48 3-2 Mortality 6d after bait placement of Blattella germanica nymphs (Orlando and Daytona strains).................................................................................................................49 4-1 Gel bait preference by Supella longipalpa mixed population, and Blattella germanica nymphs (bait averse Daytona stra in) in a 24 h choice experiment..................62 4-2 Percent mortality of Supella longipalpa mixed population, and Blattella germanica nymphs (bait averse Daytona st rain) 14 d after bait introduction......................................63 5-1 Gel bait preference of Blatta orientalis and Periplaneta americana in a 24 h choice experiment..................................................................................................................... .....77 5-2 Percent mortality of Blatta orientalis and Periplaneta americana at 14 d after bait introduction........................................................................................................................78 8

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LIST OF FIGURES Figure page 3-1 Percent mortality at 3 and 6 d afte r bait placement for the Orlando strain of Blattella germanica nymphs.............................................................................................................50 3-2 Percent Mortality at 3 and 6 d after bait placement for the Daytona strain of Blattella germanica nymphs.............................................................................................................51 4-1 Percent mortality for Supella longipalpa at 3, 6, 8 and 14 d after introduction of emamectin gel baits............................................................................................................ 64 4-2 Percent mortality for Blattella germanica nymphs (bait averse Daytona strain) at 2, 4, 7 and 14 d after introduction of emamectin gel baits.....................................................65 4-3 Percent consumption for Supella longipalpa cockroach, at increasing concentrations of emamectin benzoate......................................................................................................66 5-1 Percent mortality for Periplaneta americana at 3, 6, 8 and 14 d after introduction of experimental emamectin benzoate baits............................................................................79 5-2 Percent mortality for Blatta orientalis at 3, 6, 8 and 14 d after introduction of bait.........80 9

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Abstract of Thesis Presen ted to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Master of Science PALATABILITY AND EFFICACY OF EM AMECTIN BENZOATE GEL BAITS ON FOUR PEST COCKROACH SPECIES By Barbara Ellen Bayer August 2007 Chair: Philip G. Koehler Major: Entomology and Nematology Four species of pest cockroaches, the German, Blattella germanica, the brownbanded, Supella longipalpa Oriental, Blatta orientalis and American, Periplaneta americana, were fed gel baits containing emamectin benzoate to determine relative palatability and efficacy. Emamectin benzoate gel baits were formulated as either emamectin A or emamectin B at concentrations of 0.05%, 0.1%, or 0.2%. For all cockroaches tested, there was no significant difference in palatability or efficacy between emamectin A 0.1% or emamectin B at 0.05%, 0.1% or 0.2%, with the exception of percent mortality of American cockroaches; emamectin B 0.05%, which had the lowest percent mortality, was si gnificantly different from emamectin A 0.1%. Two German cockroach strains, the Daytona bait averse strain and the Orlando normal susceptible strain, of German cockroach were fe d a set of experimental gel baits, emamectin A and B at 500 ppm (0.05%) and 1000 ppm (0.1%) emamectin benzoate. There was no significant difference in palatability of ba its between strains; both strains consumed similar percentages of gel bait and dog food. Percent mortality from co nsumption of emamectin gel baits was between 80% and 90% at 6 d. A second set of experimental emamectin ge l baits formulated at 0.05%, 0.1%, or 0.2% emamectin benzoate were fed to the Daytona German cockroach stain, brownbanded 10

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cockroaches, Oriental cockroaches and American cockroaches in order to determine palatability and efficacy. The emamectin gel baits were pala table to all four species. Only brownbanded cockroaches consumed similar percentages of gel bait and dog food. The other three species preferred the emamectin gel bait s over dog food, with 78% to 99.7% of total consumption being emamectin gel baits. All four species were highl y susceptible to the emamectin gel baits with 85% to 99% mortality at 14 d. Percent mortality from emamectin gel baits was similar to Maxforce FC Select for the Daytona German co ckroach strain and brownbanded cockroach. For the Oriental cockroach, percent mortality fr om emamectin gel baits, emamectin A 0.1% and emamectin B 0.1% and 0.2%, was similar to Maxforce FC Select at 14 d. For American cockroaches, there were no statistical differe nces between Maxforce FC Select and the emamectin gel baits, emamectin A 0.1% or emamectin B 0.2%, with 98.6% and 96.4%, respectively, at 14 d. All formulations and dosages of emamectin gel baits were palatable to all cockroach species tested. Additionally, when fed emamectin gel baits, high susceptibility, 85% to 99.5% mortality, was observed for all pest cockroaches te sted at 14 d. Therefore, cockroach gel baits containing emamectin benzoate sh ow excellent potential for c ontrolling pest cockroaches. 11

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CHAPTER 1 INTRODUCTION Cockroaches are known to carry certain fungi, viruses, and b acteria, which cause specific diseases in humans. Additionally, cockroaches produce allergens that can elicit asthma attacks. Worldwide, approximately 300 million people suffer from asthma. More than 250,000 deaths per year are attributed to asthma and this number is expected to increas e by ~20% over the next decade (WHO 2006). The urbanization of people ar ound the world, from rural communities into large crowded cities, has been blamed for some of the increased occurrences of asthma. This may be due to increased exposure to pest cockroac h allergens. Because of the risk they pose to human heath, cockroaches are c onsidered serious urban pest. Most cockroaches are feral, rarely encountering humans; however, other cockroaches live in close association with humans and these cockroaches are considered the worst pests. Those most commonly encountered are the German, Blattella germanica L., brownbanded, Supella longipalpa (Fabricius), Oriental cockroach, Blatta orientalis L. and American Periplaneta americana L. cockroaches (Whitney et al. 1967, Corn well 1968, Reierson et al. 1979, Darr et al. 1998, Capinera 2004). Cockroach control is commonly accomplished with the use of insecticides. With repeated application of an insecticide, insecticide re sistance becomes an issue. Consequently, new insecticides must be tested to combat the resist ance. Insecticides are available in a variety of formulations, such as sprays, dusts, and more re cently, gel baits. Each formulation has positive and negative attributes. With sprays, there is in creased insecticide exposure to humans as well as environmental degradation of the insecticide due to heat or moisture. Dusts can have a long residual, but can become airborne and will clump if exposed to too much moisture. Gel baits, which are increasingly relied upon fo r cockroach control, can be us ed in sensitive areas where 12

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other formulations cannot be used, and limit th e amount of insecticide in the environment. However, some cockroach strains have developed an aversion to some of the ingredients in gel baits; therefore, their matrices must be altered to overcome the aversion. In my study, I tested two sets of experime ntal cockroach gel bait matrices with a novel insecticide, emamectin benzoate, were tested against the most commonly encountered pest cockroach species. In the first study, an experime ntal gel bait matrix, with emamectin benzoate, was found to be palatable to both a bait averse strain of German cockroaches as well as a normal strain. Additionally, the percen t mortality caused by consumption of emamectin benzoate, on these two strains of German cockroaches was test ed. In the subsequent studies, a second set of experimental gel bait matrices, also containing emamectin benzoate, were used to determine palatability and susceptibility of a bait averse strain of German cockroach, as well as the brownbanded cockroach, the Oriental co ckroach, and the American cockroach. 13

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CHAPTER 2 LITERATURE REVIEW Four hundred million yeas ago, 150 million year s before dinosaurs appeared, the first arthropods (springtails, spiders, and scorpions) were roaming th e earth. Cockroaches entered the fossil record 300-360 million years ago and have remained nearly unchanged in appearance (Blatchley 1920, Appel 1995 Rust et al. 1995, Copeland 2003, Kendall 2005). Of the more than 4,000 described species of cockroaches that currently inhabit the earth (Bell 1984, Mabbett 2004), only 69 live in North America (Atkinson et al. 1991) and of these, just a few are considered pests. All cockroaches are hemimetabolous. They undergo three life stages: egg, nymph, and adult. Cockroach eggs are enclosed in an ooth eca which can be carried by the gravid female for a few hours and then dropped or glued to a surface or the ootheca can be carried until nymphal hatch (Mullins and Cochra n 1987). Nymphs are similar in appearance to adults but are wingless. Nymphal development is punctuated by molts, the final molt ending in adulthood. Incubation time of oothecae and nymphal develo pment are both temperature and nutrient dependent, with warmer temperatures increasing the rate of development. Pest Status Pest cockroaches are those that live and br eed in and around human structures (Cornwell 1976). Their natural habitat is outdoors and it is the fault of humans that pest cockroaches exist. We encourage them to co me indoors, by providing them w ith an environment similar to their natural habitat. Once inside, these cockroaches are considered pests for both aesthetic and health reasons. 14

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Aesthetics Cockroaches are messy. Their fecal matter stai ns and discolors surfaces in addition to creating unpleasant odors that humans can detect. They defecate for obvious biological reasons, as well as to communicate. Pheromones in feces a ssist cockroaches in locating aggregations and can send signals to attract mates. The sex phero mones, periplanone A and B, of the American cockroach, Periplaneta americana L, were isolated from fecal material (Persoons et al. 1982). However, sex pheromones are also found in the cuticle like those of the German cockroach female, Blattella germanica L. (Schal et al. 1990). These cu ticular compounds require physical contact before a sexual response occurs (Cha rlton et al. 1993). In addition to carrying pheromones, cockroach feces and their cuticle can also be the source of health problems for humans. Health Humans can develop physical and psychological problems due to the presence of cockroaches. Inner city children with asthma, who we re given skin tests, had a greater reaction to cockroach allergens than to dust mite or cat alle rgens (Rosenstreich et al 1997). More than 80% of the childrens bedrooms had so me detectible level of cockroach allergen and 50% had levels high enough to induce an asthma attack. According to Brenner et al. (199 0), cockroach allergens are second, only to house dust mites, in causing r eactions in asthmatics. This is especially important considering that million people suffer from asthma and 255,000 people died from asthma in 2005 (WHO 2006). Cockroaches are able to carry, maintain, and excrete viable fungi, protozoa, eggs of helminthes, viruses, and bacteria. This includes several strains of stre ptococcus and salmonella (Roth and Willis 1957, 1960). While it is difficu lt attribute human illness directly to 15

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cockroaches, correlations have b een made that implicate them. Brenner et al. (1987) reviewed several instances, which link cockroaches to dise ases including an outbreak of typhus on a ship, gastroenteritis in a hospital, and dysentery in Northern Ireland. Another case, which implicates cockroaches in the spread of disease, Tarshis (1962) describes decrea ses in the spread of hepatitis in a housing project. The decrease, in this particular housing project, coincided with insecticide treatments and documented decreases in cockroach infestations. At the same time, hepatitis cases were increasing in the immediat e area suggesting that cockroaches were helping transmit hepatitis. Cockroaches can also cause psychological problems; people are embarrassed to have them. Cornwell (1976) stated that fear or sham e associated with cockroach infestations prevented some people from admitting infestation even existed. The fear or shame can cause stress in proportion to the si ze of the cockroach and/or infe station (Brenner 1995). The stress comes from the implication that if cockroaches are present it is due to an unsanitary environment, which may or may not be the case. Pest Cockroaches Of the thousands of described species of cockroaches, there are only a few that are considered pest cockroaches. Cockroaches with a pest status are those in close association with humans. Four primary pest species are German cockroach brownbanded cockroach, Supella longipalpa (Fabricius), Oriental cockroach, Blatta orientalis L., and American cockroach (Whitney et al. 1967, Cornwell 1968, Reierson et al. 1979, Darr et al. 1998, Capinera 2004). Pest cockroaches are divided into two groups, domestic and peridomestic cockroaches, based upon where they live and breed. Domestic cockroaches are found mostly indoors while peridomestic cockroaches can be found outdoors as well as indoors. 16

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Domestic Cockroaches Domestic cockroaches almost exclusively live an d breed indoors (Darr et al. 1998). They are completely depend on the human habitat fo r survival and there may be co-evolution between humans and the domestic cockroach es (Barcay 2004). While both, brownbanded cockroaches and German cockroaches, are foun d throughout the United States, the German cockroach poses the larger pest problem because it is encountered more often. Domestic cockroaches can enter homes by a va riety of methods. In apartment homes or condominiums, there can be movement from one adjacent unit to another via shared plumbing (Owens and Bennett 1982) and through wall and cei ling voids. Additionally, oothecae, as well as live individuals, can be transported from one lo cation to another in paper bags, cardboard boxes, and furniture (Cornwell 1968, Barcay 2004). Many homes and business establishments become infested with German cockroaches when they ar e introduced inside infe sted cartons, foodstuffs, and other materials (Barcay 2004). Once cockroach es are introduced, the availability of food, water, and harborage encourage infestation, espe cially where sanitation practices are poor. Food can come from dirty dishes left in the sink or from meals eaten at vari ous locations within a structure such as a bedroom, living room, at a de sk, etc. Water is obtained from leaking pipes, condensation on plumbing, pet water bowls, or drip pa ns in refrigerators. Ha rborage, in general, can be any clutter such as boxes, papers, furnitu re, appliances, and cracks and crevices. Gravid German cockroaches prefer cracks 4.77 mm in width and nymphs prefer cracks as narrow as 1.59 mm (Koehler et al. 1994). 17

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German Cockroach Distribution Originating in Asia (Atkinson et al. 1 990, Appel 1995), the German cockroach has a worldwide distribution and is considered to be one of the worst insect pests (Blatchley 1920) in heated structures (Cornw ell 1968, Ross and Mullins 1995). Cornwell (1968) attributed its distribution to human commerce a nd war, suggesting that the German cockroach stowed away with humans as they traversed the globe. Habitat and ecology German cockroaches prefer a warm, moist environment (Cornwell 1968) where they have daily access to water (Barcay 2004). This includes house s, apartments, restaurants, supermarkets, food processing plants, motor vehicles, as well as naval and cruise ships (Cornwell 1968, Barcay 2004, Metzger1995). Kitchen and bathr oom areas are often preferred harborage sites and large aggregations have been located around refrigerators, stoves, and trashcans (Appel 1995). In heavy infestations, German cockroaches are found throughout structures and are rarely found living outdoors (Cornwell 1968, Appel 1995). Physical characteristic The one of the more distinguishing characte ristic of German co ckroaches are the two dark brown longitudinal parallel bands on the yellowish-brown pronotum (Blatchley 1920, Guthrie and Tindall 1968, Barcay 2004). On the la te instar German cockroach nymphs, the dark brown bands extend to the mesonota and metanota; the abdomen is also dark brown. Early instar nymphs have a single yellowish -brown spot may be present on the mesonota and metanota with the rest of the body a dark brown color. 18

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Adult German cockroaches possess non-functiona l wings that extend to the tip of the abdomen. The males are 10-13 mm in length and slende r, with the abdomen tapering to the tip of the posterior. The females are slightly darker in color and longer, 12-15 mm, as well as broader (Blatchley 1920, Guthrie and Ti ndall 1968). The female wings c over the abdomen and extend to just beyond the tip. The ootheca, when pr esent, is 8 mm long and light brown. Other members of the genus Blattella have similar characteristic to the German cockroach. Blattella vaga Hebard has a brownish-black colo red marking on the head, from the vertex to the clypeus, which distinguishes it fr om the German cockroach. The Asian cockroach, Blattella asahinai Mizukubo, is nearly identical to the German cockroach. However, the Asian cockroach is a strong flier and peridomestic or feral (Barcay 2004). Specific morphological differences between the German cockroach and Asian cockroach have been described (Roth 1986, Appel 1995, Richman 2000). Additionally, Ca rlson and Brenner (1988) described a method for discriminating Asian cock roaches, German cockroaches and B. vaga by means of gas chromatography for the quantitative determin ation of cuticular hydrocarbon components. Life cycle Female German cockroaches carry their ootheca, which contains 30 to 40 embryos, until just prior to hatching. Incubation requires ~ 28 d. Successive oothecae contain fewer developing embryos (Cornwell 1968, Ross and Mullins 1995). Nymphs require an average of 103 d to go through the 6-7 molts before reaching adulthood (B arcay 2004). The adult female will mate ~5 d after emergence and, generally, one mating is sufficient to fertilize all th e eggs she will produce (Ross and Mullins 1995). She will create her firs t ootheca 7 to 10 d after adult emergence. The adult female can live for five to 10 months and produce an average of five oothecae. Males have a shorter life span and can live for three to five months (Ross and Mullins 1995, Barcay 2004). 19

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Brownbanded Cockroach Distribution Brownbanded cockroaches are believed to have originated in Africa (Atkinson et al. 1990). First discovered in Florid a in 1903, it has since been f ound throughout the continental United States as well as tropical and subtropical regions of the world (Blatchley 1920, Cornwell 1968, Atkinson et al. 1990, Barcay 2004). Brownbande d cockroaches distribut ion is attributed to its tendency to hide in and at tach egg cases to furniture with subsequent movement of humans (Cornwell 1968, Pest Management 1989, Rust et al. 1995, Barcay 2004). Habitat and ecology Brownbanded cockroaches inhabit homes, apar tments, hotel, and hospital rooms" more than stores, restaurants, and kitchens (Pest Management 1989). They are only found outdoors in Africa (Cornwell 1968). Brownba nded cockroach water requirement is much lower than that of German cockroaches, and preferring warm, 27C, and dry areas. These factors allow them to infest diverse locations within a building such as bedrooms, shelves, spaces behind pictures, ceiling voids, light fixtures, elect ronics, and inside all types of furniture (Cornwell 1968, Pinto 1988, Barcay 2004, Capinera 2004). Physical characteristic The most distinguishing marks on the brow nbanded cockroach are their lateral creamcolored strips, which are visible in both nymphs and adults. These strips transverse, or nearly transverse, dark brown regions on the apical portion of the wings on adults. On the nymphs, the bands run across the posterior margin of the mesonotum and the first abdominal segment (Cornwell 1968). Nymphs have amber colored a bdomens. The pronotum, for both the adults and nymphs are dark brown with clear margins and cream-colored legs. There can be a great amount 20

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of color variation within th e species (Blatchley 1920, Co rnwell 1968); however, males are generally a lighter in color than the females. Males are also more slender than females and about 13-14.5 mm long. Their wings extend to cover the tip of the abdomen. The females are slightly smaller than the males in length, 10-12 mm, but have much broa der abdomens. The wings on the female do not cover the abdomen, but leave the sides and tip exposed. The ootheca is ~5 mm in length and has a reddish-brown to yell owish tint (Cornwell 1968, Barcay 2004). Life cycle Females will carry the ootheca, which contains up to 18 embryos, for 24 to 36 hours, then will attach it an object in a protected location. Incubation re quires an average of 70 d. Nymphs go through six to eight molts, whic h require an average of 160 d. Females mate three days after adult emergence and produce their first egg case about seven days later. She can produce up to 14 oothecae and live for three months. The male s will mate about five days after adult emergence and live for four months (Cornw ell 1968, Pest Management 1989, Barcay, 2004). Peridomestic Cockroaches Peridomestic cockroaches are found living and breeding outdoors around structures as well as, indoors (Darr et al. 1998) Outdoors, peridomestic cockro aches are found near structures, in sewers, under leaf detritus, stones, bark, in tree holes, palm trees, woodpiles, pine mulch, and vegetation (Suiter et al. 1992). They can move indoor s in a variety of ways such as via cracks and crevices in the foundation of a structure. Additionally gaps around doors, windows, and plumbing are easily accessible to these cockroaches. It is also possible to transport them inside with laundry or food packaging. Once inside, cond itions that help establish and maintain an infestation are access to food, water and harborag e. Food may consist of foodstuffs thrown away 21

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in a trashcan to the glue used in books. Water can come from condensatio n on pipes, leaky pipes, or drip pans in refrigerators. American Cockroach Distribution The American cockroach originated in Af rica (Cornwell 1968, Roth 1982, Atkinson et al. 1990). Its spread from Africa was greatly aided by commerce, as this cockroach is the most common one found on ships (Blatchley 1920, Corn well 1968, Barcay 2004). It has been introduced to most countries of the world and is widely distributed in tropical and subtropical regions (Blatchley 1920, Corn well 1968, Bell 1984). According to Bell (1984), the American cockroach lives outdoors in tropical and subtr opical regions and indoors in temperate regions. Habitat and ecology The American cockroach is most commonly associated with sewer systems but can be found under leaf debris, woodpiles, mulch, dumps, latrines, palm trees, sheds, and alleys (Cornwell 1968, Roth 1982, Barcay 2004). They can also occur in greenhouses where they will feast on young plants (Blatchley 1920). The Am erican cockroach will move indoors. Once inside, it is associated with basements and area s where food is prepared or stored (Cornwell 1968, Barcay 2004). This can include restaurants, grocery stores, bakeries, as well as factories, hospitals, hotels and zoos (Cornwell 1968, Barcay 2004). According to Barcay (2004), they are active at temperatures of 21 C and temperatures below -6 C will kill them. However, it has been reported that active American cockroaches have been found in trash heaps that were covered with snow (Barcay 2004). 22

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Physical characteristic The most distinguishing feature of American cockroaches is their pronotum, which has a brown bilobed spot surrounded by pale yellow (Blatchley 1920). Their wings are a reddishbrown and in the male, the wings extend beyond the tip of the abdomen. On the female, the wings just reach the tip of the abdomen (Blatchley 1920, Cornwell 1968, Guthrie and Tindall 1968, Barcay 2004). The females, which average 34.7 mm in length, are slightly longer and broader than the males, which average 33.6 mm in length (Barcay 2004). According to Cornwell (1968), nymphs in the first to fifth instars are a uniform brown color. From the sixth instar on, pale patches appear on the pronotum. Periplaneta spp. are similar in appearance, however ; they can be distinguished from each other. The American cockroach is slightly larger has thin cerci, and brownish-yellow legs while P. australasiae (Fabricius), P. fuliginosa (Serville), and P. brunnea Burmeister are all slightly smaller, have thicker cerci, and have dark brown legs. Additionally, P. australasiae has bright yellow markings surrounding a sharply defined bilobed black spot on the pronotum as well as bright yellow basal margins on the wings (Cornwell 1968). Periplaneta fuliginosa are uniformly dark brown on pronotum and wings. Finally, P. brunnea, which is the most similar in appearance to the American cockroach, can be di stinguished by the dark brown coloration of the wings. Furthermore, P. brunnea has a pale yellow pronotum, like that of the American cockroach, however, the brown spots on the pronotu m are less defined and touch the margins. Life cycle Female P. americana will carry the ootheca, which contains up to 16 embryos, for a few hours to several days (Cornwell 1968, Barcay 2004). The female will attempt to conceal oothecae, possibly by digging a hole in a substrate (soil, wood, or cardboard) and then covering 23

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the hole with debris which is held in place by her salvia (Roth 1982). Incubation requires an average of 44 d. Nymphal development takes ~600 d during which nymphs go through 10-13 molts (Cornwell 1968, Barcay 2004). The female will produce her first ootheca ~13 d after adult emergence and can live for three mont hs up to two years. Adult male P. americana can live for three months up to about a year. Oriental Cockroach Distribution Described by Blatchley (1920) as the mo st noisome and disagreeable insects, the Oriental cockroach is believed to have orig inated in North Africa and spread by means of commerce (Cornwell 1968). According to Atkinson et al. (1990), the Oriental cockroach is found in 20 of the 48 contiguous states, but not in Florida or most of the rest of the Southeastern United States. They can be found in two South Ameri can countries, Chile and Argentina (Cornwell 1968), and in more temperate regions of the world. Habitat and ecology Oriental cockroaches are located in and around structures, prefer cooler temperatures, and are most active at 20 29 C (Cornwell 1968). Out doors, they gravitate to moist areas in the shade such as under leaf debris, stones, and tree bark, as well as in lumber and trash piles (Cornwell 1968, Pest Management 1995). Oriental cockroaches are relativel y cold tolerant and can survive at 2C for more than 42 d (le Pa tourel 1993). The Oriental cockroach can move indoors by way of laundry, food packaging, and ga ps around doors, windows, or pipes, and cracks in the foundation (Thoms and Robins on 1986, Pest Management 1995, Barcay 2004). Indoors, they prefer moist, damp, cool areas such as crawl spaces and basements (Blatchley 1920, Pest Management 1995, Barcay 2004). They are also found in warmer areas such as wall 24

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and porch voids (Thoms and Robinson 1986, Pest Management 1995) as well as around radiators, ovens, and hot-water pipes (C ornwell 1968). The Oriental cockroach can use garbage chutes, electrical conduits, and plumbing to move from lower areas of a structure to upper levels (Pest Management 1995). Physical characteristic Adult and nymph Oriental cockroaches are a ve ry dark brown to blac k, giving rise to the common name of black beetle in England. Or iental cockroach males are 17-29 mm in length and have wings that extend and cover of their abdomen (Guthrie and Tindall 1968, Pest Management 1995, Barcay 2004).The females aver age 32 mm in length and their wings are reduced to pads. The adult female can be dist inguished from nymphs by the venations on her wing pads. The nymphs have no distinguishin g marks (Pest Management 1995). The ootheca is ~10 mm in length and a dark reddish-brown (Cornwell 1968, Barcay 2004). Life cycle A field collected strain of Oriental cockroach maintained within the lab at 27 C and 45% relative humidity was observed (Short and Ed wards 1991). According to this study, Oriental cockroach females carry their ootheca, which contains ~14 embryos, for 24 to 36 hours. She then either drops or glues the ootheca somewher e warm and near food (Pest Management 1995, Barcay 2004). Incubation requires ~45 d. Male ny mphal development requires about six and a half months during which time they go th rough seven to nine molts. Female nymphal development requires an additional month and eight to 10 molts. The female will produce her first ootheca 12 d after adult emergence and she can live for up to three months. The males can live slightly longer, up to four months. 25

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Most other sources indicate that the number of embryos per ootheca is 16 (Barcay 2004, Blatchley 1920, Pest Management 1995). However, Short and Edwards (1991) stated that while the Oriental cockroaches biology had been well documented, there was a surprising amount of contradiction in the literature about several aspects of the developmental and reproductive biology of this species. They ran their experi ments at 27 C, which Cornwell (1968) reported was in the preferred temperature range of Oriental cockroach activity. Cornwell (1968) however, reported biology averages taken at temperatures of 30-36 C, well out of the preferred temperature range for Oriental cockroach activ ity, which seems to support Short and Edwards assertion. Control Methods For no other insects have so many quack remedies been urged and are so many newspaper remedies published In fact, ra ther than put faith in half of those which have been published, it were better to rely on th e recipe current among the Mexicans: Catch three (cockroaches) and put them in a bottle and so carry them to where two roads cross. Here hold th e bottle upside down, and as they fall out repeat aloud three credos. Then all the cockroaches in the house for which these three came will go away (Blatchley 1920). Cockroach pests need to be controlled because of the risks they pose to human health. Most insecticides used to control cockroaches disrupt in sect nervous systems; ot hers can interfere with the cuticle and even interrupt th e process of molting into adulthood. Consideration of insecticidal mode of action is important when trying to control cockroaches. Synthetic Insecticides After World War II, synthetic insecticides we re developed extensively to control insect pest, such as cockroaches. There are varieties of modes of action for the numerous synthetic insecticides. 26

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Sodium channel Sodium channels are voltage gated and when stimulated to open they allow the influx of sodium ions, which can cause excitatory reactions in the nervous system. Pyrethroids are synthetic versions of naturally occurring pyrethrin insecticides. Pyrethroids are some the most common insecticides and there are a large num ber of them including, allethrin, cyfluthrin, lambda-cyhalothrin, delthmethrin, and permethri n. They function as sodium channel agonists, binding to the channel and causing neuron-excitation, which results in rigid paralysis. There are two generations of pyrethroids. Type I pyrethroids do not contain an -cyano group, they have a fast knockdown, and but little residual activity. Type II pyrethroids have an -cyano group, a slower knockdown, and longer residual activity (Barcay et al. 2004, Yu 2007). Oxidiazine, which includes the active i ngredient indoxacarb, is a relatively new insecticide that functions at the sodium channel as an antagonist. It binds to the sodium channel, holding it closed, which results in flaccid para lysis. Indoxacarb is ca lled a pro-insecticide because it is relatively inert until ingested. Once insi de the insect, it is metabolized to its toxic from N -decarbomethoxyllated metabolite (DCJW) (Yu2007). Dichloro-Diphenyl-Trichloroethane (DDT), an organochlorine, func tions at the sodium channel as an agonist. It binds to the channel and causes neuronexcitation resulting in rigid paralysis. It was first synthesized in 1874; how ever, its insecticidal activity was not discovered until about 1940 (Cornwell 1976, Yu 2007). Both a dust and a spray formulation were used extensively during and after WWII, for contro l of everything from body lice to mosquitoes (Cornwell 1976). However, not all organoc hlorines act on the sodium channels. 27

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Chloride channels Chloride channels are ligand gated and located in the central nervous system (CNS) as well as the peripheral nervous system (PNS). When stimulated, they open to allow chloride ions to enter and cause neuron-inhibition. The chloride channels open when glutamate in the PNS or -aminobutyric acid (GABA) in the CNS binds to the postsynaptic neuron. Cyclodeines, such as aldrin and chlordane, act on the GABA gated chlori de channels as antagonists. They bind to the channel and prevent chloride ions from ente ring, resulting in neur on-excitation and rigid paralysis. Phenylpyrazole, which includes the active ingredient fipronil, is also a chloride channel antagonist. It binds to the postsynaptic neuron preventing the infl ux of chloride ions. This causes an over stimulation of the ner vous system and rigid paralysis. However, Avermectins, such as abamectin and emamectin be nzoate, act as chloride channel agonists. They bind to the channel and prevent it from closing. This allows chloride ions to flow into the cell and results in neuron-inhibiti on and flaccid paralysis (Yu 2007) Avermectins are microbial lactones; however, not all insecticides in this class work on chloride channels. Acetylcholine receptors Acetylcholine (ACh), an excitatory neuro tr ansmitter in the central nervous system, is released from the presynaptic neuron; it cros ses the synaptic gap, and then binds to the postsynaptic neuron at the acetylcholine r eceptor (AChR). ACh is removed from the postsynaptic neuron by acetylc holinesterase (AChE). Spinos yn, another microbial lactone function as an agonist at the ni cotinic AChR. It binds to the receptor which results in neuro excitation and rigid paralysis. Nicotinoids, such as the ac tive ingredients nicotine and imidacloprid, also function as an agonist at the nicotinic AChR. 28

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Acetylcholinesterase inhibitors Organophosphates (OP), such as dichlorvos a nd chlorpyrifos, and carbamates, such as aldicarb and bendiocarb, function by mimicki ng ACh and binding to AChE. This makes AChE unavailable to ACh and causes neuro-excitati on and rigid paralysis (Barcay 2004, Yu 2007). Insect growth regulators Insect growth regulators, such as me thoprene and noviflumuron, do not act on the nervous system but instead interf ere with naturally occurring hormones within the insect. They can mimic juvenile hormone, ecdysone, or aff ect chitin synthesis, which can result in sterilization, malformations, and unsuccessful molting for th e insect (Barcay 2004, Yu 2007). Chitin synthesis can also affect a nymphs abilit y to molt successfully. In adults, it can cause females to abort oothecae and shorten th e life span of males (Barcay 2004). Mitochondrial toxins Other insecticides can interfer e with an insects ability to produce adenosine triphosphate (ATP), which is the main source of cellular energy (Campbell et al 2003). Some insecticides can act at one of several points with in the tricarboxylic acid (TCA) cycle. Other insecticides, such as hydramethylnon, can act at points on the electron transport chain, by inhibiting the flow of electrons down the chain, by inhibiting or uncoupling oxidative phosphorylation along the electron transport chain (Yu 2007). Natural Insecticides Natural insecticides are the oldest insecticides used for insect control. They have been used for well over a century (Reierson 1995). Prior to World War II, they were used extensively for cockroach control (Cornwell 1976). These we re inorganic materials, such as boric acid, diatomaceous earth, arsenic, phosphorus and sodium fluoride, as well as organic materials such 29

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as pyrethrins made from crushed dried Ch rysanthemum flowers (Cornwell 1976, Ebeling 1995, Barcay 2004). These materials were mixed with f ood to make baits or used as dusts. Inorganics can have long residuals and low resistance, but can also be slow acting (Bennett et al. 1988). Both, boric acid and diatomaceous earth act as cuticle disrupters. They are abrasive and absorptive to the insect cuticle. This has the affect of causing the insect to desiccate due to water loss. Phosphorous is an acetylc holinesterase inhibitor while, ar senic and sodium fluoride effect energy production. Use of natural insecticide dusts greatly d ecreased with the deve lopment of synthetic insecticide sprays, fogs and aerosols which we re less labor intense and had a faster speed of action (Ebeling 1995). With the onset of resistance to synthetic insecticides, dusts regained some popularity. Formulations Insecticides are dispersed by a variety formulations and one insecticide (active ingredient) can be used in more than one type of formulations. Each type of formulation has both positive and negative qualities. Therefore, consid eration should be taken when deciding which formulation to use in a given environment. Wettable powders Wettable powders (WP) consist of an active ingredient ad hered to a diluent with a wetting agent which are then suspended in wate r (Yu 2007). It is sprayed onto surfaces or injected into harborag es (Koehler et al. 1995, Barcay 2004). Wettable powders generally have good residual, especially on porous surfaces. Howeve r, they tend leave a visible residue on dark colored materials. 30

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Emulsifiable concentrates (EC) Emulsifiable concentrates (EC) consist of the active ingredient, a solv ent, and a surfactant mixed with water. Like WPs, ECs can be spraye d onto surfaces or into harborages. Unlike WPs, they do not stain surfaces. In addition, they do not adhere well to non-porous surfaces like stainless steel and ceramic tile and are absorb ed by porous surfaces. They can become unstable when applied on materials with high a pH (B arcay 2004), performing best on finished wood, vinyl tile and porcelain (Koe hler et al. 1995). Microencapuslation Microencapsulates consist of an active ingredients surrounded, or encapsulated, by plastic. The active ingredient is released over time. These insecticides generally have low odor and a long residual activity. While mortality can be observed within a few hours, it can require a couple of days for initial mortality. Since rele ase is slow and over time, cockroaches may be exposed to sub-lethal doses, th ereby decreasing the time required for insecticide resistance to develop (Koehler et al. 1995, Barcay 2004). Dusts One of the oldest formulations for delivering insecticide is dust. A dust generally consists of the active ingredient and a d iluent. Dusts are most often used in cracks and crevices (Yu 2007). They have a low odor and a long residual. Th ey can also be used around electrical outlets and equipment (Koehler et al 1995, Barcay 2004). Dust also have slow knockdown, they can drift, and are considered the most difficult of the cockroach control formulations to apply correctly (Koehler et al. 1995). 31

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Baits One of the more important formulations for cockroach control is baits. Baits have been used for more than a century and Blatchle y (1920) described a bait made from phosphorous paste, which contained sweetened flour paste and 1 2% phos phorus, which was to be spread on paper or cardboard and placed in the runways of the roaches. However, it was not until the early 1980s that cockroach baits (gel baits) were seriously considered for cockroach control. Gel baits consist of an active ingr edient, a feeding stimulant, and a carrier (Yu 2007). Gel baits can be used in sensitive areas where other formula tions are prohibited while reducing the amount of insecticide placed in the environment. Proper gel bait placement is important, since gel baits must often compete with other food sources. Additionally, use of other insecticides, especially repellants, on or around gel ba its can affect control. Resistance Resistance is the development and heritable abi lity of insects to tolerate doses of toxicants that would prove lethal to the majority of indi viduals in a normal population of the same species (Braness 2004) and which results in control failures. The first documented case of insecticide resistance was from Melander (1914). In 1908, sma ll populations of scale insects were still alive after sulfur-lime application. In 1910, about a 10% survival rate in the scale population was observed, this was followed by a 50% survival rate in 1912. This classic example shows how high selective pressure a nd natural genetic variation within a population can lead to resistance. Resistance can develop with any level of selec tion pressure. Selection pressure can include a variety of mechanism that can increase re sistance within a population (Hoy 1999): The repeated use of one insecticide, class of insecticides or insecticides with the same mode of action for a prolonged period. The treatment of a large geographical area with one insecticide Not leaving refugia of susceptible insects. 32

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Low migration. Treating all life stages w ith same insecticide. Multivoltine with overlapping generations Use of insecticides with long residuals. Not surprisingly, German cockroaches are subjecte d to most, if not all, of these selection pressures. Resistance mitigation may be possibl e; however, with increased selection pressure, resistance is generally considered inevitable (Hoy 1999). There are three ca tegories of resistance: biochemical, physiological, and behavioral (Geor ghiou 1972). For our purpose, only biochemical and behavioral resistance will be discussed. Bioc hemical resistance includes the detoxification of insecticides, enzyme activation, a nd decreased sensitivity of ta rget enzymes Georghiou (1972). While, behavioral resistance is the ability to de crease the duration of cont ract with toxicant and an alteration of host or habitat preferences. Biochemical Resistance The selective pressure placed on insects can re sult in biochemical resistance. Cytochrome P450 is one mechanism that increases insectic ide detoxification. Some insecticide resistant strains of German cockroaches have cytochrome P450 levels that were 2.5 and 4.5 fold higher than the cytochrome P450 level of a normal stra in of German cockroaches (Valles and Yu 1996, Scharf et al. 1998). In addition to insecticide detoxification, biochemical resistance can occur with target site insensitivity. Insensitivity of th e sodium channel was observed in an insecticide resistant stain of German cockroaches. Some of the pyrethroid resistan ce observed, as well as DDT cross-resistance, was attributed to targ et site insensitivity (Umeda et al. 1988). Behavioral Resistance Behavioral resistance in insect s is an action that allows a population to avoid contact with toxic compounds (Lockwood et al. 1984, Sparks et al 1989) and is a result of hypersensitivity or hyperirritability (Yu 2007). One example of behavioral resistance has been noted in the 33

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horn fly, Haematobia irritans (L.) (Byford et al. 1987, Sparks et al. 1989). Resi stance strains of the horn fly moved from face, shoulders and back to the bellies of ca ttle with pyrethroidsimpregnated ear tags. In another example, some strains of German cockroach refused to consume gel baits with certain sugars. Glucose aversion In 1993, Silverman and Bieman described a strain of German cockroaches that refused to consume gel baits. They found that there was not re pellency to the insecticide but rather to a sugar contained in the bait matrix. Several st rains had developed a behavioral resistance (aversion) to the consumption of glucose (Silverman and Ross 1994), a sugar that was previously considered a phagostimulant for a number of ins ects (Bernays 1985). It was determined that one gene was controlling the aversi on and it was an autosomal incompletely dominant trait, not linked to sex and the cockroaches that carried just one allele for the gene expressed the aversion (Silverman and Bieman 1993, Ross and Silverma n 1995). Silverman (1995) found that glucose avoidance had beneficial effects. When fed f ood containing no glucose, all three strains (a homozygous normal strain, a homozygous bait averse strain and a heterozygous mix of the bait averse and normal strains) were observed to have increases in the number of embryos per ootheca. Additionally, nymphs consumed more food, gained more weight, took less time to mature, and survived to adulthood in greater numbers compared to those fed an 18% glucose diet. It was not clear, whethe r the different populations of Ge rman cockroaches developed the aversion independently of each ot her or if the aversion develope d in a few strains that were transported to other regions. However, the aver sion issue was solved by replacing glucose in the gel baits with another sugar, such as fructose. 34

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Multiple sugar aversion By 1999, new cases of German cockroach gel bait aversion were appe aring in isolated locations within Florida, Texas, and New York (Morrison et al. 2004). The common thread was poor sanitation along with a heavy reliance on gel baits for control. By 2006, more than 50% of the pest control operators accounts were having aversion issues (Koehler 2006). Considering the previous case of bait aversion, an attempt was made to alter the sugar in the bait matrix to resolve the problem, but this was to no ava il (Barile 2003). Wang et al. (2004) found the sugar aversion problem varied from one strain of Germ an cockroaches to another. They tested three strains of German cockroaches (one normal lab re ared strain and two field collected strains) on six sugars (D-fructose, D-glucose, D-maltose, D-sucrose, D-lactose, D-galactose) to determine if the sugars were feeding stimulants or deterrents. They discovered that four of the six sugars (D-fructose, D-glucose, D-maltose, D-sucrose) were feeding stimulants to th e normal lab reared strain. Of the two field collected strains, all of the sugars were feeding deterrents in the strain which had been was collected from apartments where the only method of control, for the five years prior to collection, was gel baits. The other field coll ected strain, which had been subjected to pyrethroid sprays, gel baits, ba it stations and boric acid dusts by residents, contractors and researchers for the five years prior to collection, two of the sugars (D-maltose, D-sucrose) were stimulants, 1 (D-fructose) was neither stimulant nor deterre nt and the other three were deterrents. This suggests that, much like physiological resist ance to insecticides, the cockroaches with the greatest selection pressure exhibit a greater aversion to gel baits. The newest gel bait aversion, unlike the glucose aversion, ap pears to be partially sex linked, with female averse i ndividuals passing on strong resi stance genes than their male counterparts, as well as being incompletely dominant (Wang et al. 2006). 35

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Avermectins While avermectins were touched on earlier, here the mode of action is explored more in depth. Additionally, the development of averm ectins, especially emamectin benzoate is discussed. Mode of Action All avermectins have the same mode of ac tion (Campbell et al. 1983, Dybas et al. 1989). Originally, avermectins were thought to work on the central nervous system; affecting chloride channels by stimulating the release of the ne urotransmitter GABA from the presynaptic neuron and enhancing its binding to the postsynaptic membrane. This enhanced binding does not increase the duration that GABA is bound to the s ite, but rather increases the number of sites available to GABA (Pong et al 1980, Pong and Wang 1982, Turn er and Schaeffer 1989). GABA is a neural inhibitor and its bind ing causes an influx of chloride ions into the neuron. This influx acts to dampen neural excitation. The primary mode of action for avermectins is as an agonist in the peripheral nervous system (Jansson and Dybas 1998, Buckingham 2005). At neuromuscular junctions, avermectin binds to the postsynaptic membrane, which again allows for the influx of chloride ions. These dampening effects in the central and peripheral nervous systems result in neuron-inhibition and flaccid paralysis (Campbell et al. 1983, Zufall et al. 1988, Turner and Schaeffer 1989, Yu 2007). Development Avermectins are a class of membered m acrocyclic lactone ring insecticides that affect chloride channels. Their initial developm ent came about when scientists at Merck Sharp & Dohme Research Laboratories were looking for microbial fermentation products with anthelmintic activity. An actinomycete ( Streptomyces avermitilis ), which was originally isolated 36

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at the Kitasato Institute in Ja pan from a soil sample, produced tw o series of co mpounds, A and B (Campbell et al. 1983). Ultimately, four homol ogous pairs (eight compounds) which could be subdivided into major (A 1a A 2a B 1a B 2a ) and minor (A 1b A 2b B 1b B 2b ) groups were developed (Burg et al. 1979, Campbell et al. 1983, Fisher and Mrozik 1989). Avermectins, generally, consist of a mixture of a major and a minor group ( 80% to 20% respectively), due to the prohibitive cost of isolating individual groups and because the two groups have similar biological activities (Dybas et al. 1989, Fisher and Mrozik 1989, Jansson and Dybas 1998). From these compounds, ivermectin was pure and m arketed as an antiparasitic in 1981. In 1985, abamectin became available to control agricu ltural pests (Campbell 1989). By the mid 1990s abamectin was available for cockroach control (Appel and Benson 1995). Further experimentation in 1984 resulted in th e discovery of emam ectin benzoate. Emamectin Benzoate Emamectin benzoate was first registered in 1999 for use in field crops to control lepidopteran pests (Leibee et al. 1995, Jansson et al. 1996, Jansson et al. 1997, Ishaaya et al. 2002). As a soluble granule, it is sprayed on crops where, initially, it ha s some contact activity (Chukwudebe et al. 1997). However, emamectin be nzoates translaminar, non-systemic activity allows it to form a reservoir within treated leaves. It is in this state that it is most effective and emamectin is reported to be several hundred fo ld better at controlli ng lepidopteran crop pests than abamectin (Fisher 1993). Insect pests c onsume not only plant material but also the emamectin benzoate, which results in paralysi s and death in 3-4 d (S yngenta 2007). Emamectin benzoate has use in aquacu lture to control sea lice ( Lepeophtheirus salmonis and Caligus elongatus ) which are parasites of salmon and trout in fish farms (Stone et al. 1999). In this application, the fish are fed the emamectin benzoa te in a feed mixture such as Slice. The sea 37

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lice acquire emamectin benzoate when parasitizing th e fish. Once in the sea lice it binds to ion channels of nerve cells and disrupts transmission of nerve impulses (Schering-Plough 2007). Research testing emamectin benzoate in pi ne trees has also been conducted. A liquid formulation was developed for injection into pi ne trees to control th e pine wood nematode, Bursaphelenchus xylophilus and found to have a residual effect for at least 3 years (Takai et al. 2000, 2001, Takai et al. 2003, 2004). Additional experi ments testing emamectin benzoate for control of the southern pine engraver beetle and wood borers in Loblolly pines has also been performed (Grosman and Upton 2006). In these e xperiments, pine trees were injected with emamectin benzoate. Trees were observed for up to 5 months for the presence of egg galleries and attacks by beetles. They found that emamectin benzoate controlled bo th egg galleries and attacks, but caused vertical le sions at each injection point. Whether it is biochemical or behavioral, re sistance is the reason new insecticides and improved formulations, especially gel baits, need to be developed. Gel ba its are heavily relied upon in the pest control industry fo r their low exposure of humans to insecticides, the ability to target cockroaches where they live and their abilit y to be used in sensitiv e areas. Therefore, in this study, I tested at an experimental gel bait ma trix with the avermectin insecticide, emamectin benzoate, which has not been us ed for cockroach control. 38

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CHAPTER 3 EMAMECTIN BENZOATE ON ORLANDO AND DAYTONA STRAINS OF GERMAN COCKROACH Introduction Insects are highly adaptable creatures, able to survive everything from arid deserts to frozen mountaintops. Consequently, some of them are able to survive the various insecticides used to control them. The German cockroach, Blattella germanica L., is no exception. According to Whalon et al. (2007), the German cockroach is resistant to 42 active ingr edients. Some factors that aid in development of insecticide resist ance are high reproductive rate, low migration, and high selection pressure, which is re peated exposure to the same insecticide or class of insecticide. Not surprisingly, the German cockroach benefits from all of those factors. It takes as little as two years (6-8 generations) for German cockroaches to develop resistance under high selection pressure (Cochran 1995). Using la boratory selection strategy, Scharf et al. (1998) identified a high-level resistance evolution in three generations. There ar e three major categories of resistance (Georghiou 1972): physiologi cal, biochemical and behavioral. Physiological and biochemical resistance, to an insecticide, occur when an insect is able to survive a level of exposure that is normally lethal and which results in control failures. Because of genetic variability, all populations have some level of resistance; it is believed that the levels are low. However, those levels can increase quickly when sele ction pressure is high. Mechanisms of resistance in clude decreased pene tration through the cuticle, target-site insensitivity, and increas ed enzyme production, in which deto xification enzymes detoxify the insecticide thus making it less toxic and easie r to excrete from the body (Cochran 1995). One example of this sort of resistance in German co ckroaches is pyrethroid resistance in which strains can exhibit increases in enzyme activity and/or target site insensitiv ity (Umeda et al. 1988, Scharf et al. 1998). 39

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Behavioral resistance occurs when an insect is able to avoid an insecticide due to an increased ability to detect the insecticide or a change in pref erence. As with physiological and behavioral resistance, behavioral resistance can also result in s ubstantial control failures. This type of resistance occurred in some strains of the German cockroach in the early 1990s. German cockroaches developed an aversion, or change in preference, to c onsuming gel baits with glucose (Silverman and Bieman 1993). Gel bait manufactures were able to overcome this resistance by substituting glucose with othe r sugars. However, less than a decade, later bait aversion reappeared in a few strains of German cockroaches that were controlled, almost exclusively, with gel baits (Morrison et al. 2004, Kramer and Miller 2004). These new strains of bait averse German cockroaches had developed an aversion to a numerous sugars and possibly other inert bait matrix ingredients (Wang et al. 2004). Due to the resistance of German cockroaches, it is important to develop new products to combat them. Emamectin benzoate has been in use against lepidopteran crop pests, and sea lice on salmon. Emamectin benzoate is a novel insecticide for cockroach control. It is in the same class of insecticides, avermectin s, as abamectin; however, there is some evidence that emamectin benzoate may have inherently better insectic idal properties than abamectin. Emamectin is several hundred fold better at controlling lepidopteran pests than abamectin (Fisher 1993). However, further research will be required to de termine if emamectin benzoate is more toxic to cockroaches than abamectin. My objective for this study was to determine if cockroach gel baits containing emamectin benzoate would be palatable to both a susceptibl e and bait averse strain of German cockroaches. I also wanted to determine if bot h, the susceptible and bait averse strains were susceptible to gel baits containing emamectin benzoate. 40

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Materials and Methods Insecticides Four experimental formulated emamectin benz oate gel baits, a blank gel bait base and a standard gel bait were tested. Th e experimental emamectin benzoate gel baits were formulated as either emamectin A or emamectin B at ei ther 500 or 1000 ppm (Syngenta Crop Protection, Greensboro, NC). The blank gel bait base cont ained no active ingredient The current industry standard gel bait utilized in this study was Maxforce FC Sel ect with 0.01% (100 ppm) of the active ingredient fipronil (Bayer Envi ronmental Science, Montvale, NJ). Insects Orlando (non-bait averse) and Daytona (bait av erse) strains of German cockroaches were reared at the University of Flor ida, urban entomology laboratory (G ainesville, FL) in glass utility jars (25.5 high x 22.0 diameter cm) with the inner top 5 cm greased with a petroleum jelly/mineral oil mixture (2:3) to prevent cock roach escape. Each jar contained cardboard for harborage and was provided water and dry food ad libitum The Orlando strain was fed rodent food (Labdiet 5001, PMI Nutrition Int., Brentw ood, MO) and the Daytona strain was fed dog food (Purina One puppy: growth and development, Nestl PetCare Company, St. Louis, MO.) due to aversion to rodent food. The cockroaches were maintained at 23.6 2.5C at 51 16% RH at a photoperiod of 12:12 (L:D). For test ing, cockroach nymphs were separated from colonies by anaesthetization with carbon dioxide for less than 5 min, and then sifted using #8 (2.36 mm) and #10 (2.00 mm) testing sieves. Sec ond and third instar nymphs, passing through the #8 sieve and retained in the #10 sieve, were pl aced in jars with rodent diet or dog food, water, and harborage. All nymphs were allowed to rec over for 48 h to recover from anaesthetization prior to utilization in tests. Co ckroaches not used in this stud y were returned to colonies. 41

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Assay Setup The test arenas were lidded transparent plas tic boxes (27 x 19.5 x 9.5 height cm) with the inner top 5 cm greased with a petroleum jelly/m ineral oil mixture (2:3) to prevent cockroach nymph escape. The arena containe d harborage [a blank white i ndex card (7.6 x 12.7 cm) folded lengthwise and stapled] and a water vial with a cotton stopper. Cockroach nymphs (50) were aspirated from the holding jar, collected in a 50 ml tube, and placed into a test arena. After placement into arenas, cockroach nymphs were starved for 24 h, at which time dead cockroach nymphs and exuviae were removed. Assay Method Cockroach nymphs were provided a choice between pre-weighed dog food (~0.28 g) or gel bait (~0.21 g) which were placed on pieces of paper (3.8 x 3.8 cm Fisherbrand weighing paper). In control assays, dog food replaced ge l baits and, therefore, received dog food only. Similar amounts of dog food or gel bait were plac ed into 30 ml cups, which were then covered with an organdy fabric square and held in pl ace with a rubber band to prevent cockroach access. These moisture controls were used to adjust for loss/gain in consumpti on calculations. The four portions, two dog foods and two gel baits, were pl aced in test arenas simultaneously. After 24 h, the four portions were reweighed. The dog food and ge l bait were placed b ack into the arena for the remainder of the study. Cockroach nymph mort ality was recorded 6 d after the introduction of food. Mortality was defined as cockroach nymph inability to self-right. Data Analysis Consumption was calculated as follows: Consumption = B B {B B x [(MC B MC A ) / MC B ]} B A 42

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where B B is the pre-weight of dog food/gel bait before introduction into the arena, MC B is the pre-weight of moisture control food/gel bait, MC A is the post-weight of moisture control food/gel bait 24 h after introduction into the arena, and B A it the post-weight of exposed food/gel bait (Ncherne 2006). Each portion was weighed indi vidually before introduction into the testing arena and 24 h later. Percent gel bait consumption was calculated as follows: Percent consumption = [GB / (GB + DF)] x100 where GB is gel bait consumed (mg) a nd DF is dog food consumed (mg) (Ross 1998). Consumption and mortality data were arcsine square root transformed before being analyzed by analysis of variance (ANOVA) with means separa ted by the Student Newman Keuls (SNK) test or the Students t -test ( = 0.05; SAS Institute 2003). Results Consumption Soon after introduction of the ge l baits and/or dog food to th e test arenas, cockroaches were observed consuming gel baits and dog food. Between strains, there was no significant difference in percent consumption for dog food or any of the gel baits (b ait base, Maxforce FC Select, emamectin A, and emamectin B). Between strains and within each strain, there was no significant difference in percen t consumption of emamectin A and emamectin B gel baits. For the Orlando strain, there was no significant difference in percent consumption of any of the gel bait or dog food ( F = 1.56, df = 6, P = 0.1739) (Table 3-1). For the Daytona strain, the dog food had the lowest percent consumption an d was significantly difference from Maxforce FC Select and bait base ( F = 3.74, df = 6, P = 0.0030). However, there no significant difference in percent consumption between any of the gel baits (emamectin A, emamectin B, Maxforce FC Select, or bait base). 43

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Mortality After the initial introduction of gel baits and dog food, mortality was observed in as little as 24 h. Between strains, Orlando strain had signi ficantly higher percent mortality than Daytona strain for dog food and bait base treatments (Table 3-2). There was no significant difference in percent mortality for emamectin A, emamectin B or Maxforce FC Select between strains. Additionally, between strains and within each st rain, there was no significant difference in percent mortality of emamectin A and emamectin B gel baits. Within strains, for both Orlando and Daytona, there was no significant difference in percent mortality for dog food and bait base ( F = 234.96, df = 6, P <0.0001 and F = 593.31, df = 6, P <0.0001, respectively). Maxforce FC Select was significantly different from emamectin A, emamectin B, bait base, and dog food, which had lo wer percent mortalities. The bait base and dog food had the lowest percent mortality and we re significantly differe nt from Maxforce FC Select, emamectin A and emamectin B. There wa s no significant difference in percent mortality between emamectin A and emamectin B. For both the Orlando and Daytona strains (Fi g. 3-1 and 3-2 respectively), emamectin A and B 1000 ppm had slightly faster speed of action than the emam ectin A and B 500 ppm, at 3 d. However, for emamectin A and B at 500 and 1000 pp m, there were no significant differences at 6 d. Discussion German cockroaches are highly adaptable crea tures, and for this reason, new products to control them need to be developed and tested. Pr evious studies have confirmed the existence of bait averse German cockroaches (Wang et al 2004, 2006, Ncherne 2006). In those studies bait averse and normal strains were tested. Wang et al. (2006) tested second generation blank gel 44

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baits (Avert with abamectin and Maxforce FC w ith fipronil) and Nchern e (2006) tested first, second generation (Maxforce FC and Avert) and third generation cockroach gel baits (Maxforce FC Select). Second generation cockroach gel ba its were developed in response to glucose aversion and third generation cockroach gel baits were developed in response to the more recent bait aversion. All of these studies found that bait averse strain s ate significantly less first and second generation gel baits than the normal suscep tible strains. In my study, the Daytona strain consumed a larger percentage of gel bait than the Orlando strain. This was similar to Nchernes (2006) study with third generation gel baits, in which the Daytona strain consumed greater amounts than the Orlando strain. Using abamectin gel baits, Cochran (1994) te sted 13 strains of fi fth and sixth instar German cockroaches and observed a wide range of susceptibility, 31.1% to 97.8% mortality. Also using abamectin gel baits, Negus and Ross (1997) compared six strains of sixth instar German cockroaches and found the susceptibility of two of the six strain s to be significantly different from each other. In my study, percent mo rtality across strains wa s similar for each of the formulated emamectin benzoate gel baits a nd Maxforce FC Select at 6 d. The length of the test in Negus and Rosss experime nt, which only ran for 3 d, may not have been of an adequate duration. Ross (1993) observed that large nymph s did not reach 80% mortality until after 5 d, when fed abamectin. Fipronil kills a greater percentage of Ge rman cockroaches compared to abamectin (Durier and Rivault 2000, Wang et al. 2004, 2006, Nc herne 2006). The toxic effect of fipronil occurs faster than the effect of abamectin (Gahlhoff et al. 1999, Durier and Rivault 2000, Stejskal et al. 2004). I found similar results in this study. Maxforce FC Select had the greatest percent mortality for both strains at 6 d. Howeve r, 100% mortality was observed at 13 d for mid45

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instar nymphs when given a choice between dog food and abamectin gel bait (Ross 1993). This suggests that while emamectin benzoate could have a slower speed of action compared to fipronil, total mortality may be comparable if given adequate time. Fipronils faster speed of action may also affect its horizontal kill. In my experiment, fipronil arenas were observed to be relatively free of feces compared to all other arenas. The eating of feces, especially by early instar nymphs, is one type of horizontal kill. Feces appeared to play a minor role in the transfer of fipronil for German cockroaches (B uczkowski and Schal 2001). This is could be due to its fast speed of action, about 4 h (Durier and Rivault 2000), which may not give the German cockroach time to defecate prior to mortality. This possibility, as well as other modes of horizontal transfer and mortality should be further investigated. As was expected, emamectin A and B at 1000 ppm, for both the Orlando and Daytona strains, had slightly higher morality at 3 d, compared to emamectin A and B at 500 ppm. I would expect a gel bait with a higher concentration of ins ecticide to work slightly faster than one with a lower concentration. However, there was no signif icant difference between any of the emamectin gel baits, A and B at 500 and 1000 ppm, at 14 d. The Orlando strain showed grea ter susceptibility than the Daytona strain, even though the Daytona strain had higher consumption rates. Th is could indicate some physiological and /or biochemical resistance to emamectin benzoate in the Daytona strain. However, Orlando also had higher percent morality for the control and bait base, so the higher mortality percentage may be due to natural mortality rather than to resistance. In conclusion, my study has shown that novel bait base, emamectin A and emamectin B were able to over come putative feeding deterrence in a bait averse strain of German cockroach, and were, essentially, equally pala table to both normal and bait av erse strains. This study also 46

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showed that when German cockroaches consumed the gel baits with emamectin benzoate, a high level of mortality was obtained at 6 d. Howeve r, emamectin benzoate has a slower speed of action than fipronil, which probably effects fipr onils horizontal transmission. A longer study, of at least 13 d, is needed to compare accurately the mortality between fipronil and emamectin gel baits. 47

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Table 3-1. Gel bait preference by Blattella germanica nymphs (Orlando and Daytona strains) in a 24 h choice experiment. Bait as percent of total consumption (Mean sem) a Strain Students t-test (P = 0.05) Treatment Orlando Daytona df t-value P-value Dog Food 50.9 6.42a 51. 2 4.09b 18 0.04 0.9694 Bait Base 67.7 3.44a 75.3 2.06a 18 1.90 0.0742 Maxforce FC Select 68.3 4. 73a 74.0 3.14a 18 0.99 0.3370 Emamectin A 1000 ppm 59.6 4.03a 62.3 3.37ab 18 0.51 0.6182 Emamectin A 500 ppm 60.5 3.32a 64.6 4.12ab 18 0.78 0.4468 Emamectin B 1000 ppm 61.6 5.90a 63.2 5.55ab 18 0.20 0.8457 Emamectin B 500 ppm 61.9 3.77a 63.4 5.63ab 18 0.23 0.8195 a Consumed percentage was obtai ned by the following formula: {gel bait consumed (mg) / [gel bait consum ed (mg) + dog food consumed (mg)]} x 100. Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 48

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Table 3-2. Mortality at 6 d after bait placement of Blattella germanica nymphs (Orlando and Daytona strains). Pe y rcent Mortalit S 0.05) a e e train Students t -test ( P = Treatment Orlando Dayton df t -valu P -valu Dog Foo d c c 4.7 0.95 0.4 0.44 11.4 -4.06 0.0018 Bait Bas e c c elect a a ppm b b ppm b b ppm b b ppm b b 7.4 2.16 1.1 0.48 8.8 -2.85 0.0116 Maxforce FC S 99.8 0.22 99.1 0.49 11.1 -1.26 0.2342 Emamectin A 1000 90.3 1.70 86.8 1.30 14.9 -1.67 0.1163 Emamectin A 500 86.4 5.39 81.6 2.46 11.2 -0.81 0.4322 Emamectin B 1000 88.5 2.34 88.0 2.98 16 -0.12 0.9048 Emamectin B 500 87.4 2.87 86.5 2.14 14.8 -0.26 0.7990 Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 49

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0 20 40 60 80 100 01234567 Days P ercen t M or t a lit y Emamectin A 500 ppm Emamectin A 1000 ppm Emamcetin B 500 ppm Emamectin B 1000 ppm Figure 3-1. Percent mortality at 3 and 6 d after bait placement for the Orlando strain of Blattella germanica nymphs. 50

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0 20 40 60 80 100 01234567 DaysPercent Mortalit y Emamcetin B 500 ppm Emamectin B 1000 ppm Emamectin A 500 ppm Emamectin A 1000 ppm Figure 3-2. Percent Mortality at 3 and 6 d after bait placement for the Daytona strain of Blattella germanica nymphs. 51

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CHAPTER 4 EMAMECTIN BENZOATE ON DOMESTIC COCKROACHES Introduction Domestic cockroaches, which live and br eed almost exclusively indoors, like brownbanded cockroaches, Supella longipalpa (Serville) and German cockroaches, Blattella germanica L., can be found throughout the United St ates. These domestic cockroaches have a close association with humans, leading some to believe that there may be co-evolution between domestic cockroaches and humans (Barcay 2004). Because of how closely associated they are with humans, they are considered pests for aesthetic and health reasons. Aside from producing foul smelling odors, they are capable of produci ng allergens, which can elicit asthma attacks (Rosenstreich et al.1997). They have been impli cated as disease vectors, being carriers of a number of bacterial, viral, a nd fungal pathogens, including salmone lla, hepatitis, and e-coli (Roth and Willis 1957, Le Guyader et al. 1989). For these reasons, control of cockroaches is essential. When controlling cockroaches, harborage locati on is important. While it is possible to find both the German cockroach and the brownbande d cockroach in the same structure and even the same harborage (Barcay 2004), they tend to inhabit very different areas. The German cockroach is commonly associated with kitche ns and bathrooms, where their preference for warm, humid areas with low airflow, and daily access to water can be satisfied. Brownbanded cockroaches also prefer warm areas, but they do not require daily acce ss to water. For this reason, they are able to survive in drier areas of structures. Brownbanded cockroaches are also called the furniture cockroach in some parts of th e world, because they have a tendency to reside in furniture of all types. They can also be found under shelves, behind pictures and inside electronics (Pinto 1988). 52

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Once infestations are established, control measur es need to be taken. However, resistance can complicate cockroach control. While brownba nded cockroaches are susceptible to a variety of insecticides (Burden 1980, Koeh ler et al. 1991, Pospischil et al. 1999) and is not known to be resistant to any insec ticides (English 2003), deve lopment of resistance is always a possibility. German cockroaches are resistant to a large num ber of insecticides (Whalon et al. 2007) and some strains have even developed an aversi on to gel baits (Silverman and Bieman 1993, Silverman and Ross 1994, Wang et al. 2006, Ncherne 2006). Cockroach gel bait aversion is especially troubling as gel bait use has become a major pest control technique (Stejska and Aulicky 2006). Gel baits have the benefit of decr easing the amount of insecticide placed in the environment and reducing human and pet exposure to insecticides. It can also be used in sensitive areas, such as hospitals and restaurants. Because insecticide resistance is generally c onsidered inevitable, it is important to develop and test new insecticides for cockroach c ontrol. Emamectin benzoate is currently used to control sea lice on salmon (Stone et al. 1999) as well as to control lepido pteran pests in field crops. Emamectin benzoate is a novel insectic ide that is being deve loped for control of cockroaches. It is in the same class of insecticid es, avermectins, as abamectin. However, there is some evidence that emamectin benzoate may have inherently better insecticidal properties than abamectin (Dybas et al. 1989). Emamectin is repor ted to be several hun dred fold better at controlling lepidopteran pests than abamectin (F isher 1993). However, further research will be required to determine if emamectin benzoate is more toxic to cockroaches than abamectin. The objective of my study was to determine if cockroach gel baits containing emamectin benzoate would be palatable to the brownbanded cockroach as well as to the bait averse Daytona 53

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strain of German cockroach nymphs. Additionally, I wanted to determine if gel baits formulated with emamectin benzoate were capable of controlling both species cockroaches. Materials and Methods Insecticides Five experimental formulated emamectin be nzoate gel baits, and one standard gel bait were tested. The experimental emamectin benz oate gel baits were formulated as either emamectin A at a concentration of 0.1% or emamectin B at a concentration of 0.05%, 0.1%, or 0.2%. One of the formulated gel baits contained no active ingredient (Sy ngenta Crop Protection, Greensboro, NC). The current indus try standard gel bait utilized in this study was Maxforce FC Select with 0.01% of the active ingredient fipron il (Bayer Environmental Science, Montvale, NJ). Insects Daytona strain (bait averse) German co ckroaches (Ncherne 2006) and brownbanded cockroaches were reared at the University of Florida, urban entomology laboratory (Gainesville, FL) in glass utility jars (25.5 high x 22.0 cm diam eter) with the inner top 5 cm greased with a petroleum jelly/mineral oil mixture (2:3) to pr event escape. Each jar contained cardboard for harborage, and was provided water and dry food ad libitum Brownbanded cockroaches were fed rodent food (Labdiet 5001, PMI Nutrition Int ., Brentwood, MO) and German cockroaches were fed dog food (Purina One puppy: growth and development, Nestl PetCare Company, St. Louis, MO.) due to aversion to rodent food. Th e cockroaches were maintained at 23.6 2.5C at 51 16% RH at a photoperiod of 12:12 (L:D). For testing, German cockroach nymphs were separated from the colony by anaesthetization for less than 5 min with carbon dioxide and then sifted, using #8 (2.36 mm) and #10 (2.00 mm) testi ng sieves. Second and third instar German 54

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cockroach nymphs, passing through the #8 sieve and retained in the #10 sieve, were placed in jars with rodent food, water, and harborage for 48 h to recover from anaesthetization prior to test. All other cockroaches were returned to th e colony. Mixed populat ions of brownbanded cockroaches (10 adult males, 10 adult females, and 30 nymphs, third to fifth instars) were removed from the colony with feather tip forceps. Assay Setup The test arenas were lidded transparent plas tic boxes (27 x 19.5 x 9.5 cm height), with the inner top 5 cm greased to prevent cockroach es cape. The arena containe d harborage [a blank white index card (7.6 x 12.7 cm) folded lengthwise and stapled] and a wate r vial with a cotton stopper. Fifty German cockroach nymphs or 50 br ownbanded cockroaches were placed into test arenas and starved for 24 h. Dead cockroaches and exuviae were removed prior to introduction of dog food and gel baits. Assay Method German cockroach nymphs and brownbanded cockroaches were provided a choice between pre-weighed dog food (~0.28 g) or gel bait (~0.50 g) which were placed on pieces of paper (3.8 x 3.8 cm, Fisherbrand weighing paper). In control assays, dog food replaced gel baits and, therefore, received dog f ood only. Similar amounts of dog food or gel bait were placed into 30 ml cups, which were then covered with an or gandy fabric square and held in place with a rubber band to prevent cockroach access. The covered dog food or gel bait was used for moisture controls to adjust for loss/gain in consump tion calculations. The four portions, two dog food and two gel bait, were placed in arenas simultaneously. After 24 h, the four portions were reweighed. The dog food and gel bait were placed back into the arena for the remainder of the study. 55

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Cockroach mortality was recorded up to 14 d af ter the introduction of dog food and gel bait. Mortality was defined as the cockroach nymphs inability to self-right. Data Analysis Consumption was calculated as follows: Consumption = B B {B B x [(MC B MC A ) / MC B ]} B A where B B is the pre-weight of dog food/gel bait before introduction into the arena, MC B is the pre-weight of moisture control food/gel bait, MC A is the post-weight of moisture control food/gel bait 24 h after introduction into the arena, and B A it the post-weight of exposed food/gel bait (Ncherne 2006). Each portion was weighed indi vidually before introduction into the testing arena and 24 h later. Percent gel bait consumption was calculated as follows: Percent consumption = [GB / (GB + DF)] x100 where GB is gel bait consumed (mg) a nd DF is dog food consumed (mg) (Ross 1998). Consumption and mortality data were arcsine square root transformed before being analyzed by analysis of variance (ANOVA) with means separa ted by the Student Newman Keuls (SNK) test or the Students t -test ( = 0.05; SAS Institute 2003). Linear regression analysis was performed with consumption as the depende nt variable and concentration of emamectin benzoate as the independent variable for brownbanded cockroaches (SAS Institute 2003). Results Consumption Both brownbanded cockroaches and German cockroach nymphs, within about 5 min of introduction, could be seen around both the gel bait and dog food. Brownbanded cockroaches and Daytona cockroach nymphs did not show a preference to either pi ece of dog food in the control arenas, indicat ing that there was not a bias for food location (Table 4-1). 56

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For brownbanded cockroaches, there was no significant difference in consumption between any of the gel baits or dog food ( F = 0.33, df = 6, P = 0.9151). However, at the higher concentrations of emamectin benzoate, there wa s an increase in percen t consumption. Regression of consumption versus emamectin benzoate co ncentration was highly correlated with an R 2 of 0.9875 (Fig. 4-3). For Daytona cockroach nymphs, dog food had the lowest percent consumption and was significantly difference from the gel baits (emamectin A 0.1%, emamectin B 0.2%, 0.1%, and 0.05%, bait base and Maxforce FC Select) ( F = 9.85, df = 6, P <0.0001). There was no significant difference in consumpti on between any of the gel baits. For German cockroach nymphs and brownba nded cockroaches, there was no significant difference in percent consumption between emamectin A 0.1% and the emamectin B 0.05%, 0.1%, and 0.2%. Therefore, the inert ingredients in emamectin A do not act as feeding deterrents or stimulants. Mortality For Daytona cockroach nymphs and brownbanded cockroaches, mortality was observed within the first 24 h. For both brownbanded cock roaches and Daytona strain nymphs, there was no significant difference in perc ent mortality between the bait ba se and dog food (Table 4-2). The bait base contained no active in gredient; therefore, mortality was expected to be similar to dog food. For Daytona cockroach nymphs a nd brownbanded cockroaches, there was no significant difference in percen t mortality between Maxforce FC Select, emamectin A 0.1%, or emamectin B 0.05%, 0.1%, and 0.2%) ( F = 226.66, df = 6, P <0.0001 and F = 149.77, df = 6, P <0.0001, respectively). 57

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For brownbanded cockroaches, emamectin B 0. 2% had the fastest speed of action among the emamectin gel baits, with 50% mortality at ~2 d and 90% mortality at ~5 d (Fig. 4-1). Emamectin A at 0.1% and emamectin B at 0.1% had similar speeds of action with 50% mortality also at ~2 d and 90% mortality in about 6 to 8 d. Emamectin B 0.05% had the slowest speed of action through 14 d, with 50% mortality in 2 to 3 d and 90% mortality in ~9 d. For the bait averse German cockroaches, emamectin benzoate gel baits all had similar speeds of action initially with 50% mortality at ~2 d (Fig. 4-2). However, 90% mortality for Emamectin A 0.1% and emamectin B 0.1% and 0.05% was ~7 d and for emamectin B 0.2% 90% mortality was at ~11 d. Discussion Daytona cockroach nymphs consumed greate r percentage of gel baits than dog food. Most information on bait averse German cockroach strains pertains to bait failures due to sugar aversion (Silverman and Bieman 1993, Wang et al. 2004). However, one study found that the Daytona (bait averse) strain of German cock roaches consumed more dog food than first generation (Maxforce ) or second generation (Avert and Maxforce FC) cockroach gel baits (Ncherne 2006). Conversely, the study also f ound that third generation cockroach gel baits (Maxforce FC Select and Advion ) were consumed more than dog food. Similarly, in my study, I found that the Daytona strain consumed more Maxforce FC Select, bait base, emamectin A and emamectin B gel baits than dog food. Brownbanded cockroaches consumed about an equal percentage gel baits and dog food. While there is limited information on consumption for brownbanded cockroaches, Cohen et al. (1987) were able to determine that brownbanded cockroaches would self-select protein at 15.5% and glucose at 84.5%. When given a single diet cube at 20:80 (p rotein: glucose) nymphal growth 58

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was stunted and with single diets of 0: 100 or 100: 0 (protein: glucose), there was little consumption. However, when give a choice between two cubes with nutritionally complete diets, with equal amounts of protein and glucose (50: 50), brownbanded cockroaches consumed about equally from both cubes. In my study, brownbande d cockroaches consumed similar percentages of dog food, which has a crude protein ratio of 28.0% (Purina One 2007), and gel baits: bait base, Maxforce FC Select, emamectin A, and emamectin B. This suggests that all the gel baits and dog food were nutritionally equal fo r brownbanded cockroaches. Avermectin at high concentrations is a feed ing inhibitor (Cochran 1985). However, in my study, there was a good correlation between consum ption and concentrations of emamectin benzoate for brownbanded cockroaches. With an increasing concentration of emamectin benzoate, consumption increased (F ig. 4-3). This is may indicate that emamectin benzoate is a feeding stimulus for this species. However, furt her research into the feeding preferences is required for the brownbanded cockroach. Brownbanded cockroaches are highly suscepti ble to emamectin benzoate. Tests with various insecticides on brownbanded cockroach es show good efficacy (Whitney et al. 1967, Burden 1980, Pospischil et al. 1999). Similarl y, in my study, high percent mortalities ( 96%) were observed for all formulated gel baits. The Daytona (bait averse) strain German cock roach is susceptible to emamectin gel baits, which are in the same class of insecticide as abamectin. Using abamectin gel baits, Cochran (1994) tested 13 strains of 5 th to 6 th instar German cockroaches and observed a wide range of susceptibility levels from, 97.8 to 31.1%. Also us ing abamectin gel baits, Negus and Ross (1997) compared six strains of sixth instar German cock roaches and observed suscep tibility levels in of two of the six strains to be significantly different from each other. Abamectin gel baits were used 59

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on mid-sized nymphs; 100% mortality was obser ved after 14 d (Ross 1993). Similar to Rosss findings, for the Daytona strain, I observed between 95% and 99% mortality 14 d after introduction of emamectin A, emamectin B or Ma xforce FC Select gel ba its. The length of the test in Negus and Rosss experime nt, which only ran for 3 d, may not have been of an adequate duration. Additionally, in the Cochran (1994) study and the Negus and Ross (1997) study, unidentified bait averse strains could explain the observed mortality in the different strains. High levels of susceptibility have been observed in brownbanded cockroaches when exposed to insecticides, often within 3 d af ter treatment (Whitney et al. 1967, Burden 1980, Pospischil et al. 1999). The LT 50 for abamectin at 0.0550% on brownbanded cockroaches was observed to be 4.54 d (Koehler et al. 1991). Likewise, in my study, by 2 d, emamectin A 0.1% and emamectin B 0.1% and 0.2% had ~50% mortality (Fig. 4-1). Emamectin B 0.05% had 50% mortality at ~3 d. By 14 d, all emamectin gel baits had 96% to 99.5% mortality. The German cockroach is susceptible to emamec tin benzoate, possible at similar or better levels as abamectin. The LT 50 for German cockroaches at 0.0500 and 0.100% abamectin was observed to be 1.550 and 2.067 d, respectively (Koe hler et al. 1991). Likewise, in my study, emamectin A 0.1%, emamectin B 0.05%, 0.1%, and 0.2% mortality was between 40% and 60% at 2 d (Fig. 4-2). At 7 d, emamectin gel bait, A and B at 0.05% and 0.1%, mortalities were greater than 90%. At 14 d, all emamectin gel baits had 95.7% to 99.4% mortality. In conclusion, my study gel baits with a novel insecticide, emamectin benzoate, palatable to both brownbanded cockroaches and Daytona strain (bait averse) German cockroaches. Additionally, I observed that emamectin benzoate consumed by Daytona strain German cockroaches and brownbanded cockroaches whic h resulted in high susceptibility. The high 60

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susceptibility and palatability make emamectin benzoate gel baits ex cellent candidates for controlling domestic cockroaches. 61

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Table 4-1. Gel bait preference by Supella longipalpa mixed population, and Blattella germanica nymphs (bait averse Daytona strain) in a 24 h choice experiment. Bait as percent of total consumption (Mean sem) a Treatment Supella longipalpa (n=4) Blattella germanica (Daytona strain) (n=9) Dog Food 52.7 4.19a 48.5 5.64b Blank Bait Base 50.4 11.07a 78.8 2.76a Maxforce FC Select 61.2 10.47a 79.0 4.87a Emamectin A 0.1% 62.6 11.07a 81.7 2.32a Emamectin B 0.05% 56.0 12.72a 84.5 2.99a Emamectin B 0.1% 58.4 10.96a 85.0 1.89a Emamectin B 0.2% 66.7 9.63a 78.4 3.24a a Consumed percentage was obtai ned by the following formula: {gel bait consumed (mg) / [gel bait consum ed (mg) + dog food consumed (mg)]} x 100. Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 62

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Table 4-2. Percent mortality of Supella longipalpa mixed population, and Blattella germanica nymphs (bait averse Daytona st rain) 14 d after bait introduction. Pe y rcent Mortalit Treatment Supella longipalpa (n=4) n=9) Blattella germanica (Daytona strain) ( Dog Food 7.5 1.26b 3.43 0.72b Blank Bait Base 9.5 3.59b 3.43 1.04b Maxforce FC Select 100 0.00a 96.6 2.17a Emamectin A 0.1% 99.5 0.50a 97.1 1.38a Emamectin B 0.05% 96.0 2.31a 99.4 0.37a Emamectin B 0.1% 98.0 1.15a 97.1 1.56a Emamectin B 0.2% 99.5 0.50a 95.7 1.11a Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 63

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0 20 40 60 80 100 02468101214Time in DaysPercent Mortality 16 Emamectin A 0.1% Emamectin B 0.05% Emamectin B 0.1% Emamectin B 0.2% Figure 4-1. Percent mortality for Supella longipalpa at 3, 6, 8 and 14 d after introduction of emamectin gel baits. 64

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0 20 40 60 80 100 02468101214Time in DaysPercent Mortality 16 Emamectin A 0.1% Emamectin B 0.05% Emamectin B 0.1% Emamectin B 0.2% Figure 4-2. Percent mortality for Blattella germanica nymphs (bait averse Daytona strain) at 2, 4, 7 and 14 d after introduction of emamectin gel baits. 65

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y = 78.8x + 50.98 R2 = 0.9875 0.0 20.0 40.0 60.0 80.0 00.050.10.150.20.25 Concentration of Emamectin benzoatePercent Consumption Figure 4-3. Percent consumption for Supella longipalpa cockroach, at increasing concentrations of emamectin benzoate. 66

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CHAPTER 5 EMAMECTIN BENZOATE ON PERIDOMESTIC COCKROACHES Introduction Of the more than 4,000 described species of cockroaches, only 69 inhabit North America (Bell 1984, Atkinson et al. 1991, Ma bbett 2004) and of those, only about 25% are found living in close association with humans (Barcay 2004 ). The majority of these cockroaches are considered peridomestic, living and breeding outd oors near human structures and occasionally entering and infesting structures, or feral, living and breeding out doors away from human activity and rarely encountering humans. Of the peridomestic cockroaches, both the American and Oriental cockroach are considered pests. Their pe st status is due in part to their tendency to move indoors, as well as, their ability to transmit pathogens. The most common peridomestic cockroach is the American, Periplaneta americana L., which is distributed widely throughout the United States, living mostly outdoors in tropical and subtropical regions and movi ng indoors in more temperate regions (Bell 1984). American cockroaches prefer warm, humid, damp areas, and are closely associated with sewers. Outdoors, they can also be found under leaf debris, woodpile s, in mulch, in dumps, palm trees, and crawl spaces (Cornwell 1968, PCT 1995, Barcay 2004, Jacobs 2007). Indoors, the American cockroach can be found in basements, steam tunnels, sheds, and latrines. They can also be found where food is prepared or stored, such as restaurants, grocery stores, bakeries, as well as factories, hospitals, hotels, and zoos (Cor nwell 1968, Roth 1982, Barcay 2004). Another peridomestic cockroach is the Oriental cockroach, Blatta orientalis L., which is found in temperate areas of the United States preferring cool, damp environments, and temperatures below 29 C (Cornwell 1968, Thom s and Robinson 1986, Barcay 2004). Outdoors, Oriental cockroaches can be found in crawl space s, the cracks and crevic es of walls and porch 67

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voids (Thoms and Robinson 1986, Pest Management 1995). Indoors, the Oriental cockroach prefers moist, damp, cool areas, such as basements, (Blatchley 1920, Pest Management 1995, Barcay 2004) but is also found n ear radiators, ovens, and hot -water pipes (Cornwell 1968). The Oriental cockroach may be transported indoo rs via laundry or food packaging, or they may enter structures through gaps ar ound doors, windows, pipes, or cracks in the foundation (Thoms and Robinson 1986, Pest Management 1995, Barcay 2004). Additionally, the Oriental cockroach can use garbage chutes, electr ical conduits, and plumbing to move from lower areas of a structure to upper levels (Pest Management 1995). Cockroach infestations can cause psychologica l problems; due to the embarrassment they cause. The American cockroach can cause seri ous mental anguish and its presence is aggravated by swift movements and flight acro ss a kitchen counter and flying from ceiling to wall (Bell 1984). Cornwell (1976) stated that the fear or shame associ ated with cockroach infestations prevented some people from admittin g an infestation existed. The fear or shame can cause stress in proportion to the size of the cockroach and/or infestation (Brenner 1995). The stress comes from the implication that if cockro aches are present it is due to an unsanitary environment, which may or may not be the case. Cockroaches can also cause serious health problems. Cockroaches pr oduce allergens that may elicit asthma attacks. Studies on inner city children with asthma observed that these children were more allergic to cockroach allergens than to either dust mite or cat allergen s and about 50% of the bedrooms tested had enough cockroach allerg ens to elicit asthma attacks (Rosenstreich et al. 1997). Cockroaches are also able to carry, maintain, and excrete viable fungi, protozoa, eggs of helminthes, viruses, and bacteria, in cluding several strains of streptococcus and salmonella (Roth and Willis 1957, 1960). Both Amer ican and Oriental cockroaches have been 68

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associated with bacteria that cause pneumonia, food poisoning, and tuberculosis (Roth and Willis 1957, 1960, Barcay 2004). Because of aesthetic and hea lth issues, cockroach control is essential. The objective of my study was to determine if cockroach gel baits containing emamectin benzoate would be palatable to both American and Oriental cockroaches Additionally, I wanted to determine if gel baits formulated with emamec tin benzoate were capabl e of controlling both of these cockroach species. Materials and Methods Insecticides Five experimental formulated emamectin be nzoate gel baits, and one standard gel bait were tested. The experimental emamectin benz oate gel baits were formulated as either emamectin A at a concentration of 0.1% or emamectin B at a concentration of 0.05%, 0.1%, or 0.2%. One of the formulated gel baits contained no active ingredient (Sy ngenta Crop Protection, Greensboro, NC). The current indus try standard gel bait utilized in this study was Maxforce FC Select with 0.01% of the active ingredient fipron il (Bayer Environmental Science, Montvale, NJ). Insects Oriental and American cockroaches were rear ed at the University of Florida, urban entomology laboratory (Gainesville, FL) in glass utility jars (25.5 high x 22.0 cm diameter) with the inner top 5 cm greased with a petroleum jelly /mineral oil mixture (2:3) to prevent escape. Each jar contained cardboard for harborage, and were provided wate r and dry rodent food (Labdiet 5001, PMI Nutrit ion Int., Brentwood, MO) ad libitum Cockroaches were maintained at 23.6 2.5C at 51 16% RH at a photoperiod of 12: 12 (L: D). For testing, Oriental cockroach 69

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nymphs, second to fourth instars, and American cockroaches, adults and third to fifth instar nymphs, were removed from the colony with feather tip forceps. Assay Setup The test arenas were lidded transparent plas tic boxes (27 x 19.5 x 9.5 cm height), with the inner top 5 cm greased to prevent cockroach escape. For American co ckroaches, 235 mL of corncob grit (Kay-Kob Bedding and Liter, KAYTEE Products, Incorporated, Chilton, WI.) was spread on bottom of arena to absorb excess moisture. Both American and Oriental cockroach arenas contained harborage [a blank white index card (7.6 x 12.7 cm) folded lengthwise and stapled] and a water vial with a cotton stopper. A mixed population of American cockroaches (5 adult males, 5 adult females and 10 nymphs) or 10 Oriental nymphs were placed into arenas and starved for 24 h. Dead cockroaches and exuviae were removed prior to introduction of food and gel baits. Assay Method Oriental and American cockroaches were provided a choice betw een pre-weighed dog food (Purina One puppy: growth and development, Nestl PetCare Company, St. Louis, MO.) (~0.28 g) or gel bait (~0.50 or ~1.50 g, respectively) which were placed on pieces of paper (3.8 x 3.8 cm, Fisherbrand weighing paper). In cont rol assays, dog food replaced gel baits and, therefore, received dog food only. Similar amounts of dog food or gel bait were placed onto pieces of paper and into 30 ml cups, which were then covered with an organdy fabric square and held in place with a rubber band to prevent cockroach access. The covered food was used for moisture-loss controls and used to adjust for loss/gain in co nsumption calculations. The four portions, tow dog foods and tow gel baits, were placed in the arena simultaneously. After 24 h, the four portions were reweighed. The exposed dog food and gel bait were placed back into the 70

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arena for the remainder of the study. Cockroach mortality was recorded up to 14 d after the introduction of food. Mortality was defined as cockroach inability to self-right. Data Analysis Consumption was calculated as follows: Consumption = B B {B B x [(MC B MC A ) / MC B ]} B A where B B is the pre-weight of dog food/gel bait before introduction into the arena, MC B is the pre-weight of moisture control food/gel bait, MC A is the post-weight of moisture control food/gel bait 24 h after introduction into the arena, and B A it the post-weight of exposed food/gel bait (Ncherne 2006). Each portion was weighed individua lly before introduction into the arena and at 24 h after introduction. Gel bait consumption was calculated as follows: Percent consumption = [GB / (GB + DF)] x100 where GB is gel bait consumed (mg) a nd DF is dog food consumed (mg) (Ross 1998). Consumption and mortality data were analyzed by analysis of variance with means separated by Student Newman Keuls (SNK) or Students t -test ( = 0.05; SAS Institute 2003). Results Consumption Within ~5 min of food portion placement into the arena, both the Oriental and American cockroaches were observed around both the gel ba its and dog food. The Oriental cockroaches did not show a preference for either piece of dog food in the control arenas, indicating that there was no location bias (Table 5-1). The American cockro aches seemed to have a slight preference for the dog food side of the aren a over the gel bait side. For Oriental and American cockroaches, dog food had the lowest percent consumption, was significantly difference from all gel baits ( F = 7.30, df = 6, P <0.0001 and F = 88.51, df = 6, 71

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P <0.0001, respectively). However, there was no si gnificant difference in percent consumption between any of the gel baits. Mortality For both Oriental and American cockroaches, dog food and bait base percent mortalities were not significantly different from each other, but with the lowest percent mortality, they were significantly different from all other gel bait s (emamectin A 0.1%, emamectin B 0.05%, .01% and 0.2%, and Maxforce FC Select) (Table 5-2). The bait base contained no active ingredient; consequently, percent mortality was e xpected to be similar to dog food. For Oriental cockroaches, there was no significant difference in pe rcent mortality for Maxforce FC Select, emamectin A 0.1%, or emamectin B at 0.1% and 0.2% ( F = 81.83, df = 6, P <0.0001). Likewise, there was no significant differ ence in percent mortal ity between emamectin A 0.1% and emamectin B 0.05%, 0.1%, and 0.2%. Ho wever, mortality of cockroaches exposed to Maxforce FC Select was significantly different from emamectin B 0.05%. For American cockroaches, there was no signi ficant difference in percent mortality between Maxforce FC Select, emamec tin A 0.1% or emamectin B 0.2% ( F = 149.57, df = 6, P <0.0001). Additionally, there was no significant di fference in percent mortality between the emamectin B gel baits at 0.05%, 0.1% or 0.2%. Furthermore, emamectin A 0.1% and emamectin B 0.1% and 0.2% were not significantly different from each other. However, emamectin B at 0.05% and 0.1%, with the lowe st percent mortality at 85% and 92.14%, respectively, was significantly different from Maxforce FC Select There was also a significant difference in percent mortality between emamectin A 0.1% and emamectin B 0.05% (Table 5-2). For both the Oriental and American cockroach es, there was no significant difference in percent consumption between emamectin A 0.1% and emamectin B at 0.1%. Additionally, there 72

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was no significant difference in percent mortality between emamectin A 0.1% and emamectin B at 0.1%. For American cockroaches, emamectin B 0.2% had the fastest speed of action among the emamectin gel baits, with ~50% mortality at 4 to 5 d (Fig. 5-1). Emamectin A at 0.1% and emamectin B at 0.1% had similar speeds of actio n with 50% mortality at ~5 d. Emamectin B 0.05% had the slowest speed of action through the 14 d, with 50% mortality at 7 d. For Oriental cockroaches, emamectin B 0.2% had the fastest speed of action, among the emamectin gel baits, with about 50% mortality at ~4 d and 90% mortality at ~7 d (Fig. 5-2). Emamectin A 0.1% and emamectin B 0.1% had similar speeds of action with about 50% mortality at 7 d. Emamectin 0.05% had the slowes t speed of action with 50% mortality at 10 d. However, at 14 d, there was no significan t difference in percent mortality. Discussion American cockroaches climb over the top of their food and often carry it away (Frishman 1988). In my study, this behavior wa s also observed. Dog f ood was also removed from paper, which were labeled prior to in itial weighing, and could often be found in the harborage. Dog food found inside harborage was observed to have greater consumption than dog food found outside of harborage. Due to movement of dog food within cont rol arenas, individual pieces were paired with the closest piece of paper. Therefore, location bias c ould not be assessed. American and Oriental cockroaches preferre d the gel baits (bait base, Maxforce FC Select, emamectin A, and B) to dog food. American cockroaches will feed on a wide assortment of materials including glue, leat her, plants, fruit, and starch es including nuts, bookbinding, and paper (Bell 1984, Jacobs 2007). They are more attract ed to some food materi als than to others (Lofgren and Burden 1958, Ahmed 1976). Convers ely, little information exists on food 73

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preferences for the Oriental co ckroach other than prefers to feed upon starchy foods (Suiter and Koehler 1991) and prefer decaying foods (Barcay 2004). In my study, American and Oriental cockroaches overwhelming preferred the gel baits (>96% and >87% consumption, respectively) to dog food, feeding almost exclusivel y on the gel baits (Table 5-1), suggesting that American and Oriental cockroaches are attracted to the material in gel baits used in this study more than the material in the dog food. American and Oriental cockroaches are suscep tible to a variety of insecticides (Ahmed 1976, Burden 1980, Koehler et al. 1991, Valles et al. 1999). In my study, I found that both American cockroaches and Oriental cockroaches were susceptible to emamectin gel baits, which resulted in a high percent mortality, 85%, at 14 d (Table 5-2). Emamectin gel baits have a speed of action that requires 5-7 d for 50% mortality in American cockroaches. Using abamectin at about 0.05%, LT 50 s for American cockroaches were observed to be 2.1 and 3.4 d for late instar nymphs and adult males, respectively (Koehler et al. 1991 and Smith and Appel 1996). In my study, I observed that emamectin B 0.05% had the slowest speed of action with >50% mortalit y being achieved by ~7 d (Fig. 5-1). Higher concentrations of emamectin benzoate resulted in 50% mortality at ~5 d. However, by 14 d, consumption of emamectin gel baits resulted in 85% to 98% mortality of American cockroaches. This slower speed of action for the emamectin ge l baits compared to abamectin could be due to the different cockroach ages and sexes. In my study, I used mixed populations, while Koehler et al. (1991) utilized adult male American cockro aches and Smith and Appel (1996) made use of the last 2 instars. In my study, only 25% of Am erican cockroach test populations were late instar nymphs and adult males. 74

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For the Oriental cockroach, speed of ac tion of emamectin gel baits was highly concentration dependent. The abamectin LT 50 for Oriental cockroaches was observed to be 2.9 d for adult males at a concentration of 0.05% (Koe hler et al. 1991). In my study, I observed 50% mortality of Oriental cockro aches at ~10 d when fed emamectin benzoate at 0.05%. The emamectin gel baits at 0.1% required 6 to 8 d for 50% mortality of Oriental cockroaches, and just 4 d when fed 0.2% emamectin benzoate. However, by 14 d, consumption of emamectin gel baits resulted in >85% mortality of Oriental cockroaches. The slow er speed of action may be due to age of cockroaches utilized in each study. In my study, mid-instar nymphs were used, while in the Koehler et al. (1991) study, a dult males were used. Koehler et al. (1993) observed that susceptibility of German cockroaches varied by the age and sex, thus, similar susceptibility might occur in Oriental and American cockroaches. Slower speed of action may assist in horizon tal transfer of emamectin benzoate. Given that 50% mortality was not observed until after 4 d, for both American cockroaches and Oriental cockroaches, there should be ample time for defeca tion (one form of horizont al transfer) prior to mortality. Additionally, American cockroaches are repelled by the presence of other dead American cockroaches and just two cockroach e quivalents were sufficient to cause repellency for up to 4 weeks (Rollo et al. 1995). If a large number of cockroaches return to harborages and die too quickly, this may cause di spersion of untreated populations. In conclusion, both American cockroaches and Oriental cockroaches consumed large percentages of emamectin gel baits. These were comparable to the percent consumption of Maxforce FC Select. Consumption of emamectin benzoate resulted in 85% mortality, at the lowest concentration, for both species. At higher concentrat ions, 0.1% and 0.2% emamectin benzoate, 92% to 98% of American cockroaches and 88% to 91% of Oriental cockroaches were 75

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dead at 14 d. Speed of action to obtain ~ 50% mortality required 5 to 7 d for American cockroaches and 4 to 10 d for Oriental cockroach es. Such a slow speed of action could aid in horizontal transfer and ultimately resulted in high mortality for both species. Thus, emamectin benzoate appears an ideal candidate material for controlling both Am erican and Oriental cockroaches. 76

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Table 5-1. Gel bait preference of Blatta orientalis and Periplaneta americana in a 24 h choice experiment. Bait as % of total consumption (Mean sem) a Treatment Blatta orientalis Periplaneta americana Dog Food 49.5 5.61b 41.8 3.78b Blank Bait Base 91.8 4.77a 98.6 0.89a Maxforce FC Select 90.1 2.98a 96.7 2.57a Emamectin A 0.1% 87.7 6.56a 99.6 0.13a Emamectin B 0.05% 87.3 5.39a 99.2 0.44a Emamectin B 0.1% 92.4 3.22a 99.7 0.12a Emamectin B 0.2% 92.3 3.68a 99.7 0.13a a Consumed percentage was obtai ned by the following formula: {gel bait consumed (mg) / [gel bait consum ed (mg) + dog food consumed (mg)]} x 100. Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 77

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Table 5-2. Percent mortality of Blatta orientalis and Periplaneta americana at 14 d after bait introduction. Percent Mortality a Treatment Blatta orientalis Periplaneta americana Dog Food 1.4 1.43c 0.7 0.71d Blank Bait Base 0.0 0.00c 1.43 0.92d Maxforce FC Select 100 0.00a 100.0 0.0a Emamectin A 0.1% 88.6 6.7ab 98.57 0.92ab Emamectin B 0.05% 85.7 5.28b 85.00 5.67c Emamectin B 0.1% 90.0 3.09ab 92.14 2.64bc Emamectin B 0.2% 91.4 4.59ab 96.43 1.43abc a Mortality percentage was obtained by the following formula: no. of dead cockroaches dead at 14 d / no. of live cockroaches at 0 hr. Means within a column followed by the same letter are not significantly different ( P = 0.05; Student Newman Keuls [SAS Institute, 2003]). 78

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0 20 40 60 80 100 02468101214 Time in DaysPercent Mortality 16 Emamectin A 0.1% Emamectin B 0.05% Emamectin B 0.1% Emamectin B 0.2% Figure 5-1. Percent mortality for Periplaneta americana at 3, 6, 8 and 14 d after introduction of experimental emamectin benzoate baits. 79

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0 20 40 60 80 100 024681012141 Time in DaysPercent Mortality 6 Emamectin A 0.1% Emamectin B 0.05% Emamectin B 0.1% Emamectin B 0.2% Figure 5-2. Percent mortality for Blatta orientalis at 3, 6, 8 and 14 d after introduction of bait. 80

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CHAPTER 6 CONCLUSION Initially, I compared a bait averse strain a nd a standard susceptible strain of German cockroach for palatability and efficacy of gel baits containing emamectin benzoate. I observed that the gel baits formulated with emamectin benzoate were pala table to both strains and that there was no statistical difference in percent c onsumption between the strains. I also observed that both strains were susceptible to emamectin benzoate. Percent mortality was 80% to 90% for the emamectin benzoate gel baits, at 6 d. There was no statistical differenc e in mortality between the bait averse strain and the normal strain. In the succeeding experiments, the bait aver se strain of German cockroach, brownbanded cockroach, Oriental cockroach and American cock roach palatability and efficacy were observed when the cockroaches were fed gel baits containing emamectin benzoate at several concentrations. For all cockroaches tested, ther e was no statistical difference between emamectin A 0.1% and emamectin B 0.1% in percent consumption or mortality. The emamectin gel baits were palatable to all species of cockroaches The bait averse German cockroach, Oriental cockroach and American cockroach all preferred the gel baits to the standard laboratory diet of dog food. Brownbanded cockroaches showed no pr eference for gel bait or dog food, consuming a similar percent of both mate rials in choice assays. I observed good efficacy of the emamectin gel baits. Percent mortality for all cockroach species was between 85% and 99.5 % after consuming emamectin benzoate gel baits. Percent mortality for the brownbanded cockroach and the bait averse German cockroach was similar for all formulated gel baits tested: emamectin A, em amectin B, and the standard Maxforce FC Select gel baits. Percent mortality for the Oriental cockroach was similar for emamectin A and emamectin B and only emamectin B 0.05% was statis tically different from Maxforce FC Select. 81

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Percent mortality for the American cockroach was similar for the emamectin B gel baits, only emamectin B 0.05% was statistically different from emamectin A 0.1% and only emamectin B 0.05% and 0.1% were statistically di fferent from Maxforce FC Select. In each of my studies, I observed that the expe rimental gel bait matrices were palatable to all species and strains of pest cockroaches test ed. I also observed high percent mortality for all cockroaches tested when fed emamectin benzoa te. Gel baits with emamectin benzoate show excellent commercial potential for controlling both domestic and peridomestic cockroaches. 82

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LIST OF REFERENCES Ahmed, S. M. 1976. Comparative efficacies of various inse cticides in a new bait formulation against Periplaneta americana Int. Pest Control 18: 4-6. Appel, A. G. 1995. Blattella and related species, pp 1-19. In M. K. Rust, J. M. Owens, and D. A. Reierson [eds.], Understanding and controlling the German cockroach Oxford University Press, Inc., New York, NY. Appel, A. G., and E. P. Benson. 1995. Performance of abamectin bait formulations against German cockroaches (Dictyoptera: Blatte llidae). J. Econ. Entomol. 88: 924-931. Atkinson, T., P. G. Koehler, and R. S. Patterson. 1990. Annotated checklist of the cockroaches of Florida (Dictyoptera: Blatta ria: Blattidae, Polypha gidae, Blattellidae, Blaberidae). Fl. Entomol. 73: 303-327. Atkinson, T., P. G. Koehler, and R. S. Patterson. 1991. Geography of cockroaches in the U.S. Pest Control. 59: 36-38, 40. Barcay, S. J. 2004. Cockroaches, pp. 120-215. In Hedges S. A. and D. Moreland [eds.], The Mallis handbook of pest control. GI E Media, Inc., Richfield, OH. Barile, J. 2003. In Stayin alive. By B. Harbison, R. Kramer, and J. Dorsch. Pest Control Technol. 31: 24-29, 83. Bell, W. J. 1984. Bionomics and control of the American cockroach: Part one. Pest Mgmt. 3: 1219. Bernays, E. A. 1985 Regulation of feeding behaviour, pp. 1-32. In L. I. Gilbert and K. Iatrou [eds.], Comprehensive molecular insect phys iology, biochemistry, and pharmacology. vol. 4. Pergamon Press, New York, NY. Blatchley W. S. 1920. Orthoptera of Northeastern Ameri ca. The Nature Publishing Company, Indianapolis, IN. Braness, G. A. 2004. Insecticides & pesticide safety, pp. 1098-1163. In S. A. Hedges, and D. Moreland [eds.], The Mallis handbook of pest c ontrol. GIE Media, Inc., Richfield, OH. Brenner, R. J. 1995. Economics and medical importance of German cockroaches, pp. 77-92. In M. K. Rust, J. M. Owens, and D. A. Reie rson [eds.], Understandi ng and controlling the German cockroach. Oxford University Press, New York. Brenner, R. J., P. G. Koehler, and R. S. Patterson. 1987. Health implications of cockroach infestations. Infect. Med. 4: 349-355, 358-359, 393. Brenner, R. J., K. C. Barnes, and R. M. Helm. 1990. Arthropod allergens in the urban environment, pp. 57-66. In Proceedings of the National Conference on Urban Entomology. 83

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Grosman, D. M., and W. W. Upton. 2006 Efficacy of systemic insecticides for protection of Loblolly pine against southern pine engr aver beetles (Coleopt era: Curculionidae: Scolytinae) and wood borer s (Coleoptera: Cerambycidae). J. Econ. Entomol. 99: 94-101. Guthrie, D. M., and A. R. Tindall. 1968. The biology of the cockro ach. St. Martins Press, New York, NY. Hoy, M. A. 1999. Myths, models and mitigation of resistance to pesticides, pp. 111-119. In I. Denholm, J. A. Pickett and A. L. Devons hire [eds.]. Insecticide resistance: from mechanisms to management. CABI Publishing, New York, NY. Ishaaya, I., S. Kontsedalov, and A. R. Horowitz. 2002. Emamectin, a novel insecticide for controlling field crop pests. Pest Manag. Sci. 58: 1091-1095. Jacobs, S. B. 2007. American cockroaches. ( http://www.ento.psu.edu/extension/ factsheets/amer_cockroach.htm ). Pub. HP-4. Pennsylvania State Universi ty, University Park, PA. Jansson, R. K., R. F. Peterson, W. R. Halliday, P. K. Mookerjee, and R. A. Dybas. 1996. Efficacy of solid formulations of Emamectin benzoate at controlling lepidopterous pests. Fl. Entomol. 79: 434-449. Jansson, R. K., R. F. Peterson, P. K. Mookerje e, W. R. Halliday, J. A. Argentine, and R. A. Dybas. 1997. Development of a novel soluble granule formulation of emamectin benzoate for control of lepidopterou s pests. Fl. Entomol. 80: 425-443. Jansson, R. K., and R. A. Dybas. 1998. Avermectins: biochemical mode of action, biological activity and agricultura l importance, pp. 152-170. In I. Ishaaya, and D. Degheele [eds.], Insecticides with novel mode s of action: mechanisms and application. Springer, New York, NY. Kendall, D. 2005. Insect fossils. ( http://www.kendall-bioresearch.co.uk/fossil.htm ). Kendall Bioresearch Services, Bris tol, United Kingdom. Koehler, P. 2006. In German cockroaches winning the war against pest control baits. By C. Woods. ( http://news.ufl.edu/2006/12/06/german-roaches/ ). UF News Desk, Gainesville, FL. Koehler, P. G., T. H. Atkinson, and R. S. Patterson. 1991. Toxicity of abamectin to cockroaches (Dictyoptera: Blattel lidae, Blattidae). J. Econ. Entomol. 84: 1758-1762. Koehler, P. G., R. S. Patterson, and J. M. Owens. 1995. Chemical systems approach to German cockroach control, pp. 287-323. In M. K. Rust, J. M. Owens, and D. A. Reierson [eds.], Understanding and controlling the German cockroach. Oxford University Press, New York, NY. 86

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BIOGRAPHICAL SKETCH Barbara Ellen Bayer was born on January 20, 1971, in Fort Myers, Florida. The second of three girls, she grew up in Tampa, Florida, graduating from King High School in 1989. She attended Hillsborough Community College beginning in January 1990, transferring to the University of Florida in May 2003. She earned her B.S. in urban entomology from the University of Florida in 2005. Barbara has held a variety of jobs, mostly in the accounting field, working at JC Penney from August 1990 to May 1996. She then worked for Housecall Home Health Care for a short period, May 1996 to January 1997. Barbar a then went to work with her uncle at Gulfside Supple from January 1997 to August 1999. She then had th e honor of working for Famous Tate from August 1999 until August 2005. Barbara was a graduate assistant under Dr. Philip Koehler from August 2005 to August 2007, when she completed he re Master of Science (MS) degree. Upon completion of her MS program, Barbara was given the opportunity to continue her education and earn her Ph.D. in entomology at the University of Florida. 93