THE EFFECTS OF THREE INSECTICIDES ON OOTHECAL-BEARING GERMAN COCKROACH, Blatt.~.ll.a. ~.e..r.m.a..lJ..lla L. • (DICTYOPTERA: BLATTELLIDAE), FEMALES. by James Dale Harmon Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Entomology APPROVED: l<&<>"' l y c - w: R.D. Fell W. H Robinson June, 1987 Blacksburg, Virginia THE EFFECTS OF THREE INSECTICIDES ON OOTHECAL­ BEARING GERMAN COCKROACH. Blattella ~manica L. (DICTYOPTERA:BLATTELLIDAE), FEMALES by James Dale Harmon Committee Chairperson: Mary H. Ross Entomology (ABSTRACT) German cockroach. :6.lattella i,ermanica L •• females .. of resistant and non-resistant strains carrying oothecae were exposed to filter paper impregnated with propoxur. malathion. and diazinon. Premature oothecal drop was monitored during the exposure period and for 24 hours thereafter. Dete.rminations of female mortality were also made 72 h post-exposure. Oothecae from exposed fema.les were observed for percentage egg hatch. time from exposure to hatch. percentage nymphal emergence. nymphal survival. and the percentage of nymphs able to move about freely 24 hours post-emergence. The comparisons of these factors were made not only on prematurely dropped oothecae but also on oothecae retained by females. and . oothecae that were manually detached from females. Premature oothecae dropped and those manually detached were hatched on an insecticide treated surface. Premature oot beca 1 drop occurred in a 11 experiments • but was delayed 24 b in expe~iments with organophosphates. The mortality of treated females which prematurely dropped their oothecae was higher than females retaining them (73% vs. 53%). Percentage nymphal emergence and survival were reduced when oothecae were placed on an insecticide treated surface. The significantly higher survival of resistant strain nymphs (Carver. 60%. and Lynn Haven. 99%) in a comparison to nymphs of a susceptible strain (VPI. 45%) on insecticide treated surfaces provides evidence for resistance in first instar nymphs. A procedure for the quantitative comparison of the effects of different insecticides on ootbec a 1-bear ing females bas ·been developed. Insecticides which cause a higher percentage of premature oothecal drop may reduce regrowth of a cockroach population when compared to materials which do not. even if the insecticides cause similar mortality. The extent to which population regrowth occurs depends on whether oothecae batch on a treated surface. oothecal age. and environmental conditions. ACBOWLEDGEMEBTS The culmination of a graduate program is not to be solely attributed to the grad]!ate student. Many thanks go to my committee members for their help and guidance over the last two years, Drs. W"• H Robinson and R.D. Fell. Of course, to my major advisor, Dr. Mary H. Ross, I owe a great debt of thanks for her support and guidance throughout my program. While the committee members are usually thought of as a major part of a graduate student's career, there are many others within the department to which I will be forever grateful for their help and assistance. Drs. R.L. Pienkowski and D.E. Mullins for teaching me the skills of being an effective communicator and instructor; Dr. J.A. Weidhaas for an education in ornamentals and organization; for all the help in the cockroach lab and the darkroom; and all of the faculty, staff, and students of this department for their support and friendship. Many thanks also go to Deans R.A. Teekell, M.J. Johnson, B. LaBerge, and the Graduate Student Assembly for all of their help, support, guidance, headaches given and shared, and for the experiences within the GSA which have greatly helped me in my development as an administrator. Another debt of thanks is owed to my family and friends outside the Entomology Department for putting up with l.V someone who studies "bugs and roaches ... Their continued support in all times was a distinct asset to my graduate experience. Lastly. I would like to thank the members of the Newman community. especially· and for their support. guidance and conversation during my own conversion and development. v LIST OF TABLES I able. 4.1. Effect of propoxur on mortality and oothecal drop on female .lL. ,i_ermanica carrying Stage XII oothecae (oot) ••••••••• 34 4.2. Effects of propoxur on hatch of a~d nymphs from Stage XII .lL. ~ermanica oothecae ( oot) •••••••••••••••••••••••••••• 35 5 .1. Effect of ma~athion on mortality and oothecal drop on female .lL. ,i_ermanica carrying Stage XII oothecae (oot) ••••••••• 50 5.2. Effects of malathion on hatch of and nymphs from Stage XII .lL. ~exmanica oothecae (oot) ••••••• ~··•••••••••••••••••• 51 5.3. Effect of diazinon on mortality and oothecal drop on female JL.. iermanica carrying Stage XII oothecae (oot) ••••••••• 52 5.4. Effects of diazinon on hatch of and nymphs from Stage XII .lL. ~anica oothecae (oot)•••••••••••••••••••••••••••• 53 v~ LIST OF FIGURES Pyrex glass chimney (19 em X 14.5 em · inside diam.) lightly coated with vaseline around'the base and enclosing a treated filter paper •••••••••••••••••••• 23 3.2. Sealed 0.9 1 jar used for placement of prematurely dropped oothecae on treated filter paper until hatch •••••••••• 23 4.1. Nymphs. pigmented and unpigmented. still entangled in'embryonic cuticle 24 h afte~ emergence on a propoxur treated surface •••••••••••••••• 36 4.2. Fully pigmented nymphs being unable to completely shed embryonic cuticle on antennae (65X} ••••••••••••••••••••••••• 36 4.3. Pigmented (~live) and unp~gmented (dead) nymphs still encased in embryonic c u t i c 1 e • • • • • • • • • • • • • • • • • _. • • • • • • • • • • • • • • • • • 3 7 4.4. Nymph still attached~to ootheca by embryonic cuticle encasing metatarsi (27.7X).~••••••••••••••••••••••• 37 TABLE OF COBTEBTS ABSTRACT •••••••• •-• ••••••••••••••••••••••••••••••••••••••• ii ACKNOWLEDGEMENTS••••••••••••••••••••••••••••••••••••••••• iv LIST OF TABLES~~·•••••••••••••••••••••••••••••••••••••••• vi LIST OF FIGURES ••••••••••••••••••••••••••••••••••••••••• vii I • INTRODUCTION ••••••• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 II. LITERATURE REVIEW BIOLOGY OF L i e rman i.s:..a. • ••••••••••••••••••• 3 EFFECTS OF INSECTICIDES ON THE LIFECYCLE OF L ~ermanica. • • • • • • • • • • • • 4 EFFECTS OF INSECTICIDES ON REPRODUCTION AND OVIPOSITION OF INSECTS OTHER THAN COCKROACHES •••••••••• • • • • • • • • • • • • 5 RESISTANCE••••••••••••••••••••••• . .. 6 Physiological Resistance •••• • • • • • • • • • • 6 Behavioral Resistance ••••••• .. .. .. 7 OOTHECAE ••••••••••••••••••••••••• . .. .. 8 EFFECT OF ENVIRONMEN~ ON OOTHECAL DROP AND HATCH IN L ~ermanica ••••••• 10 EFFECTS OF INSECTICIDES ON OOTHECAL DROP AND HATCH IN L ~ermanica •••••••••••• 12 III. MATERIALS AND METHODS CHEMICALS •••••••• . .. .. .. .. .. .. .. 15 COCKROACH STRAINS ••••••••• • • • • • • • • • • • • • • • • • • • • • 15 TECHNIQUES••••••••••••••••••••••••••••••••••••• 16 Cu l.ture •••••••••••••••••••••••••••• ••••••• 16 Selection of Oothecal Bearing Females ••••• 17 Dosage Determination •••••••••••••••••••••• 18 Tarsal Contact Method••••••••••••••••••••• 18 EXPERIMENTAL PROCEDURES•••••••••••••••••••••••• 19 CALCULATIONS ••••••••••••••••••••••••••••••••••• 20 DATA ANALYSIS•••••••••••••••••••••••••••••••••• 21 IV. EXPERIMENTS USING PROPOXUR INTRODUCTION•••••••••••••• • • • • • • • • • • • • • • • • • • ••• 24 MATERIALS AND METHODS ••••• • • • • • • • • • • • • • • .... • • • 26 RESULTS •••••••••• . ... • • • • • • • • • • • • • • • • • • • • • ••• • • • 26 DISCUSSION•••••••••i••••••• • • • • • • • • • • • •• • • . • • • 29 v. EXPERIMENTS USING ORGANOPHOSPHATES INTRODUCTION •••••••••• • • • • • • • • • • • • • • •• • • • • . .. 38 MATERIALS AND METHODS ••••••••• . .. • • • • •• • • • •• 39 RESULTS ••••••••• •• • • • • • • • • • • • • • • • • • • • • • • • • •• • • • 40 DISCUSSION.•••••••••••• • • • • • • • • .. .. • • •• •• • • • 45 VI. DISCUSSION AND CONCLUSIONS. ............ ~ ............ 54 VII. LITERATURE CITED••••••••~••••••••••••••••••••••••••• 62 l.X l. IBTR.ODUCTIOB. The German cockroach. Blattellll ~ermanli11 ( L •) (Dictyoptera: Blattellidae). is one of the most common cockroach pests in human dwellings (Cornwell. 1968). The German cock roach. t bought to have or ig ina ted in east Asia (Roth. 1985). has become worldwide in distribution. The reproductive potential of the German cockroach is such that a population. if uncontrolled. can increase 24 to 28 times in 3 months (Ross. et. al •• 1984). The obvious need for control of this pest has prompted control efforts using insecticides. Selection pressure from such efforts has resulted in the development of resistance to many insecticides. Resistance in the German cockroach has been well known since the early 1950's (Cornwell. 1976). A considerable amount of information is available on the effects of lethal dosages of insecticides on cockroaches • however. comparably little is known about the effects of sublethal dosages on reproduction and oviposition. The inducement of premature oothecal drop in gravid female German cockroaches has been recognized as an effect of sublethal insecticide dosages. but very little is known about it. The ootheca is the most environmentally resistant stage in the life cycle of the German cockroach (Van den Heuvel and Shenker. 1965). Information on 1 2 insecticide induced premature oothecal~ drop is very important to the planning and implementation of pest control strategies. Variations of