Toxicity, Resistance And Sublethal Effects Of Selected Insecticides On German Cockroaches, Blattella Germanica (L.) (Dictyoptera: Blattellidae) In Malaysia
| dc.contributor.author | Chow Yang, Lee | |
| dc.date.accessioned | 2018-06-01T03:14:49Z | |
| dc.date.available | 2018-06-01T03:14:49Z | |
| dc.date.issued | 1995-12 | |
| dc.description.abstract | This study which focuses on the German cockroach has dealt with sev.eral aspects of toxicity, resistance and sublethal effects of selected insecticides. ThiJteen insecticides (alpha-cypermethrin, beta-cyfluthrin, bencliocarb, bifenthrin, chlorpyrifos, cypermethrin, cyphenothrin, deltamethrin, etofenprox, fenitrothion, lambda-cyhalothrin, permethrin and propoxur) were tested topically against susceptible adult German cockroaches. Lambda-cyhalothrin was the most toxic compound against both sexes, while propoxur and bencliocarb were least toxic to male and female, respectively. Intrinsic and extrinsic factors (age, pretreatment starvation, immobilizing technique, and time of insecticidal application) were found to affect adult male susceptibility to propoxur; however, susceptibility to deltamethrin was not dependent on the last two factors. Insecticide resistance status and the possible .r esistance mechanisms involved in field German cockroaches in Malaysia were studied for the first time. Twelve strains collected· from hotels, ·restaurants and naval ships in several locations in Peninsular Malaysia were te.sted topically for their susceptibility to insecticides. Resistance levels at LD50 were low to high (2.8- to 91.7 -fold) for carbamates, low (2.0- to 7.6-fold) for organophosphates and low to moderate (1.0- to 52.3-fold) for pyrethroids. Five strains were also resistant to DDT. Synergism studies with PBO and DEF® on ten strains suggested the involvement of monooxygenases and esterases in propoxur resistance. Cypermethrin and permethrin resistance were not suppressed when using either synergists. Four resistant strains were further chosen to chru·acterize the resistance mechanisms involved using biochemical assays. Elevated esterase (low to moderate frequency) and altered acetylcholinesterase (low frequency) were detected in all four strains, while elevated glutathione S-tnmsferase were present gel electrophoresis, showed a greater banding intensity in Et, Es and E1 bands·in the resistant strains than in those of the susceptible strain. Five field strains studied demonstrated longer nymphal development, preoviposition and incubation periods, lower fecundity and shorter longevity than the susceptible strain. Susceptible strain had a higher intrinsic rate of increase (rn) than a field strain, but similar to that of another field strain. Nymphal sexratios, however, were similar among all strains. The sublethal effects of deltamethrin, propoxur and chlorpyrifos on adult longevity and fecundity were studied by reciprocal crossing. The longevity and fecundity of treated insects reduced with increasing sublethal doses of deltamethrin and propoxur; however, an inconclusive result was obtained for chlorpyrifos. Preoviposition and incubation periods were inflependent of the three insecticides. Both treated females and males showed significant effects on oothecal hatchability and nymphal production; however, oothecal production was not dependent on the latter sex. Sublethal doses of.deltamethrin, propoxur and chlorpyrifos did not result in an increase of insecticidal tolerance in the F1 generation. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/5630 | |
| dc.subject | Biological Sciences | en_US |
| dc.subject | Toxicity | en_US |
| dc.title | Toxicity, Resistance And Sublethal Effects Of Selected Insecticides On German Cockroaches, Blattella Germanica (L.) (Dictyoptera: Blattellidae) In Malaysia | en_US |
| dc.type | Thesis | en_US |
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