RESUMO
The conditions for cultivation of malaria mosquito larvae were found to exert a great impact on their sensitivity to bactoculicide. Elevating keeping temperatures for An. sacharovi and An. pulcherrimus by 10-11 degrees C causes 2-4-fold increases in LC50. There are virtually no impacts of larval population during their development or temperature-population density relationships. Ten-fold increases in larval population density under which An. stephensi larvae have been grown result in 3-fold decreases in LC50. There are no impacts of temperatures and temperature-population density relationships either. There are also great larval species-specific differences in their sensitivity to bactoculicide.
Assuntos
Anopheles , Toxinas Bacterianas , Inseticidas , Animais , Anopheles/crescimento & desenvolvimento , Calefação , Larva , Dose Letal Mediana , Controle de MosquitosRESUMO
The dispersion of testing results is due not only to an error in the representative choice of specimens for an experiment, but also to the specific features of each specific experiment. In defining the confidence interval of the value of insecticidal activity it should not be oriented to data on variability of individual tests rather than to the error in the dose-mortality regression representativeness. The test permits one to establish differences in the insecticidal activity of the agents which differ in this index at least by 1.5-fold.
Assuntos
Bacillus , Culex , Inseticidas , Controle de Mosquitos , Animais , Relação Dose-Resposta a Droga , Larva , Métodos , Compostos OrgânicosRESUMO
Laboratory experiments have brought the authors to a conclusion on the efficacy of B. thuringiensis and B. sphaericus-based insecticides in salty water mosquito breeding sites. Species difference of mosquito larvae susceptibility to the insecticides related to salt concentration in water were detected.
Assuntos
Bacillus thuringiensis , Bacillus , Inseticidas , Controle de Mosquitos , Aedes , Animais , Culex , Água Doce , Larva , Compostos OrgânicosRESUMO
The LD50 logarithm of Bacillus thuringiensis and B. sphaericus toxins effects on the larvae of Aedes aegypti and Culex pipiens is in inverse correlation with the water temperature. The influence of the temperature on the toxins effect on C. pipiens larvae is higher than that for A. aegypti larvae. Similarly, B. sphaericus toxin effect depends on the water temperature to a greater measure than that of B. thuringiensis toxin. The authors predict a high efficacy of B. sphaericus-based insecticides in hot climate countries.
Assuntos
Aedes , Culex , Água Doce , Inseticidas , Temperatura , Animais , Bacillus thuringiensis , Toxinas Bacterianas , Relação Dose-Resposta a Droga , Larva , Dose Letal Mediana , Especificidade da EspécieAssuntos
Aedes , Bacillus thuringiensis , Bacillus , Toxinas Bacterianas , Culex , Inseticidas , Controle de Mosquitos/métodos , Animais , Larva , Temperatura , Fatores de TempoAssuntos
Anopheles , Resistência a Inseticidas , Animais , Comportamento Alimentar , Larva , Dose Letal MedianaRESUMO
The action of bacterial insecticides based on Bacillus thuringiensis H-14 and B. sphaericus in a dose of 0.005-2 mg/l on the mermithids Romanomermis iyengari, R. culicivorax and R. jingdeensis was studied. It was shown that though bacterial agents suppressed mermithid preparasite larvae density about 30-40%, the survivors might invade 100% of mosquito larvae. The viability and fertility of adult mermithids did not change under the influence of bactoculicide in doses 5-50 times higher than those used against mosquitoes in practice. In combined field trials of sphaerolarvicide (1.5 kg/ha) and R. iyengari mermithids the infectivity of Anopheles sacharovi larvae reached 96%. Mermithids in combination with bactoculicide and sphaerolarvicide might be useful in integrated control systems because these bacterial agents are harmless for mermithids of all stages in doses useful against mosquito larvae.
Assuntos
Anopheles , Bacillus thuringiensis , Bacillus , Toxinas Bacterianas , Inseticidas , Mermithoidea , Controle de Mosquitos/métodos , Animais , Relação Dose-Resposta a Droga , Fertilidade/efeitos dos fármacos , Larva , Compostos OrgânicosRESUMO
Considerable differences have been detected in the sensitivity of various Anopheles species to bacterial insecticides. These differences might be associated with features in larval nutrition and do not depend on their size and taxonomic species position. An. pulcherrimus or An. sacharovi and An. stephensi species are suggested as the most suitable test objects for the representatives of the given genus.
Assuntos
Anopheles , Bacillus , Inseticidas , Animais , Bacillus thuringiensis , Resistência a Inseticidas , Larva , Compostos Orgânicos , Especificidade da EspécieRESUMO
It has been established that the duration of exposition and the availability of larval feed have a reliable effect on the index of insecticide activity (LC-50) of bacterial preparations as regards mosquito larvae. High degree of correlation between the results obtained in different conditions makes it possible to calculate the LC-50 values for any combination of exposition and feed availability, if an index for one of the combinations is known (the formula is presented). The proposed variant of test conditions (daily exposition without larval feed) ensures a more rapid achievement of the results and reduction in labour expenses.
Assuntos
Aedes , Toxinas Bacterianas , Culex , Inseticidas , Animais , Bacillus , Bacillus thuringiensis , Comportamento Alimentar , Larva , Compostos Orgânicos , Fatores de TempoRESUMO
A self-reproducing colony of the above-mentioned mosquito species has been cultured by using individuals caught in the Tadjik SSR. The colony is maintained for 8 months (18 generations).
Assuntos
Anopheles/crescimento & desenvolvimento , Animais , Animais de Laboratório , Larva/crescimento & desenvolvimento , TadjiquistãoRESUMO
Insecticides on the base of Bacillus thuringiensis and B. sphaericus proved to be ineffective against laying of eggs by female mosquitoes in the water containing these formulations.