Effect Of Temperature On Biological Characteristics Of Bemisia Tabaci Biotype B In Euphorbia Pulcherrima

Bemisia tabaci biotype B is a small polyphagous piercing and sucking insect, which has become a principle pest harmful to crops and economic plants in our country and a threat to yield of vegetables, ornamental plants and cotton. Global warming is one of important factors to its outbreak in recent years. In this study.Bmisia tabaci biotype B is treated at different temperatures of22℃,25℃,28℃,31℃and34℃and to study its ecological adaptability, activities of protective enzymes and detoxifying ones, and tolerance to imidacloprid. The study provides a theorical basis to formulate its control strategy. The results show as follows.1.Developmental duration, livability and life table parameters at different temperatures of Bemisia tabaci biotype B are clarified. The developmental duration and livability of Bemisia tabaci biotype B in Euphorbia pulcherrima var.millenium under different temperatures of22℃,25℃,28℃,31℃and34℃, illumination perilod14L:10D and humidity60-70%are studied. Livability of the test insect developing from egg to adult at5different temperature is45.051,57.89,65.15,39.51,50.96, respectively. The life cycle is shortest under28℃and longest under2℃, which is21.37and26.32days, respectively. The adult age is longest under22℃and reach24.71days, and shortest under25X2which reach9.83days. The spawning amount of average each female at5different temperature is157.57.79.83,75.57.48.40and46.57. Intrinsic growth rate is largest under25X2and smallest under22℃. The suitable temperature for its growth and development is25℃and28℃.2. Activity of protective enzymes and detoxifying ones in Bemisia tabaci biotype B are studied at different temperatures. There was no significant difference of SOD and CAT in the range of22-34X2. However, the activities are positively correlative to liabilities. The activities of CarE, GSTs and AchE in their male or female bodies at a certain temperature is different. The activity of CarE in their female bodies fluctuates as temperature rises and reach a maximum at28℃. The activities of GSTs rise gradually and reach a maximum at34℃, while the activity of AchE drops and reaches a minimum at34X2. With the increase of temperature,the activity of CarE and AchE in male bodies shows a. tendency to decline, and reaches a minimum at34X2. While GSTs rise gradually and reach a maximum at34℃, oppositely. The activity of AchE is negatively correlated with the control effect of imidacloprid under various temperatures. Oppositely,the activitities of GSTs are positively correlated with the control effect of imidacloprid,3. the control effect of imidacloprid to different development stage of Bemisia tabaci biotype B at different temperature is also clarified. The control effect is going up with the increase of temperature. When the temperature and the concentration of pesticide rise34℃and60mg/L, the mortality of young nymph, old nymph and adult all reach above89%. From the study, we deduce that the rise of temperature acts as a positive function to control Bemisia tabaci biotype B.This study provides a theoretical foundation for forecast of the change tendency and control of Bemisia tabaci biotype B population under the wanning climate.