Effects Of Temperature Hardening And Interactive Stresses On Survival And Fecundity Of Bemisia Tabaci Q-Biotype

The sweet-potato whitefly,Bemisia tabaci (Gennadius),is one of the most serious insect pests around the world. Damage may be caused by sucking plant sap or secreting honeydew to affect photosynthesis of plants,or by transmitting different types of plant viruses,which caused a great loss on agricultural production. Based on biology characteristics such as host range,the ability of transmitting viruses,pesticides resistance,etc.,the whiteflies were divided into several biotypes. It was reported that there were at least 26 biotypes by 2005. In recent years,researchers from around the world have paid high attention on Q biotype B. tabaci. It was showed that Q biotype existed in Yunnan,Henan,Beijing,etc. in recent studies,and it was speculated that Q biotype might be derived from the Iberian Peninsula. Q biotype B. tabaci has wider range of host plants,higher survival rate,stronger fecundity and pesticides resistance,and stronger ability in transmitting plant viruses than any other biotype has. In recent years,Q biotype has expanded its distribution around the world and caused greater damage than B biotype did. Thus,the invasion biology of Q biotype has become one of hot researches internationally.The present study aimed to reveal the relation between temperature stress tolerance and population dynamics of Q biotype B. tabaci. And survival rate,longevity and fecundity of adults were investigated after temperature hardening and interactive stresses in the study. The main results were as follows:1 Compared with the control (26℃),After temperature hardening or interactive stresses,the survival rate of B. tabaci Q biotype adults was decreased significantly.2 The resistance of B. tabaci Q biotype adults to extreme high temperature could be significantly increased after non-lethal low temperature hardening. The survival rate of adults was increased from 49.4% to 69.2% at 45℃for 1h with a pretreatment of 10℃for 0.5h. However,there was not significant effect on heat resistance of B. tabaci Q biotype adults after high temperature hardening.3 There was differential heat resistance between females and males of Q biotype B. tabaci. The longevity was shortened in both sexes after temperature hardening and interactive stresses. In addition,there was a higher heat resistance in females than that in males under the same stress condition. 4 There was not significant effect on fecundity of B. tabaci Q Biotype after temperature hardening and interactive stresses. The fecundity was decreased after a pretreatment of 10℃or 33℃for 0.5h or low temperature treatment following high temperature stress. However,the fecundity was increased with a pretreatment of 39℃for 0.5h or high temperature treatment following low temperature stress.The study showed that there was differential resistance in B. tabaci Q biotype under different stress conditions,which were important factors to B. tabaci Q biotype population size dynamic. Furthermore,the research results might provide an important theoretical basis for occurrence and prediction of B. tabaci Q biotype,and had important theoretical and practical significance for sustainable control of B. tabaci Q biotype.