Studies on susceptibility of different developmental stages of Bemisia tabaci Gennadius (Hem., Aleyrodidae) to pyriproxyfen and citowett oil

This pest strongly demonstrates resistance against chemical pesticides and decreases the yield of cotton and worsens its quality as well. Since Biorational pesticides are generally desirable، believing to have less disturbance of the environment; this research covers the study of susceptibility of different developmental stages of Bemisia tabaci Gennadius to pyriproxyfen، citowett oil and their mixture too. Citowett oil and pyriproxyfen have been used in 5 concentrations and control treatment. The LC50 value of pyriproxyfen for adult، egg، and immature stages was 10، 45. 04 and 11. 47 PPM، respectively. This criterion to citowett oil for adult، egg; and immature stages was 1554، 884. 79 and 684. 70 PPM in the same order. To evaluate the synergistic effect of citowett oil on pyriproxyfen we used the mixture of LC25 of either compound. The results revealed that there are 52. 36%، 62. 32% and 69. 19% mortality rate for adult، egg، immature stages respectively. The experiments showed that citowett oil is able to enhance efficiency of pyriproxyfen.