FRESENIUS ENVIRONMENTAL BULLETIN, cilt.25, sa.7, ss.2461-2465, 2016 (SCI-Expanded)
In this study we determined the resistance development potential to spiromesifen and changes in esterases (EST), glutathione S-Transferases (GST), cyctochrome P450 Monooxygenases (P450) and acetylcholinesterases (AChE) enzyme activities of the B and Q biotypes of cotton whitefly Bemisia tabaci (Genn.). Leaf dip bioassay was used to calculate lethal concentration (LC50) values of the biotypes. Spiromesifen was applied to first nymph stage at different dosages. Selection bioassays were carried out for the assays described above. After 8 selection with spiromesifen, the resistance to spiromesifen resulted in 3.5 fold increase in B biotype, 2 fold in Q biotype. EST activity was increased by 21.5 fold in Q biotype, 1.61 fold in B biotype and the changes in EST activity was statistically significant in Q biotype but not in B biotype. AChE activity was increased by 2.50 fold in B biotype, 2.26 fold in Q biotype and the changes in AChE activity was statistically significant in both B and Q biotypes. P450 activity was increased by 1.08 fold in B biotype, 1.77 fold in Q biotype and the changes in P450 activity was statistically different in Q biotype but not in B biotype. There was negative change in GST activity in both biotypes. After selection with spiromesifen, there was an increase in EST activity which was higher in Q biotype than B biotype. The results showed that EST activity is more significant in resistance mechanism to spiromesifen than AChE and P450 activities.