تاثیر سینرژیست ها بر بازدارندگی فعالیت آنزیم های سم زدا و حساسیت به کنه‌کش‌ها در کنه Rhizoglyphus robini

The saffron bulb mite, Rhizoglyphus robini Claparede (Acari: Acaridae), is the most important pest of saffron in Iran. This pest attacks and feeds on saffron corms. For this reason, the corms are treated by acaricides before planting. The high activity of detoxification enzymes in arthropods may reduce their sensitivity to pesticides. Diethyl maleate (DEM) is an inhibitor of glutathione S-transferases (GSTs), piperonyl butoxide (PBO) is an inhibitor of cytochrome P450 monooxygenases, and triphenyl phosphate (TPP) is an inhibitor of esterase activity. A filter paper dipping method was used to determine the efficiency of these synergists in inhibiting the activity of detoxifying enzymes of R. robini. Adult mites were treated with each of these three synergists for 6, 12, 24 and 48 hours respectively. Then the activity of each of detoxifying enzyme was measured and compared to the control treatment and the inhibition percentage of the enzyme activity was calculated for each time period. The results showed that pretreatment with DEM reduced glutathione S-transferase enzyme activity by 3%, 13%, 60% and, 60.5%, respectively, 6, 12, 24 and 48 hours after treatment. Also, inhibition of cytochrome P450 enzymes activity in pretreatment with PBO compared to the control was estimated as 5%,14%, 29% and, 31.3%, respectively. The activity of esterases was inhibited by 3%, 5%, 38% and, 40%, respectively, after pretreatment with triphenyl phosphate. The results showed that the most statistically significant inhibition of the detoxifying enzyme activities occurred in 24 hours after pretreatment with each of the tested synergists. Bioassays with pretreatment of each of the synergists for 24 hours showed that the sensitivity of R. robini to propargite acaricide was increased compared to that of the control, by 1.6 fold with PBO, 1.7 fold with TPP and 2.5 fold with DEM. In conclusion, the appliocation of synergists and the efficient inhibition of detoxifying enzymes can play a significant role in increasing the sensitivity of agricultural pests to pesticides and its potential can be considered in managing pesticide resistance.