Acetylcholinesterase [AChE] Activity of Colorado Potato Beetle Populations in Serbia Resistant to Carbamates and Organophosphates

Abstract

The resistance levels of the Colorado potato beetle (CPB) in Serbia to organophosphorus (OP) and carbamate (C) insecticides varied by population. The resistance level of populations to OPs indescending order was: Futog, Ratari, Dobanovci and Pester. Most resistant to carbarylwere populations Dobanovci and Ratari, followed by Futog, Kaona, and Pester, respectively. The order of resistance levels for OPs and C was completely opposite. Experiments showed that acetylcholinesterase (AChE) activity of CPB was verypronounced and easily measured. At a constant AChE concentration, increasing thesubstrate concentration will cause a positive, linear and dependent increase in thereaction. The same applies in the reaction with constant substrate concentration andincreased enzyme concentrations. AChE activity is significantly affected not only bylocation but also by substrate concentration (acetylthiocholine iodide ATChI). At low substrate concentrations, the highest AChE activity was determined in population Dobanovci, followed by Kaona, Ratari and Futog, respectively. At high substrate concentrations, however, the highest AChE activity was determined in population Ratari and then in Dobanovci and Futog. The lowest rate was in population Kaona. Considering that ATChI (substrate) in increased concentrations inhibits normal AChE activity, it can be concluded that altered AChE affected the change in the populationorder. The testing of AChE in the presence of high concentrations of substrate showsthe portion of altered AChE is largest in population Ratari, and yet considerably smallerin Dobanovci, Futog and Kaona. The total AChE activity is in correlation with thedetermined resistance to carbamates.