关键词: 马铃薯甲虫, 抗药性, 点滴法, 增效剂, 增效作用, 抗性机制

Abstract:

To understand the resistance levels and dynamics of Colorado potato beetle, Leptinotarsa decemlineata (Say) (CPB) in Xinjiang to conventional insecticides and offer the fundamental data for res0stance management, six overwintered CPB adult populations were collected from potato fields of Urumqi, Fukang, Changji, Altay, Nilka, and Tekes counties (cities) in northern Xinjiang Uygur autonomous region in China, and the first generation of 4th instar larvae were tested for resistance to fourteen conventional insecticides by topical application. And possible resistance mechanisms were investigated using three synergists, triphenyl phosphate (TPP), diethylmeleate (DEM), and piperonyl butoxide (PBO). The results showed that the Tekes field population was susceptible to several tested insecticides when compared to the baselines that have been documented. This population, therefore, was selected as a reference susceptible strain. Compared with the Tekes strain, Changji and Nilka populations had extremely high- to high- or moderate-level resistance to cyhalothrin (resistance ratio was 108.8- and 29.4-fold, respectively), deltamethrin (30- and 42.5-fold, respectively), carbofuran (17.6 and 10.1-fold, respectively), and carbosulfan (24.7- and 89.9-fold, respectively). Moreover, the Changji and Fukang beetles developed low- to moderate-level resistance to α-cypermethrin(8.9- and 13.0-fold, respectively). Synergism studies revealed that PBO had significant synergism to cyhalothrin in the Nilka population, and PBO, TPP and DEM exhibited significant synergism to carbofuran in the Changji population. These results suggest that enzymatic detoxification may be one of the resistance mechanisms to cyhalothrin and carbofuran for local populations in Xinjiang. Because the synergists do not completely eliminate CPB resistance, there are probably additional resistance mechanisms involved.

Key words: Colorado potato beetle, insecticide resistance, topical bioassay, synergist, synergism, resistance mechanism