Determination of beta-cyfluthrin resistance in cigarette beetle Lasioderma serricorne (F.) (Coleoptera: Anobiidae) and evaluation of control effect of alternating imidacloprid in field trials

Spray toxicity bioassays were conducted to study the toxicity of beta-cyfluthrin and imidacloprid against L. serricorne in laboratory. Preliminary trials were carried out to determine appropriate ranges of testing concentration. In laboratory, at 27 ℃, spray tower was placed on a flat marble tabletop to ensure that the bottom of spray tower fitted perfectly with tabletop to prevent insects from escaping. After slowly introducing 20 adults to tower bottom from tower mouth, 0.5 mL liquid was sprayed into spray chamber at tower mouth with a hand-held ultra-low volume atomizer gun, at a distance of 35 cm. Tower mouth was covered with a glass cap immediately (not sealed). Dead individuals were documented 2 and 24 hours after treatment under dark conditions. An adult was considered dead if its appendages did not move when prodded with a hair brush. Probit analysis was used for analyzing the bioassay data to estimateLC_50. Field trials were carried out in the cigarette manufacturing area of Hefei Cigarette Manufacturing Factory in Hefei, Anhui, China. Before test, five sections worked normally and were cleaned normally following written sanitation procedures. Beta-cyfluthrin were sprayed in the space of five sections. Seven weeks later, imidacloprid aerosols were sprayed in the same space of five sections. Pheromone traps were used to monitor the number of insects captured. The number and hanging height of the pheromone trap in each section were based on CORESTA. Traps were placed on steel nail of the wall or column and marked for position. The numbers of L. serricorne caught by traps were recorded once a week, and traps were replaced every 30 days.