Abstract: Acanthoscelides obtectus (Say) is the most destructive insect for leguminous crops around the world. Food-grade inert dust is an efficient protective agent to control A. obtectus. Lethal concentrations of food-grade inert dust can cause mortality of A. obtectus. Whereas, the concentrations of inert dust may have differences in different position of the grain by mixing inert dust with the surface of grain in horizontal warehouse. It may cause the stored grain pests to be exposed to different amounts of drug. Therefore, it is of important practical guiding significance to study the effect of low inert dust concentration on the development and reproduction of A. obtectus. This paper studied the changes of its developmental duration, survival rate and fecundity after Phaseolus vulgaris treated with low concentrations of food-grade inert dust. The results showed that when A. obtectus was exposed to LC10, LC20 and LC50 of food-grade inert dust, both the hatchability and larval-pupal survival rates decreased, and there were significant differences on the larval-pupal survival rates compared with the control group (P＜0.05). Compared with the control, the adult longevity was shortened by 7.49 d, 8.74 d and 6.65 d, respectively, and the fecundity of single female was decreased significantly by 14.55 eggs, 11.75 eggs and 15.40 eggs, respectively. The developmental duration of different stages were affected after treating with LC10, LC20 and LC50 of food-grade inert dust. According to the survival rate and fecundity of A. obtectus treated by different concentrations of food-grade inert dust, the life table of fecundity was constructed. For LC10, LC20 and LC50 treatments the intrinsic rate of increase (rm) decreased by 11.11%, 22.22% and 44.44%, respectively, and net reproductive rate (R0) decreased by 25.77%, 37.37% and 69.11%, respectively, whereas the mean generation time (T) and population doubling time (t) were delayed. These results showed that low concentration of food-grade inert dust could suppress the population growth of A.obtectus.

Key words: Acanthoscelides obtectus (Say), food-grade inert dust, low concentration, life table, population parameter

摘要： 菜豆象是多种豆类作物的重要害虫，食品级惰性粉作为有效防治菜豆象的防护剂，可以在致死浓度下直接杀死菜豆象。但在实仓中粮面的拌和处理可能导致粮堆中不同部位惰性粉浓度存在差异，造成储粮害虫个体间接触药量不同，所以研究低浓度惰性粉对菜豆象发育和繁殖的影响具有重要的实践指导意义。研究以低浓度(LC10、LC20和LC50)的食品级惰性粉处理菜豆后供菜豆象取食，考察了受胁迫后试虫发育历期、存活率、繁殖力的变化。结果表明：经低浓度食品级惰性粉处理后，菜豆象卵孵化率和幼虫-蛹存活率均降低，且幼虫-蛹存活率与对照间存在显著差异(P＜0.05)；成虫寿命分别缩短了7.49 d、8.74 d和6.65 d；单雌产卵量分别减少了14.55粒、11.75粒和15.40粒。惰性粉处理对菜豆象各虫态发育历期也有一定影响。根据不同浓度处理后菜豆象各发育阶段的存活率和成虫的繁殖力，组建了生殖力生命表，发现各处理组种群内禀增长率(rm)分别降低了11.11%、22.22%和44.44%，净增殖率(R0)分别降低了25.77%、37.37%和69.11%，而世代平均历期(T)和种群加倍时间(t)均延长。表明低浓度的食品级惰性粉可在一定程度上抑制菜豆象种群增长。

关键词: 菜豆象, 食品级惰性粉, 低浓度, 生命表, 种群参数