不同发育虫态扁谷盗属对S-烯虫脂耐受性研究

扁谷盗属是一类世界性重要的储藏物害虫。目前由于抗药性、可用技术广谱性和成本较高等问题,使得该类虫害的防治受到严重的挑战。针对杀虫剂抗药性问题,我们积极采取了各种措施包括多样化杀虫剂方式,杀虫剂组合如保幼激素类似物(JHA)与其他药剂复配。保幼激素类似物(JHA),如s-烯虫酯,具有很好的安全性和对多种仓储害虫有效性的特点。了解影响可替代技术效果的关键因素才能进行有效的防治管理。此外,了解害虫所有发育阶段的耐药性表达非常重要,因为药剂应用环境中所有虫态都存在。我们测定了扁谷盗属不同虫态及其F1种群对s-烯虫酯的耐受性。从发育阶段来看,成虫耐受性最高,其次是卵,然后是幼虫,其耐受性与F1代中的蛹大致相同。通过比较不同虫种的结果表明,最敏感的是长角扁谷盗,而耐受性最高的是土耳其扁谷盗。当浓度达到30mg/L及以上,锈赤扁谷盗和长角扁谷盗孵化率均小于50%,而土耳其扁谷盗需达到80mg/L时孵化率才低于50%。在幼虫期,仅需施用5 ppm s-烯虫酯,三个扁谷盗虫种死亡率都超过50%。在试验期间,s-烯虫酯并未完全抑制扁谷盗后代的产生,但即使在0.5 ppm浓度下,也会导致所有扁谷盗属的成虫显著减少。本研究这些结论可以得出,s-烯虫酯对这三个虫种非常有效,可作为储粮害虫综合防治的潜在手段。

Relative tolerance to S-methoprene in life stages of the Cryptolestes species

Cryptolestes species are serious cosmopolitan pests of stored products. Current pest control options are severely constrained by high prevalence of insecticide resistance and availability and relatively high costs of alternative interventions. Among various measures to counter the drawbacks of insecticide resistance include efforts to diversify the modes of action of insecticides with residual applications of combinations of insecticides, which include a juvenile hormone analog (JHA). JHAs, such as methoprene, have a desirable safety profile and are effective against a variety of indoor pests. Effective management requires knowledge of key factors driving the rate of selection. Moreover, it is important to understand the expression of resistance in all life stages as all stages are subjected to selection during application. We determined the relative tolerance to s-Methoprene in all life stages of Cryptolestes parental strains and their F1 progeny. In developmental stages, relative tolerance was highest in adults followed by eggs, then larvae which had about the same tolerance as pupae in the F1 progeny. Results regarding the comparative effect of different species showed that most susceptible in Cryptolestes pusillus and highest tolerance in Cryptolestes turcicus. Numbers of egg hatching were less than 50% for Cryptolestes ferrugineus and C. pusillus at above 30mg/L, but only for C. turcicus at 80mg/L. In case of larvae the mortality was more than 50% for all species where s-Methoprene was applied at above 5ppm. Methoprene did not completely suppress progeny production during the test period, but did cause a significant reduction in adult progeny in all Cryptolestes species at the application rates, even at 0.5 ppm. From these results, it is concluded that the applications of s-Methoprene have proved to be very effective against three species examined in the present study. It should be considered as potential components in IPM of stored grains insect pests.