Combined treatments of spinosad and chlorpyrifos-methyl for management of resistant psocid pests (Psocoptera: Liposcelididae) of stored grain

The combined efficacy of spinosad and chlorpyrifos-methyl was determined against four storage psocid pests belonging to genus Liposcelis. This research was undertaken because of the increasing importance of these psocids in stored grain and the problem of finding grain protectants to control resistant strains. Firstly, mortality and reproduction were determined for adults exposed to wheat freshly treated with either spinosad (0.5 and 1 mg kg(-1)) or chlorpyrifos-methyl (2.5, 5 and 10 mg kg(-1)) or combinations of spinosad and chlorpyrifos-methyl at 30 degrees C and 70% RH. There were significant effects of application rate of spinosad and chlorpyrifos-methyl, both individually and in combination, on adult mortality and progeny reduction of all four psocids. Liposcelis bostrychophila Badonnel and L. decolor (Pearman) responded similarly, with incomplete control of adults and progeny at both doses of spinosad but complete control in all chlorpyrifos-methyl and combined treatments. In L. entomophila (Enderlein) and L. paeta Pearman, however, complete control of adults and progeny was only achieved in the combined treatments, with the exception of spinosad 0.5 mg kg(-1) plus chlorpyrifos-methyl 2.5 mg kg(-1) against L. entomophila. Next, combinations of spinosad (0.5 and 1 mg kg(-1)) and chlorpyrifos-methyl (2.5, 5 and 10 mg kg(-1)) in bioassays after 0, 1.5 and 3 months storage of treated wheat were evaluated. The best treatment was 1 mg kg(-1) of spinosad plus 10 mg kg(-1) of chlorpyrifos-methyl, providing up to 3 months of protection against infestations of all four Liposcelis spp. on wheat.     

嗜卷书虱和嗜虫书虱的研究进展

嗜卷书虱和嗜虫书虱同属于啮目、书虱科、书虱属,亲缘关系极近,在全世界广泛分布,常混合发生在储藏物中,大量发生时可造成严重的经济危害,在我国,已经上升为“双低(低氧、低药剂)”和“三低(低氧、低药剂、低温)”气调储粮中的害虫优势种群。本文对两书虱的危害性、生物学、生态学特性、生理生化及遗传稳定性、防治及对药剂和气调的抗性等方面的研究概况进行了综述,以期引起人们对该两种微小但危害日益严重的储粮害虫的充分重视。     

储粮环境中书虱猖獗发生的因子分析

近年来书虱逐渐成为储藏物环境中的优势害虫种群，严重危害储粮的品质．已引起粮食储运、植物检疫和卫生部门的高度重视。本文介绍了书虱的主要类群及生物学特性，指出其大量发生的危害性，系统讨论了在储粮环境中书虱猖獗发生的因子，指出书虱的生殖潜力及高温和高温等是有利于书虱种群发展的生态因子，而在储粮过程中采用的不恰当的熏蒸和气调处理措施则是导致书虱暴发的主要原因。     

嗜卷书虱的检疫及其近缘种的检索

[目的]首都机场检疫局从入境旅客携带物上截获一种啮虫目昆虫,经中国农业大学植物检疫与入侵生物学实验室鉴定为嗜卷书虱Li poscelis bostrychophila Badonnel,1931;[方法]对该虫的有关文献的翻译和整理,对该虫进行了全面的介绍;[结果]详细介绍了其分类地位、地理分布、生物学特性、传播情况和潜在危害等,并提供了10个近缘种的检索表;基于以往截获记录、口岸鉴定及实际防治中存在的困难,讨论了仓储啮虫的检疫意义;[结论]鉴于仓储啮虫危害特点及其检疫意义,口岸应引起足够的重视,加强检疫工作,严防该类害虫的传入.     

Characterization of the Purified Glutathione S-transferases from Two Psocids Liposcelis bostrychophila and L.entomophila

Glutathione S-transferases（GSTs） from Liposcelis bostrychophila Badonnel and L.entomophila（Enderlein）（Psocoptera：Liposcelididae） were purified by glutathione-agarose affinity chromatography,and characterized subsequently by their Michaelis-Menten kinetics toward the artificial substrates 1-chloro-2,4-dinitrobenzene（CDNB） and reduced glutathione（GSH）,respectively.The specific activity of the purified GST toward CDNB was 2.3-fold higher in L.bostrychophila than in L.entomophila.Though the specific activities of purified enzymes varied between the two species,the purification yields were similar.SDS-PAGE revealed one band at 23 kDa for both the species.GSTs of L.entomophila exhibited higher Michaelis-Menten constants（Km） but lower maximal velocity（Vmax） values than those of L.bostrychophila.The optimum pH for CDNB conjugation of L.bostrychophila and L.entomophila GSTs was 7.0 and 7.5,and optimum temperature was 35 and 40°C,respectively.Inhibition kinetics showed that cibacron blue,curcumin,bromosulfalein,ethacrynic acid,and carbosulfan had excellent inhibitory effects on GSTs in both species,but the inhibitory effects of beta-cypermethrin,fenpropathrin,tetraethylthiuram disulfide,and diethyl maleate were not significant.     

磷化氢对3种储粮书虱致死浓度与时间的比较研究

比较测定了磷化氢对嗜卷书虱Liposcelis bostrychophila(Pearman)、嗜虫书虱L.entomophila(Enderlein)和小眼书虱L.paeta(Pearman)等3种储粮书虱的毒力,并研究了在室温条件下磷化氢浓度分别为100、200、300、400和500mL/m3的完全致死时间。结果表明:磷化氢对嗜卷书虱、小眼书虱和嗜虫书虱的LD50值(95%置信限)分别为0.0039(0.0038～0.0042)、0.0804(0.0750～0.0887)和0.0815(0.0815～0.0892)mg/L,嗜虫书虱对磷化氢的耐受力比嗜卷书虱高20多倍。在试验浓度下第7d可全部致死嗜卷书虱,100mL/m3的浓度完全致死小眼书虱和嗜虫书虱则需22d多;200mL/m3完全致死小眼书虱和嗜虫书虱的时间约为19d,300mL/m3浓度完全致死小眼书虱和嗜虫书虱的时间在13d和16d,400mL/m3及以上浓度完全致死小眼书虱在7d以内,完全致死嗜虫书虱仍需13d。500mL/m3的浓度完全致死嗜虫书虱仅缩短到10d。采用磷化氢熏蒸书虱在100～500mL/m3的浓度范围内,提高浓度可以使完全致死书虱的时间明显缩短。     

Potential of imidacloprid to control four species of psocids (Psocoptera: Liposcelididae) infesting stored grain

The effectiveness of the neonicotinoid insecticide imidacloprid was evaluated against four psocid pests of stored grain. This research was undertaken because of the growing importance of psocids in stored grain and the need to identify methods for their control. The mortality and reproduction of adults of Liposcelis bostrychophila Badonnel, L. entomophila (Enderlein), L. decolor (Pearman) and L. paeta Pearman in wheat treated with imidacloprid were determined. There were five application rates (0.5, 1, 2, 5 and 10 mg AI kg(-1) grain) and an untreated control. There were significant effects of application rate on both adult mortality and reproduction for all four species, but the effect of imidacloprid was sometimes more pronounced on reproduction. Imidacloprid was most effective against L. bostrychophila, with 100% adult mortality after 7 d at 5 mg AI kg(-1), 14 d at 2 mg AI kg(-1) and 28 d at 0.5 and 1 mg AI kg(-1). No live progeny were produced at 2 mg AI kg(-1). For L. decolor, there was 100% adult mortality after 28 d at 10 mg AI kg(-1) and no live progeny were produced at 2 mg AI kg(-1). For L. entomophila, there was 100% adult mortality after 14 d at 10 mg AI kg(-1) and 28 d at 2 and 5 mg AI kg(-1). No live progeny were produced at 10 mg AI kg(-1). At 10 mg AI kg(-1) there was 100% mortality of L. paeta adults after 28 d exposure and no live progeny developed. Because reproduction at some application rates occurred only in the first 14 d of exposure, it is concluded that the application rate leading to population extinction was 1 mg AI kg(-1) for L. bostrychophila, 2 mg AI kg(-1) for L. decolor and L. entomophila and 5 mg AI kg(-1) for L. paeta. This study shows that imidacloprid has potential as a grain protectant to control all four Liposcelis species in stored grain.