Flufenoxuron, an acylurea insect growth regulator, alters development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) by modulating levels of chitin, soluble protein content, and HSP70 and p34 in the larval tissues

The effect of sublethal concentrations, 0.00141% (LC₂₀), 0.00251% (LC₃₀), and 0.0036% (LC₄₀) of a dispersible formulation of an acylurea insect growth regulator, flufenoxuron (Cascade) on certain biochemical parameters in the larvae of Tribolium castaneum was investigated. When neonates were fed on diet treated with sublethal concentrations for 24 h, it was observed that at all concentrations tested, there was a significant reduction in chitin content on the 15th day of development. Total soluble protein content at LC₂₀ and LC₃₀ decreased with increasing age of the larvae. At LC₂₀ and LC₄₀ concentrations there was a progressive increase in the protein: chitin ratio as a function of increase in age of the larvae. SDS-PAGE analysis of the larval tissue extracts indicated gross quantitative changes in some of the protein bands (MW 50-97 kDa). Western blot analysis revealed significant increase in the level of HSP70 in the extracts of larvae fed on LC₃₀ treated diet, on the 7th and 10th day of development in the decreasing order. Conversely, a significant decrease in the hyper-phosphorylated form of p34^cdc2 kinase due to flufenoxuron treatment indicating modulation of cell cycle regulation was observed. Thus, sublethal concentrations of flufenoxuron alter expression of developmentally regulated proteins, HSP70 and p34^cdc2 and chitin formation in a stage-specific manner thereby resulting developmental abnormalities in T. castaneum.     

稻田释放拟澳洲赤眼蜂防治一代二化螟研究

[目的]在越冬代二化螟发蛾盛期稻田人工释放拟澳洲赤眼蜂,考察寄生蜂对螟害的控制作用,据此研究水稻病虫害生物防治措施的效果,从而为水稻病虫绿色防控配套措施提供依据。[方法]试验设放蜂田、农民自防田和不防治对照田3个处理,对赤眼蜂寄生率和保苗效果进行统计分析。[结果]拟澳洲赤眼蜂释放区的一代二化螟卵块和卵粒平均校正寄生率分别为66.18%和15.94%,保苗效果为56.52%。[结论]于越冬代二化螟发蛾始盛期释放拟澳洲赤眼蜂对一代二化螟的危害有一定控制效果,可作为一代二化螟绿色防控措施进行推广应用。     

不同选择方法在单世代选择与多代选择间的差异

用个体选择法（ＩＤ）、家系选择法（Ｆ）和指数选择法（ＩＸ）三种选择方法，对赤拟谷盗２１日龄蛹重向上选择，以对比各方法间在进行一个世代选择和多个世代选择时有何不同。试验设两个重复，每个重复含有一个相同培育条件下的随机交配的对照组。蛹重经一代选择，试验结果表明，三种选择方法与对照组差异均为极显著（Ｐ＜０．０１），三种方法多重比较结果，除个体选择法和家系选择法间差异不显著外，其它组合对比均为差异极显著。当向上选择到第五个世代时，各选择方法均与对照差异极显著（Ｐ＜０．０１），各种选择方法间差异极显著。结论是无论一个世代选择，还是多代选择，均为指数选择法效果最好，但一世代选择所得反应排序为ＩＸ＞Ｆ＞ＩＤ，而选择到第五世代三种方法排序为ＩＸ＞ＩＤ＞Ｆ。     

赤拟谷盗乙酰胆碱酯酶生化及毒理学特性研究

为了阐明赤拟谷盗[Triboliumcastaneum(Herbst)]体内乙酰胆碱酯酶(AChE)在其各虫态间的变化关系,以期为该虫的综合治理提供一定的理论依据,本试验采用微量滴度酶标板法,分别对其10d龄和20d龄幼虫、蛹及成虫体内AChE的生化及毒理学特性进行了较为系统的研究。结果表明,赤拟谷盗各虫态AChE酶源蛋白含量、酶活力和比活力差异显著,酶源蛋白含量从低到高依次为:10d龄幼虫<20d龄幼虫<成虫<蛹;AChE活力和比活力依次为:成虫<蛹<10d龄幼虫<20d龄幼虫。酶动力学分析发现,AChE米氏常数Km值大小依次为:蛹<成虫<10d龄幼虫<20d龄幼虫,但成虫和蛹之间的差异不显著。此外,幼虫AChE的最大反应速度Vmax亦显著高于成虫和蛹。通过对幼虫AChE离体抑制作用测定表明,毒扁豆碱、马拉氧磷和西维因对20d龄幼虫的抑制中浓度I50均高于10d龄幼虫,说明20d龄幼虫体内的AChE对3种抑制剂的抑制作用更不敏感。     

植物芳香油配合气调对杂拟谷盗成虫致死率研究

采用5种植物芳香油,配合5％O_2+12％CO_2+83％N_2气调熏蒸杂拟谷盗 Tribolium confusum 成虫。结果表明,气调具有增强红桔油松节油及柠檬油的杀虫效果,对柠檬叶油的增强作用最为明显。在低 O_2环境中,低浓度的红桔油和松节油对杂拟谷盗成虫具有较强的熏杀作用。     

农户储粮害虫发生规律观察

农户储粮害虫以玉米象、麦蛾、书虱为主,以户计算的发生率为100%,锈赤扁谷盗、赤拟谷盗、米扁虫、谷蠹的发生率依次是20%、16.7%、16.7%、13.3%。随着仓温不断上升,4月上中旬开始见到玉米象、麦蛾成虫活动;7月中旬至8月中旬,仓温上升至30℃,经过3~4个月的发育、繁殖,玉米象、麦蛾虫口密度大,成虫活动频繁,并一直维持到9月下旬至11月中旬。气温为0~8℃的12月,也有玉米象、麦蛾的成虫活动。由于农户粮堆较小、天敌较多,因此,农户储粮害虫防治应以装具、清洁为主,以储粮防护剂为辅。     

枝孢属国内新记录种

枝孢属（ＣｌａｄｏｓｐｏｒｉｕｍＬｉｎｋ）的国内新记录种：紊乱枝孢（Ｃ．ｃｏｎｆｕｓｕｍＭａｔｓｕｓｈｉｍａ），标本采自云南绿春黄连山自然保护区亚热带常绿阔叶林内，生于死枝条。另有３个种生于未见报道的新寄主植物上，即生于茶梨（ＡｎｎｅｓｌｅａｆｒａｇｒａｎｓＷａｌｌ．）叶上的高枝孢［Ｃ．ｅｌａｔｕｍ（Ｈａｒｚ）Ｎａｎｎｆｅｌｄｔ］，莉竹（Ｂａｍ─ｂｕｓａｂｌｕｎｍｅａｎａＳｃｈｕｌｔ）叶上的尖孢枝孢（Ｃ．ｏｘｙｓｐｏｒｕｍＢｅｒｋｅｌｅｙ＆Ｃｕｒｔｉｓ）以及盈江南星（ＡｒｉｓａｍａｅｉｎｋｉｎｇｅｎｓｉｓＨ．Ｌｉ）肉穗花序和花序苞片上的枝状枝孢［Ｃ．ｃｌａｄｏｓｐｏｒｉｏｉｄｅｓ（Ｆｒｅｓｅｎｉｕｓ）ｄｅＶｒｉｃｓ］。文中对这些种分别作了描述并附图说明。     

4种植物精油对赤拟谷盗的控制作用研究

采用索氏提取法,以乙醚为提取溶剂提取大蒜、辣椒粉、柑桔皮、臭椿树皮的植物精油,研究其对赤拟谷盗的控制作用。结果表明:臭椿树皮、辣椒粉、大蒜3种植物精油对赤拟谷盗的成虫均有较强的驱避作用,柑桔皮精油对赤拟谷盗成虫具有一定的引诱作用;4种植物精油对赤拟谷盗成虫的触杀作用较弱;4种植物精油对赤拟谷盗当代种群均有一定的抑制作用,其作用大小顺序依次为柑桔皮精油>大蒜精油>臭椿树皮精油>辣椒粉精油;4种精油对赤拟谷盗成虫无明显的熏蒸作用,而对赤拟谷盗幼虫均有显著的熏蒸效果。     

Transovarial Effect of Novaluron on Tribolium castaneum (Coleoptera: Tenebrionidae) After Termination of Direct Contact

The insect growth regulator novaluron (Rimon 10 EC, Makhteshim-Agan Ltd, Israel) is used against many field pests on corn, vegetables, orchards, forests, and cotton plantations. Previously, we studied various effects of novaluron on stored grain pests. Termination in Tribolium castaneum (Herbst) eggs hatching after treating adults with novaluron and following restoration after adult transfer to untreated media was observed. The objective of this study was to investigate the restoration of T. castaneum egg hatch following transfer of adults from treated media to untreated favorable and unfavorable media. The time needed for hatching restoration of 50% of eggs laid by adults transferred from novaluron (1 ppm) treated flour to untreated flour (RT₅₀) was 2.7 d. RT₅₀ for those transferred to untreated wheat grain was 4.1 d. RT₉₀ in flour was 3.6 d, in grain—6.1 d. Varieties of RTs in grain and in flour with nonoverlapping confidence intervals indicate that RTs were significantly different. Delay of eggs hatching restoration for adults transferred from treated flour to unfavorable media (Petri dishes with limited amount of flour, lying of eggs not detected) was observed. RT₅₀ in flour was 2.1 d and RT₉₀—3.1 d, while RT₅₀ in the unfavorable media was 3.4 d and RT₉₀ 6.5 d. Delayed effect of egg hatching restoration after adult transfer to unfavorable media provides evidence of the significant role of insect physiological state in novaluron excretion and (or) degradation by T. castaneum females.