Potential of parasitoids to control populations of the weevil Ceutorhynchus obstrictus (Marsham) on winter oilseed rape

Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae) is a major pest of oilseed rape in Europe and North America. The last decade has seen growing interest in the occurrence, importance and efficiacy of its parasitoids as biocontrol agents. The infestation of pods by C. obstrictus larvae and their parasitism rates were assessed in a total of nine commercially-grown crops and fifteen experimental plots of winter oilseed rape in 2004–2007. Pod samples were collected at the pod maturation stage and incubated in emergence traps. Emerged larvae, their exit holes and parasitoids were counted and identified; the percentage of infested pods and parasitism rates were calculated. Pod infestation by larvae increased continuously over the study period. The parasitism level was lowest in 2005 and increased thereafter up to 96%. The most abundant parasitoid was Trichomalus perfectus (Walker), but Mesopolobus morys (Walker) and Stenomalina gracilis (Walker) (Hymenoptera: Pteromalidae) were also reared from host larvae. This study showed that naturally-occurring ectoparasitoids of C. obstrictus were capable of becoming established as viable populations and have the potential to contribute to biological control of C. obstrictus.     

采用喷烟技术防治栎黄掌舟蛾的效果研究

[目的]探寻既不影响生态环境又能有效控制栎黄掌舟蛾[Phalera assimilis(Bremer et Grey)]虫口数量增长的有效方法与措施.[方法]运用喷烟技术在闽粤栲林分中研究了1％苦参碱可溶性液剂(喷烟型)、1.2％烟碱·苦参碱乳油和1.8％阿维菌素乳油对栎黄掌舟蛾幼虫的防治效果.[结果]1.2％烟碱·苦参碱乳油、1％苦参碱可溶性液剂及1.8％阿维菌素乳油对栎黄掌舟蛾3～4龄幼虫药后4d的防治效果都达到85％以上.[结论]供试3种药剂可作为防治栎黄掌舟蛾幼虫的药剂.     

栎掌舟蛾生物学特性及其防治

栎掌舟蛾在吉林地区1a1代，以卵越冬，主要危害栎树和榆树。用20％速灭杀丁乳油、5％来福灵乳油和2．5％敌杀死乳油灭虫效果达100％。     

蔷薇斑蛾的特征特性及防治

介绍了蔷薇植物上发生为害较为突出的一个新害虫种类——蔷薇斑蛾(Illiberis assimilis Jordan),包括其形态特征、为害特点、生物学特性及其防治措施.     

Impacts of abiotic factors on population fluctuation of insect fauna of Vigna radiata and Tetranychus urticae Koch in Sindh, Pakistan

Effect of temperature and relative humidity on population dynamics of insect pests of mung bean was studied during mung bean growing season of 2005. Insect pests included thrips (Thrips tabaci Lind.) and field cricket (Gryllus assimilis) and one arachnid pest mite (Tetranychus urticae Koch). Results revealed that the maximum population of thrips and mites was observed on August 23, 2005 with 1.537±0.031 per leaf and July 6, 2005 with 3.271±0.09 per leaf, respectively. The population of field cricket differed significantly during crop season and reached its peak during the initial stage of crop growth on June 14, 2005, i.e., 0.873±0.014 per plant at the temperature and relative humidity of 32°C and 54%, respectively, while the minimum population was noted on August, i.e., 0.710±0.010 per plant. Present studies conclusively document the correlation of weather factors and insect pest population. Temperature had a negative and significant correlation with thrips (r = −0.860) and a positive and significant correlation with mites (r = 0.606) and field cricket (r = 0.439). However, the relative humidity displayed a positive and significant correlation with thrips (r = 0.569), a negative non-significant correlation with mites (r = −0.313), and a significant negative correlation with field cricket (r = −0.770).