尖翅小卷蛾的生物学特性

尖翅小卷蛾［Bactra lanceolana (Hübner)］是席草上的重要害虫,2004-2007年对浙南地区尖翅小卷蛾的生物学特性进行了系统研究。结果表明,尖翅小卷蛾越冬代成虫初见4月中旬初前后,全年发生7~8代,本田期发生4代,以第2代虫量最高,危害损失最重,其次是第3代和第1代,世代重叠,以幼虫在席草苗内越冬。成虫多在夜晚活动,有较强趋光性,但飞翔能力弱;停在草茎上,多数头朝下,尾朝上;雌雄性比1∶1.2,寿命长短与温度、湿度、雌雄性别等关系密切;成虫一般在原田活动,羽化、产卵多在晚上,以夜晚24:00前居多;羽化后当晚交尾,产卵前期多数1 d;卵粒大多产在粗壮植株中下部位、席草茎的凹槽上,自上而下产卵,亦有产在叶鞘上;卵一般在上午孵化,其孵化时间、孵化率高低、卵历期长短与温度、湿度有关。幼虫侵入、化蛹部位多在地面茎基部,中高龄幼虫还有转株为害的习性。     

Suppression ofbactra venosana,a potential natural enemy ofcyperus rotundus,bytrichogrammatoidea bactrae in Bangalore,India

Bactra venosana Zeller (Lepidoptera: Tortricidae) is the predominant natural enemy ofCyperus rotundas L. in Bangalore, India. Although the insect was found to have potential, it was incapable of suppressing the weed due to low incidence. Laboratory studies involving field-collected insect stages revealed that heavy parasitism of eggs byTrichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae) was the most important mortality factor suppressing its potentiality.