绿柳突瓣叶蜂生物学及防治

Biological characteristics and control of the sawfly,Nematus ruyanus

绿柳突瓣叶蜂(Nematus ruyanus Wei)是发生在甘肃天水柳树上的一种新害虫。严重危害旱柳、垂柳、金丝柳等多种柳树,1年发生6代,非越冬茧结于叶背,越冬茧结于1-5 cm表土中,以预蛹在越冬茧内越冬。幼虫食叶危害,每年3月下旬至10月下旬是该虫的猖獗危害期。用25%灭幼脲,1.8%阿维菌素乳油,40%氧乐果乳油2000倍液防治3龄前幼虫防效达95%以上;用2.5%溴氰菊酯乳油,3%高渗苯氧威乳油4000倍液喷冠防治3龄后大幼虫防效可达90%以上。

The sawfly, Nernatus ruyanus Wei, is a new pest of willow in Tianshui of Gansu It seriously damages the leaves of willow, Salix matsudana Koidz. and S. babylonica Linru and S. xaureo-pendula. Six generations of N. ruyanus occurred in Tianshui per year. Non-over-winter cocoons were produced on the back of the leaves, whereas over-winter cocoons occurred in 1-5 cm topsoils. They over-wintered as prepupae in their cocoons. The larvae occurred from the last ten days of March to the last ten days of October. The trees were seriously damaged during this period. The control efficacy reached over 95% with 2 000 × diluted solution of 25% chlorbenzuron and 1.8% abamectin EC and 40% omethoate EC before the third instar. The control efficacy was over 90% with 2 000× diluted solution of 2. 5% deltamethrin EC and 3% fenoxycarb EC after the third instar.