核桃根象生物学特性及防治试验

Biological Characteristics of Dyscerus juglaus and its control tests

核桃根象 (Dyscerusjuglaus)是四川省青川、平武等地危害核桃最为严重的害虫之一。该虫 2a一代 ,跨 3个年度 ,以幼虫蛀食核桃根颈部皮层致使大树衰弱乃至枯死。越冬成虫 3月中旬开始活动 ,6月开始产卵 ,至到 9月。卵期 10d左右。幼虫孵化蛀食核桃韧皮部危害 ,至当年 11月 ,以幼虫形态越冬。翌年 3月开始活动 ,4月化蛹 ,蛹期 2 0d～ 30d。成虫羽化后 ,当年可交配产部分卵 ,并以成虫在根颈部越冬。防治试验表明 。

Dyscerus juglaus is one of the worst pests which is severely harmful to walnut in Qingchuan and Pingwu counties of Sichuan Province. One generation of Dyscerus juglaus occurs per two years and will be found in three years. Larvae of Dyscerus juglaus chiefly feed on root crown cortices of walnut trees,thus causing the trees to weaken or die.The adults that have overwintered come to their new biological behavior phase in the middle of March,then mate,and lay eggs from June to September. As the adults die constantly,Dyscerus juglaus larvae hatch and eat into the bast of walnut trees until November,and come through the winter.They begin to eat in next March. Pupae can be found in April,and the period of pupae will last about 20 to 30 days. After eclosion, the adults begin to eat, mate and lay eggs. The adults like to come together to winter at the legs of walnut trees. By droping omethoate into the bast of walnut trees upon the distribution of larvae,Dyscerus juglaus can be relatively well controlled.