梨大蚜生物学特性及防治试验

梨大蚜是梨枝干上的一种重要害虫。四川已知有20多个县市有分布。该虫为全周期种类。以卵密集于梨树枝上越冬。翌年2月中旬开始孵化,若虫经四龄,以孤雌胎生方式繁殖,于雌若蚜三龄时,翅芽明显,并于4月下旬—5月上旬羽化为有翅干雌迁飞到夏寄主卧龙柳上(发生代数不详)。到9月下旬—10月上旬又由有翅性母迁回到梨枝上,以胎生方式繁殖,雄若蚜三龄时,翅茅明显,羽化后与雌蚜交配,产卵于枝上越冬。已发现该虫捕食性天敌4种,寄生性天敌2种。经室内、外药效试验表明:40%氧化乐果、80%敌敌畏乳油(1;1000倍液),10%除虫精乳油(1:500倍液);2.5%溴氰菊酯乳油(5—10)ppm 喷雾,均有较好的防治效果。

BIONOMICS OF PYROLACHUS PYRI (BUCKTON) AND ITS CONTROL

The pests pyrolachus pyri(Buckton)often cause serious damage to branches and trunks of pear.They pass over winter on pear branches as eggs which hatch into fundatrixes at the midst of February.The period of fundatrixconsists of 4 instages lasting about 34-40 days.Then adults appear and soon begin t~ reproduce parthenogenefically.The nymphs live on branches for about 25-34 days,and change to alate adults and migrate to their summer host-Salix dolia Schnid.By the end of September or early October the aphids usually migrate back to pear and reproduce both alate males and apteral female aphids. After mating,they deposit winter eggs on branches of pear.Three kinds of predator and one parasitic have been found.The result of this study shows that spraying the emulsion of 40% Omethoate(1:1000),80% Methoste(1:1000), 10% Ermetarin(1:500),2.5% Dices(5-10ppm)is effective control.