麦双尾蚜及其天敌在春小麦和野生寄主上的种群动态

POPULATION DYNAMICS OF THE RUSSIAN WHEAT APHID AND ITS NATURAL ENEMIES ON SPRING WHEAT AND WILD HOSTS

在塔城麦田调查发现， 麦双尾蚜Ｄｉｕｒａｐｈｉｓ ｎｏｘｉａ （ Ｍｏｒｄｖｉｌｋｏ） 在春小麦和野生寄主上的百株蚜量从大到小依次为春小麦、黑麦和野燕麦， 在春小麦上最早出现高峰期。在春小麦上， 瓢虫类数量最多达到５１６ 头／ 百株， 菜蚜茧蜂Ｄｉａｅｒｅｔｉｅｌｌａ ｒａｐａｅ 和白足蚜小蜂Ａｐｈｅｌｉｎｕｓ ａｌｂｉｐｏｄｕｓ 的最高寄生率分别达到３１－６ ％ 和１２－９％ 。在黑麦上， 麦双尾蚜主要被白足蚜小蜂寄生， 最高寄生率达到４２－９ ％ ， 斑腹蝇幼虫Ｌｅｕｃｏｐｉｓａｎｎｕｌｉｐｅｓ 最高达到１６ 头／ 百株。在野燕麦上， 白足蚜小蜂和菜蚜茧蜂最高寄生率分别达到６２－３ ％ 和３１－８ ％ 。瓢虫和菜蚜茧蜂发生较早， 白足蚜小蜂和斑腹蝇发生时间相对较晚。

Densities of the Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko),and its natural enemies were surveyed at 5～10 day intervals in the summer of 1996 on spring wheat and wild hosts in Tacheng,Xinjiang Uygur Autonomous Region,China. The aphid was more abundant on spring wheat than on secale, Secale cereale L. and wild oat, Avena fatua L. and reached its peaks earlier on spring wheat and oat than on secale. Number of coccinellids in spring wheat field increased up to 516 per 100 tillers. The parasitized rates of D. noxia by Diaeretiella rapae and Aphelinus albipodus were up to 31 6% and 12 9% respectively. On the secale plants,42 9% of the aphids were parasitized by A. albipodus, and the predator Leucopis annulipes found as up to 16 larvae per 100 tillers. On the oat plants,62 3% and 31 8% of the aphids were parasitized by D. rapae and A.albipodus respectively. D. rapae and most coccinellids appeared in earlier stage of RWA infestation,whereas A. albipodus and L. annulipes occurred lately.