松毛虫赤眼蜂防治玉米螟的效果及其影响因素

经10余年的大面积试验、示范．肯定了松毛虫赤眼蜂防治玉米螟的技果．放蜂区卵的校正寄生率达70％左右．效果优于化学防治。从夏玉米田寄生卵块中回收蜂种结果看出，在放蜂期12—15天内，橙毛虫赤眼蜂所占的比率为68．9％．证明释放的与收回的基本上仍是同一蜂种，但放蜂结束后蜂种结构发生了倒置变化。同时探明了松毛虫赤眼蜂的种型、放蜂时间、放蜂置、田间生态环境、玉米螟卵置等诸因素与防治效果的关系。

THE EFFECT AND INFLUENCE FACTORS ON THE USE OF TRICHOGRAMMA DENDROLIMI TO CONTROL OSTRINIA FURNACALIS

A fter large scale releasing Trich og ramma dend rolimito control Ostrinia furnacalis formore than 10 years. great effects were obtained.The corrected parasitic rates. which were gen-erally higher than those of chemical control and less than those of releasing Trichogramma ostrini-ae. reached 70% in the releasing fields. The percentage of T. d end rolimi recollected from theparasitlzed eggs of O. furnacalis in the summer planting corn fields was 68.9% within 12- 15days after releasing. but the recollected composition of Trichogramma spp. from the treated cornflelds changed reversely afterwords. Relationships between the effect and the influence factors. such as the type of T. dendrolimithe releasing time and releasing amount. the ecological condi-tions of the corn fields. the egg density of O. furnacalis etc. were discussed.