大乐中学从本地农业生产的实际需要出发,结合教学积极开展科研活动,对当地农业生产的发展起了一定的促进作用。进行生物防治试验。一九七五年上期,他们从湖南农学院引进松毛虫赤眼蜂种,因陋就简进行人工繁殖,共繁蜂一百九十二只,放蜂五十亩,卵寄生率达百分之八十八,卷叶下降 Dale Middle School started from the actual needs of local agricultural production and actively carried out scientific research activities in conjunction with teaching, which played a role in promoting the development of local agricultural production. Conduct biological control tests. In the first half of 1975, they introduced the pine caterpillar Trichogramma species from the Hunan Agricultural College, and they artificially propagated the quail because of the baboons. There were a total of 192 live bees, 50 mus of bees, and an egg parasite rate of 80 percent. Eight, leaf curling