福建柑桔大灰象虫(Sympiezomia lewisi Roel.)生活习性及防治初步研究

大灰象虫是福建省柑桔类果树的重要害虫之一,此虫在福州、閩侯地区,一年发生一代,少数二年完成一代。以成虫及幼虫在土中越冬。越冬成虫于3月底开始出土活动,取食新梢嫩叶及幼果。4月中旬为发生盛期并开始产卵,产卵期长达69—111天。卵期在4—6月間为7—12天,7—8月間为5—6天。4月下旬幼虫开始孵化,7月中旬以前孵出的幼虫,当年10月底开始羽化,羽化成虫在蛹室中越冬,翌年春暖出土;7月下旬以后孵出的幼虫,当年职幼虫在土室内越冬,幼虫期长372—400天,直到第二年9—10月間才化蛹、羽化,并以成虫越冬,第三年春暖出土。成虫食性复杂,不同食料植物对其寿命、产卵量、产卵期有很大影响。生活在桃树上成虫寿命最长,产卵数量也最多。防治方法,采取胶环捕杀或人工震落捕杀成虫收效很大。药剂方面,可噴射50％敌百虫400倍液或6％可湿性六六六及25％DDT乳剂混合液(1:1:200)效果甚好。

BIONOMICS OF SYMPIEZOMIA LEWISI ROELOFS IN FUKIEN PROVINCE

In recent years, Sympiezomia lewisi Roelofs has become one of the most important citrus pests in Fukien and caused tremendous losses to the local citrus production. The present paper gives a report on the biological studies of this pest carried out in the Foochow, Minghow districts during 1961-1963. The weevil has one generation per year, and in a few cases one generation may extend to two years. They overwinter in the form of adults or larvae underground. The overwintering adults come out from the earth in the end of March and become enormous in mid-April. The adults devour the fresh tender leaves and fruit pulp as food, Females start to lay eggs in mid-April, the oviposition period lasts 69-111 days. Eggs are laid on the margin between two overlapping leaves, The incubation period lasts 7-12 days in April, May and June and 5-6 days in July and August. The newly hatched larvae enter into the ground and live there for a period of 88-157 days. Pupation of the mature larvae takes place from the end of September to October in pupal chambers at a depth of 10-45 cm. beneath the soil surface. Adult emergence takes place over a period of 18-24 days. The emerged adults, however, stay still in the pupal chambers to overwinter and come out from the earth next spring. It has been found that the duration of one generation varies with the time of hatching. Larvae hatched before mid-July have a chance to become adults in October, while those hatched after mid-July have to ovewinter in the earth and will not become pupae until September to October the next year. In this case, which is rare, it requires 2 years for the completion of one generation.