论文部分内容阅读
苎麻天牛(Paraglenea fortunei Saunders)近年在局部地方为害棉花,1989年6月在南县鸟咀乡安乐村的300多亩棉田发生,一般每亩有苎麻天牛5000-15000头,有100多亩为害严重,虫多的每亩达到20000多头。为害株率25-40％,死苗率10-20％。 此虫1年发生1代,越冬幼虫4月上中旬化蛹,5月中下旬羽化。5月底开始迁入棉田,6月上中旬为盛发期。成虫以早晚或阴天群集在棉田活动与为害,睛天中午停留在棉叶背面和田边杂草丛中歇息。成虫取食棉苗叶柄、嫩茎,咬断嫩头。使棉花的叶片掉落,主茎折断,嫩头枯死。为害重的棉株成为光杆,造成棉花严重减产。凡靠近麻地,棉苗生长嫩绿旺盛的棉田为害最重。 近年来忽视了对天牛的防治,虫口密度累积增多:加之是麻农挖麻种棉,形成了棉麻插花种植,给天牛的迁飞为害创造了有利的环境条件:苎麻天牛羽化高峰期,正值头麻收
In recent years, the ramie days (Paraglenea fortunei Saunders) harbored cotton in local areas. In June 1989, it occurred in 300 acres of cotton fields in Anle Village, Bird’s Nest Township, Nanxian County. Generally, there are 5000-15000 heads of ramie per hectare and 100 mu Serious damage, pests and more than 20,000 acres per head. Damaged plants rate of 25-40%, dead seedlings rate of 10-20%. This worm occurs 1 generation a year, overwintering larvae on the mid-April pupation, emergence in mid to late May. The end of May began to move into the cotton field, in mid-June for the Shengfa period. Adults to early or late cloudy or cloudy activities and damage in the cotton field, eyes stay at noon on the back of cotton leaves and Tanabe weeds rest. Adults take cotton seedling petiole, tender stem, snapped off tender head. So that the leaves of cotton fall, the main stem broken, tender head dead. Damaged cotton plants became polished poles, resulting in serious cuts in cotton production. Where close to Ma Dian, cotton seedlings grow the most vigorous green verdant damage. In recent years, neglect of the control of the beetles, insect population density increased: In addition, hemp farming digging cotton, cotton and cotton formed a flower planting, to the migration of pests to create favorable environmental conditions: ramie peak feather peak Period, is the first cropped head