韭蛆,在北方普遍发生,棚室和露地韭菜均可受害。幼虫钻食韭菜地下部分,轻者地上叶片瘦弱、枯黄、萎蔫断叶,重者成墩死亡。幼虫常群集在鳞茎(俗称“葫芦”)里或钻蛀假茎中,引起腐烂,可造成整畦毁种。连茬地块蛆害严重时则可毁棚,损失极大。 1.生活习性 在华北地区1年发生4～6代,世代重叠。以幼虫在韭根周围3～4厘米土中或鳞茎内休眠过冬。3月份大棚韭菜萌发时,幼虫开始活动取食。3月下旬至5月中旬大部分越冬幼虫移向地表1～2厘米处化蛹,4月初至5月中旬羽化为成虫,并交尾产卵。从4月中旬起田间各虫态均有,4～5月是棚栽和露地韭菜危害盛期。7～9月由于 Leek maggots, commonly occur in the north, sheds and open leeks can suffer. Drilling larvae underground parts of leeks, the light leaves on the ground thin, yellow, wilted leaves, severe death into pier. Larvae often cluster in the bulbs (commonly known as “gourd”) or moth-eaten stems, causing decay, can cause devastating species. Stubble block maggot damage can be destroyed when the block shed, great loss. 1. Habits In North China 1 year occurred 4 to 6 generations, generations overlap. To larvae in allium around 3 to 4 cm soil or bulb dormancy winter. March chives germination, the larvae began to eat activities. Most of the overwintering larvae migrated to the surface of 1-2 cm from the end of March to the middle of May to pupae, and the adults became adults in early April and mid-May. Since mid April from the insect state are all in the field, 4 to 5 months is shed and exposed chives harmful period. 7 to September due