辽宁地区韭菜根蛆发生与为害规律

为明确辽宁地区韭菜田根蛆发生种类及优势种的消长动态,于2014-2017年分别采用黄色水盆诱集和挖根的方法对根蛆成虫和幼虫的发生和为害规律进行了系统调查研究。结果表明,辽宁韭菜田根蛆主要有韭菜迟眼蕈蚊Bradysia odoriphaga Yang et Zhang和食用菌异迟眼蕈蚊Bradysia difformis Frey,二者常常混合发生。北镇地区优势种为韭菜迟眼蕈蚊,年发生7~8代,其中冬季温室期发生3~4代。初冬扣棚后根蛆为害期与冬韭生产期高度重合。沈阳东陵地区优势种为食用菌异迟眼蕈蚊,其在露地韭菜上年发生5代。根蛆在田间呈聚集分布,聚集程度随种群密度的增大而升高。施用有机肥可显著降低根蛆的为害程度。根蛆以3龄幼虫在大葱上越冬。辽宁地区根蛆的发生规律呈现冬季发生重,春、秋季略轻发生,夏季基本不发生的特点。

Regularity of outbreak and infestation features of Chinese leekroot maggot in Liaoning

To clarify the dominant pest species and occurrence regularity of Chinese leek root maggot in the leek fields of Liaoning Province, the occurrence of adults and larvae were investigated systematically by the earth yellow basins trapping and digging methods in the trial fields from 2014 to 2017. The results showed that Bradysia odoriphaga Yang et Zhang and B.difformis Frey mixed occurred in Liaoning Province. The B.odoriphaga was the dominant species in Beizhen and occurred seven to eight generations in chive fields annually, including three or four generations in greenhouses in winter. The infestation period of root maggot was highly consistent with the leek growing season in winter. The dominant species in Dongling, Shenyang was B.difformis, with five generations per year in open fields. Except the infestation in early winter after sheltering with plastic film, spring and autumn chives are also damaged by root maggot at different extent. The larvae showed aggregated distribution in field and the aggregation degree increased with the increase of population density. Organic fertilizer significantly depressed the injury level, and the survey showed that root maggot overwinter on Allium fistulosum with 3rd instar larva. It is concluded that the root maggot severely occurs in winter shelter, while less occurs in spring and autumn, and hardly occurs in summer.