释放捕食螨对温室番茄上烟粉虱数量的影响

田间系统调查结果表明，棚室番茄植株上主要害虫为烟粉虱和蚜虫；巴氏钝绥螨和胡瓜钝绥螨均对烟粉虱虫口密度具有一定的抑制作用，其控害持效期50 d左右。2种捕食螨、2个释放密度对烟粉虱的控害效果无显著性差异，但巴氏钝绥螨控害作用略强于胡瓜钝绥螨。烟粉虱种群时间生态位宽度值为捕食螨释放区大于空白对照区，化防区最低，其值仅为0.5818；表明化防区目标害虫虫口数量在时间系列上分布的不均匀性，种群波动幅度较大，有暴发成灾的可能；而生防区害虫种群变化较稳定，不易成灾。烟粉虱种群空间生态位宽度在各处理区间无显著差异。

Predatory mites control Bemisia tabaci on totamato plants in greenhouse

A systematic field investigation showed that the major insect pests on tomato plants in greenhouse were Bemisia tabaci and aphid. It was observed that A. barkeri or A. cucumeris controlled Bemisia tabaci population and the controlling effect lasted for about 50 days, suggesting that repeat release of predatory mites in the temporal interval during the whole growing period could control Bemisia tabaci well. There was no significant difference between two predatory mites or two releasing densities, but the controlling effect of A. barkeri was slightly higher than that of A. cucumeris. The temporal niche breadth of B. tabaci with the treatment of releasing predatory mites was higher than that of the blank control and it was lowest in the chemical control plot with an average value of 0.5818. The results showed an obvious fluctuation in B. tabaci population and a risk of outbreak in the chemical control plots; however, in the biological control plots, the population of B. tabaci appeared to be stable. No significant difference in spatial niche breadths was observed among all treatments.