冬季防治红火蚁灌巢适宜时间的研究

Research on suitable time for controlling red imported fire ant(Solenopsis invicta Buren)in winter

为明确冬季防治红火蚁过程中自投放饵剂后至灌巢的间隔时间,在浙江省龙游县分别选择多蚁巢和少蚁巢发生区块,采取1m×1m的网格式诱饵布阵,调查在蚁丘表面投放饵剂前及投放饵剂后第2、4、7、16天时地表红火蚁数量。结果表明,在投放饵剂防治后第2天和第4天,诱捕的红火蚁数量较投放饵剂前明显下降;到投饵防治后第7天,平均每饵仅诱捕0.1~0.2头红火蚁,诱捕到红火蚁的饵占比不足5%,单饵诱到5头以上红火蚁的概率极低,此时离蚁巢相对较远的区域基本诱不到红火蚁。为避免残留红火蚁逃逸带来的分巢扩散风险,结合上述结论提出,在蚁丘地表投放饵剂后的第7天为冬季灌巢防治的适宜时间。

To determine the appropriate time for drenching insecticides towards red imported fire ant(RIFA),Solenopsis invicta Buren,nests after delivering toxic baits at the ant mound surface,we investigated the number of fire ants on the ground before and on the 2nd,4th,7th,and 16th day after bait delivery,respectively.This work was conducted in Longyou,Zhejiang at two invaded areas with high-and low-density nests(1 m×1 m net bait array).The results showed that on the 2nd and 4th day after baiting(0.73%hydramethylnon),the average number of RIFA captured per block decreased significantly.On the 7th day,only 0.1~0.2 RIFA individuals on average were captured at each point in both areas,and the proportion of baits with ants captured accounted for less than 5%.The probability of single bait trapping more than 5 ants was extremely low.At the same time,RIFA could be barely captured in relatively distant areas.In order to avoid the risk of nest spreading resulting from the escape of residual red imported fire ants,it was concluded that,in winter,seven days after bait delivery is the appropriate time to drench insecticides for RIFA control.