Residual effects of TMOF-Bti formulations against 1^(st) instar Aedes aegypti Linnaeus larvae outside laboratory

Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus Kuala Lumpur.Methods:Twenty first instar Ae.aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried-leaf powder as their source of food.Combination of TMOF-Bti in rice husk formulation with the following weights viz 10,25,50 and 100 mg,respectively in duplicate was distributed in the buckets;while TMOF-Bti in wettable powder formulation each weighing viz 2,5,10 and 20 mg,respectively in duplicate was also placed in the buckets.The control buckets run in duplicate with 4 L of water and 20 first instar Ae.aegypti larvae.All buckets were covered with mosquito netting.Larval mortality was recorded after 24 hours and weekly for five weeks.A new batch of 20 1^(st) instar larvae Ae.aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder.The experiment was repeated for four times.Results:The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied.The TMOF(2%) + Bti(2%) had a good residual effect until the end of 3^(rd) week,TMOF(4%) + Bti(4%) until 4^(th) week,wettable powder TMOF(20%) + Bti(20%) until the third week.Condusions:From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control.

Bti微胶囊制剂防治蚊虫的研究

苏云金杆菌以色列变种（Ｂｔｉ）广泛应用于现场控制蚊幼虫，取得良好的杀灭效果。但由于现有剂型持效期短，限制了更大规模的应用，也给储存运输带来麻烦。本研究主要在室内评价了不同浓度Ｂｔｉ微胶囊制剂对中华按蚊、淡色库蚊和白纹伊蚊幼虫的效果及持效。结果表明，该种制剂有一定的漂浮性，在水内稳定性较好，具较长的持效期，１．２５ｐｐｍ浓度４周内对白纹伊蚊幼虫仍有较理想的杀灭效果。推荐防治中华按蚊、淡色库蚊和白纹伊蚊的需要剂量分别为０．２５、１．２５和０．０５ｐｐｍ，每２～３周施药１次。