Screening of bacteria isolated from the environment for the capability to control mosquito larva
从环境水样和土壤中分离出18种细菌，测试其对8日龄蚊幼虫的杀灭活性，发现芽孢杆菌属、梭菌属和孢子乳酸杆菌属等具有较高活性，可作为生物杀虫剂的候选。
Malaria fever is a major disease that has killed millions of people in tropical and subtropical regions of the world. Mosquitoes are vectors of this debilitating and fatal disease. Therefore, mosquito control becomes paramount using environmentally friendly biological agents instead of chemicals. Water samples obtained from the gutters and water logged areas and soil samples analyzed resulted in 18 different bacteria isolates identified as Staphylococcus sp., Streptococcus sp., Shigella sp., Salmonella sp., Kiebsiella sp., Micrococcus sp., Escherichia coli, Pseudomonas sp., Proteus vulgaris, Proteus penneri, Bacillus sp., Serratia sp., Sporolactobacillus sp., Listeria sp., Clostridium sp., Lactobacillus sp., Enterococcus sp and Citrobacter sp. The activities of these bacteria against 8 day old mosquito larva at different concentrations and volumes were determined. At the end of the screening period of 7 days with bacteria concentration of 3.0 x 108 cfu/ml, Bacillus sp. showed 80% activity, Clostridium sp. 50% activity, Proteus vulgaris and Proteus penneri 20% activity each against the mosquito larva. At bacteria concentration of 3.0 x 109 cfu/10 ml, the activities of the bacteria against the mosquito larva were Bacillus sp. 100%, Clostridium sp. 85%, Sporolactobacillus sp. 60%, while Proteus vulgari and Proteus penneri 40% each. Lactobacillus sp had 35% activity. The rest of the bacteria isolates had no activity or insignificant activities. Other than Bacillus sp which is a known bioinsecticide, Clostridium sp. and Sporolactobacillus sp. can be genetically modified to be used as bioinsectides as man continues to search for alternative means of combating mosquito borne diseases. Key words: Larvicide, larva, gutters, mosquito, vectors, activity.