[A trial of the possible joint use of mermithids and bacterial preparations for the control of mosquito larvae].

The action of bacterial insecticides based on Bacillus thuringiensis H-14 and B. sphaericus in a dose of 0.005-2 mg/l on the mermithids Romanomermis iyengari, R. culicivorax and R. jingdeensis was studied. It was shown that though bacterial agents suppressed mermithid preparasite larvae density about 30-40%, the survivors might invade 100% of mosquito larvae. The viability and fertility of adult mermithids did not change under the influence of bactoculicide in doses 5-50 times higher than those used against mosquitoes in practice. In combined field trials of sphaerolarvicide (1.5 kg/ha) and R. iyengari mermithids the infectivity of Anopheles sacharovi larvae reached 96%. Mermithids in combination with bactoculicide and sphaerolarvicide might be useful in integrated control systems because these bacterial agents are harmless for mermithids of all stages in doses useful against mosquito larvae.