Statistical Evaluation Of The Larvicidal Effect Of Diflubenzuron On Culex Pipiens Larval Stages

Diflubezuron is increasingly used in areas where mosquito larvae developed resistance to other insecticides. In our community diflubenzuron is not used to control mosquito larvae. Two formulations of 1% diflubenzuron (on corn-cob EF-1, and zeolite EF-2) were tested on Culex pipiens L (larvae) on one canal in the Belgrade suburb area. The effect was followed for seven weeks after application of the formulations. Formulation EF1 achieved a reduction in mosquito L₁L₂ larvae between 23.9% and 89.4%. The change was statistically significant the 21^st and 28^th day (p<0.001), 35^th and 42^nd day (p<0.01) and 49^th day (p<0.05). The maximal reduction obtained by formulation EF2 was 69.1%. The accomplished reduction was significant on the 28^th and 42^nd day (p<0.001), 35^th day (p<0.01) and 21^st (p<0.05). Both formulations have maintained a good residual effect on the lower developmental larval stages. Maximum reduction achieved by EF1 on L₃L₄ larvae was 97.4%. Reduction of larvae was high between the 7^th and 42^nd day (66.4 - 97%). Statistically significant values were recorded on the 21^st, 28^th and 35^th day. Formulation EF2 achieved a reduction of 99.5%. A statistically significant reduction in the value of mosquito larvae was obtained on the 14^th, 21^st, 28^th, 35^th and 42^nd day.

Between the two used formulations there was no significant difference in the number reduction of lower larval stages, but for the higher larval stages EF1 proved to be more efficient.