Über kombinierte Wirkungen eines Juvenoids (Altosid) und eines Bacillus-thuringiensis-Präparats (Bactimos) auf Larven der Stechmücken Culex pipiens molestus Forsk. und Theobaldia longiareolata Macq. (Dipt., Culicidae)

Exposing second and fourth instar larvae ofCulex pipiens molestus for 24 h to Altosid increased their tolerance to Bactimos. The interaction was apparent in fourth instar larvae treatment especially at the higher concentrations. Exposure bactimos to Altosid for 72 hours decreased its efficacy against the fourth instar larvae ofCulex pipiens molestus. The LT₅₀ values were significantly lower in larvae treated with Bactimos only than that treated with Altosid and Bactimos. Altosid briquets increased significantly the tolerance ofTheobaldia longiareolata larvae toBacillus thuringiensis var.israelensis at all concentrations tested. Generally, pretreatment mosquito larvae with Altosid followed by Bactimos, increased the tolerance of larvae to the bacterium, this may be due to the toxic effect of Altosid on the bacterium or to the changes in the physiological status of the treated larvae to tolerate the effect of bacterium. On the light of these studies, Altosid exhibited detrimental effect on the efficacy ofB. thuringiensis var.israelensis againstC. pipiens molestus andT. longiareolata larvae. Therefore, interactions between Altosid and Bactimos could not fit the integrated control of mosquitoes.