Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)

cally the same prolonged efficacy was observed in the case of Altos id pellets. In the latter case two mosquitoes developed in a batch of L3 and L4 stage larvae. In closed containers, no significant difference was demonstrated between the effects of the two (2 and 10 ppm) concentrations of methoprene (Fig. 5). The BIOPREN BM 5 GR formulation gave practically 100% control for 2 weeks under these circumstances. However, over the subsequent 3 weeks its efficacy gradually decreased. Weeks liter witer treatment Fig. 2. Residual efficacy of BIOPREN BM 5 GR against L4 instar larvae of Aedes aegypti at 1 and 10 ppm a.i. (Formulation type: BTI B 5 GR = 5%methoprene) Residual efficacy of the BIOPREN 5 GR preparation against house fly larvae In these studies it was observed that methoprene, did have an immediate larvicidal effect. Most larvae developed into pupae that exhibited normal morphology. Insects were affected only afterwards, in the pupal stage, during the pupal-adult metamorphosis. The BIOPREN BM 5 GR preparation exerted a prolonged action even at the lowest concentration tested (10 mg a. i./ kg) in the "dry" teatment (Fig. 6). No marked differences were noted in the efficacy with respect to the concentrations used or the times that elapsed after treatment. Differences between means were significant in a few cases only (p=0.005, Turkey's test). In BIOPREN-treated manure samples whose surface was subsequently moistened ("wet" treatment), no house fly larvae reached the pupal stage in many experimental groups (e.g. in those samples of the two lowest concentrations which had been collected after the 2nd week). These high mortality rates among larvae could not be attributed to the action of methoprene but more probably to the high water content of the medium. Data summarised in Fig. 7 are presented only for the concentration of 50 mg a. i./kg manure, where relatively good survival until the pupal stage was observed. In this case, too, the granule formulation provided very good residual activity by killing insects at the pupal-adult transformation. In the trial conducted in pig-rearing houses (Figs 8 and 9), in the first three weeks relatively low numbers of fly adults were found, especially on white sheets. In weeks 4 and 5, after stocking the rooms with piglets, however, more flies could be seen in the control room than in the rooms where treatments had been performed. The differences are significant (p=0.05, Duncan's test). The specific effect of methonyv ut mi »uiuuun IWWWASJ Fig. 3. Residual efficacy of BIOPREN BM 5 GR against L4 instar larvae of Aedes aegypti at 10 and 20 ppm a.i. (Formulation type: BTI B 5 GR = 5%methoprene)