Dr. Murai Éva - Gubányi András szerk.: Parasitologia Hungarica 29-30. (Budapest, 1997)
The efficacy of treatments was assessed by the estimation of fly infestation in rearing houses and by the examination of methoprene-related bioactivity in manure samples. All of these evaluation procedures were carried out at weekly intervals. For monitoring fly infestation resting fly counts were made as well as counting flies on resting piglets in a randomly selected battery cage. To estimate resting flies, the numbers of insects sitting on five, vertically suspended, 50 x 50 cm white sheets were determined. Parallel to checking fly infestation, 3-4 kg manure samples were collected from 10 different, randomly selected places in each room. From these samples, 100 g amounts were measured into plastic containers, sealed with nylon sheets and kept at 25 °C. The development of natural house fly populations was observed in 5 containers. The group of 5 containers was kept first at -20 °C for at least 48 hours to kill unwanted organisms. These samples were each then infested with 20 first instar larvae of Musca domestica . In the latter experimental groups the number of pupae and adults which managed to emerge was also determined. RESULTS Residual efficacy of BTI B 5 GR and BIOPREN BM 5 GR preparations against mosquito larvae In this laboratory test, the larvicidal activity of the BTI B 5 GR preparation was noticed relatively early, since most insects died within 48 hours. The granule formulation completely inhibited adult emergence for 6 weeks when tested at 10 ppm and for 4 weeks when used at a concentration of 5 ppm (Fig. 1). Methoprene, the active component of BIOPREN BM 5 GR, exerted its specific morphogenetic (juvenile hormone like) action mainly on the pupal-adult metamorphosis. Therefore, most of the affected insects died at the pupal stage, sometimes just before adult emergence. In the experimental series carried out with L4 larvae of Ae. aegypti, granules tested at 1 ppm (a. i.) provided excellent bioactivity until the 6th week (Fig. 2). The use of the same preparation at a concentration of 10 ppm (a. i.) completely inhibited adult emergence in the whole experimental period of 12 weeks. The other investigation was performed with L4 instar larvae of the same species. In the latter case, BIOPREN BM 5 GR proved to be 100% effective both at 10 and 20 ppm (a. i.) concentrations even in samples taken in the last, 16th week of the experiment (Fig. 3). In the experiment carried out with larvae of Aedes cantons under simulated natural conditions, BIOPREN BM 5 GR, when tested at 0.5 ppm (a. i.), prevented the emergence of adult mosquitoes during the whole 5-week observation period (Fig. 4). Only one specimen emerged in a replicate with Li and L2 larvae. Practi10 ppm-BT! Age of iest solution (weeks) Fig. 1. Residual activity of BTI B 5 GR formulations on early L4 instar mosquito larvae in static test (Formulation type: BTI B 5 GR = 5% BTI 10,000 ITU7MG)
