Dr. Murai Éva szerk.: Parasitologia Hungarica 19. (Budapest, 1986)

Musca dornestica L. (HALL and FOEHSE, 1980; WILLIAMS and BERRY, 1980; MILLER et al., 1981; MULLA and AXELROD, 1983; KÜNAST and BOTHE, 1984), Musca auturnnalis De Geer (HALL and FOEHSE, 1980; MILLER et al., 1981), Stomoxys calcitrans L. (KÜNAST and BOTHE, 1984) and Fannia femoralis Stein (MULLA and AXELROD, 1983). Musca osiris is a dipterous pest of cattle and sheep in Hungary (PAPP, 1976, 1985). The laboratory stocks of this secretophagous fly species have been established (POLGÁR and PAPP, 1985) which offers anew possibility tötest the insecticides (FARKAS and SOUNTHONE, 1985). In the laboratory experiment we studied the effect of various concentrations of cyromazine on third-instar larvae of this species. MATERIALS AND METHODS 0.1, 0.5, 1 and 2 ppm concentrations of cyromazine were used. The formulation (Neporex WSG 2) was diluted in water to make the necessary solutions. When mixing the aqueous solution of the test chemical to freshly-collected bovine faeces, the active substance concentration was adjusted to 100 g. In control groups only water was used. Treated and untreated larval media were seeded with 25 early (aged 67-68 hrs) third-instar larvae of Musca osiris

. They were collected from our laboratory breeding. There were four replicates at each concentration. Table 1 The effect of cyromazine on third-instar larvae of Musca osiris Conen of AI ppm Pupae gained Pupal mortality Imagos died in different stages No. Normal imagos Conen of AI ppm Pupae gained No. Imagos died in different stages No. Normal imagos 2. 0 91 91 100 1. 0 90 90 100 0. 5 89 76 64 2 11 0. 1 97 56 48 16 25 1) 100 larvae/concn of AI 2) Corrected for control mortality by Abbott's formula The faecal samples with larvae were placed in plastic jars with sawdust. The jars were closed with gauze. The experiment was conducted in a room of 28+2°C temperature and 60+10 per cent relative humidity. The samples were checked every day. The number of the emerged imagos was recorded. After a period of two weeks abnormal pupae, incompletely eclosed adults and abnormal adults were observed, counted and examined under stereomicroscope. Evaluation was performed by using ABBOTT's formula and calculating the mortality percentage of pupae, corrected for the control mortality percentage. RESULTS AND DISCUSSION The obtained results are shown in Table 1. The majority of larvae developed further and were able to pupate at each concentration but a significant part of the resulting pupae were aber-