Dr. Murai Éva szerk.: Parasitologia Hungarica 22. (Budapest, 1989)
Larvicidal effectiveness of diflubenzuron on fly breeding sites in cattle houses Dr. András DEMÉNY Department of Parasitology and Zoology, University of Veterinary Science, Budapest, Hungary "Larvicidal effectiveness of diflubenzuron on fly breeding sites in cattle houses" - Demény, A. - Parasit. hung., 22_: 87-92, 1989. ABSTRACT. A field study was conducted to evaluate the larvicidal effect of diflubenzuron spraying of fly breeding sites on a cattle farm In Hungary. 0.1% and 1.0% aqueous solutions of Dimilin^ WP-25 were sprayed once at a rate of 0.7 g/m^ and 0.5 g/m^ effective substance in a calf house and in a cow barn, respectively. Fly rearings from the samples taken before and after spraying indicated that the fly community had considerably changed due to the treatnent. Although the numbers of Musca domestica and Coproica hirtula imagoes emerging from the calf house samples were higher after the treatment than before it, signs of damaged chitin synthesis were found in 80% of Muscid pupae and in 9% of C. hirtula imagoes. The extreme decrease of total Diptera, the numerous abnormal, dead Muscid praepupae, and the total lack of parasitoids in the cow barn samples taken after treatment give evidence of a high larvicidal effect. Pteromalid parasitoids with irregular cuticle were also found . R KEYWORDS: Dimilin WP-25 (diflubenzuron), Diptera, filth flies, cattle houses, breeding sites, Pteromalidae. •p Diflubenzuron (Dimilin , TH 6040) is an insect growth regulator that interferes with chitin synthesis in immature insects (POST and VINCENT 197.3; POST et al. 1974). Several laboratory studies were conducted on its efficacy against different fly species (e.g. WRIGHT and HARRIS 1976; WRIGHT and SPATES 1976; WRIGHT et al. 1978; KNAPP and HERALD 1982; FARKAS and SOUNTHONE 1985). Spraying of grazing cattle with diflubenzuron resulted in inhibition of horn fly (Haematobia irritans ) development in a field population (KUNZ et al. 1977). Diflubenzuron was used as a feed additive for the control of Musca domestica inchicken manure (MILLER et al. 1975) and pig faeces (RIBBECK et al. 1987), as well as for the control of H. irritans in cattle manure (BARKER and JONES 1976). Chicken manure was sprayed with Dimilin in poultry houses, then randomly taken manure samples were tested under laboratory conditions by using first-stage housefly larvae (ABLES et al. 1975). Diflubenzuron was sprinkled through the slatted floor of a pig weaning house after cleaning and before restocking for the control of a multiresistant strain of Musca domestica (WEBB and WILDEY 1986). A detrimental effect of Dimilin against nontarget insects in cattle dung was detected (PICKENS and MILLER 1975); however, it did not interfere with the emergence of some parasitoids of housefly in chicken manure (ABLES et al. 1975).
