Dr. Murai Éva szerk.: Parasitologia Hungarica 23. (Budapest, 1990)

Parasit, hung. 23. 1990 Laboratory studies on Hydrotaea aenescens as predator of house fly larvae (Diptera: Muscidae) Dr. Róbert FARKAS and Dr. Tibor JANTNYIK* Department of Parasitology and Zoology, University of Veterinary Science, Budapest, Hungary "Laboratory studies on Hydrotaea aenescens as predator of house fly larvae (Diptera: Muscidae)." - Farkas, R. and Jantyik, T. - Parasit. hung, 23: 103-108. 1990. ABSTRACT. The aim of this work was to determine how the density and age of immature stages of Hydrotaea aenescens and Musca domestica influenced the prédation rate during development in pig manure. If eggs or first instar larvae of both species were put together into a larval medium no prédation of Hydrotaea aenescens was observed. However, when second and third instar Hydrotaea larvae were used, no house fly emerged from the samples. It was found that one Hydrotaea larva is capable of destroying at least 5 Musca larvae during its larval development. The results confirm earlier reports on the ability of Hydrotaea aenescens larvae to kill house fly larvae in pig manure, thus showing a biolarvicidal potential. KEY WORDS: Hydrotaea aenescens, Musca domestica, biolarvicide, pig manure. Filth-breeding tlies, mainly the house fly, are among the livestock and poultry pests most difficult to control. In order to keep the flies at an acceptably low level, means other than chemical control must be sought because of the increased resistance of flies to chemical insecticides. The so-called integrated fly management programs offer good control results. They involve a combination of mechanical, chemical and biological methods of which the biological component has been investigated very intensively worldwide. Over the past two decades numerous surveys, laboratory and field trials have been conducted with several species of predators, parasites and various pathogens of manure-breeding flies (PECK 1969; PECK and ANDERSON 1969; PFEIFFER and AXTELL 1980; AXTELL and RUTZ 1986; AXTELL 1986). Among the potential agents some Ophyra species - the genus has recently been amalgamated with Hydrotaea (PONT 1986) - also seem to be suitable candidates for biological control of the house fly (THOMSEN and HAMMER 1936; DERBENEVA-UKHOVA 1940; LEIKINA 1942; ANDERSON and POORBAUGH 1964; CONWAY 1973; SCHUMANN 1982; OLCKERS and HULLEY 1984; NOLAN and KISSAM 1987). One of these species is Hydrotaea aenescens (Wiedemann, 1830), which is also known as the black dump fly. It was accidentally introduced from the United States into Europe in the mid 1960s and spread very quickly. Nowadays it can be found in several countries of this continent # At the time of the studies a veterinary student preparing his diploma work. 103