Abstract
Flies on livestock farms pose a significant problem by spreading diseases and causing stress to animals, which leads to reduced milk production and meat quality. Flies mainly breed in calf barns with wet bedding, as well as in manure, piles, and slurry under slatted floors. Non-chemical solutions, such as biopesticides containing entomopathogenic nematodes, are increasingly favored due to their high efficacy in controlling insects without harming the environment or animals. The aim of the study was to evaluate which of the commercially available nematode preparations, containing different nematode species, exhibits the highest survival in cattle manure and the highest efficacy against Galleria mellonella larvae under laboratory conditions. The study was conducted in three experimental variants: the Entonem preparation containing larvae of Steinernema feltiae (Sf), the Capsanem preparation containing larvae of Steinernema carpocapsae (Sc), and the Larvanem preparation containing larvae of Heterorhabditis bacteriophora (Hb). Each variant included 15 containers of cattle manure to which 2000 infective juveniles were applied on the first day of the experiment. On the day of application, and subsequently on days 2, 4, 6, and 8 after nematode application, ten G. mellonella larvae were placed in three containers from each variant. Forty-eight hours after adding the G. mellonella larvae to the containers, the dead larvae were dissected, and the presence of nematodes was determined using a stereomicroscope. The results indicated that the preparations differed significantly in their persistence in cattle manure and insecticidal efficacy. For Capsanem, the highest mortality of G. mellonella larvae (100%) was achieved 4 days after nematode application. Entonem showed variable efficacy, with the highest mortality of G. mellonella larvae (76.7%) recorded on day 6 after nematode application. In contrast, Larvanem maintained high efficacy from day 2 to the end of the study (83.3-96.4%). These results indicate that Larvanem can be an effective tool for long-term control of insects that develop in cattle manure.