The ovicidal effect of Metarhizium brunneum on Ascaridia galli eggs on solid media and activity of its crude extract

The aim of this study was to test the ovicidal effect of Metarhizium brunneum on Ascaridia galli eggs and the protease activity of M. brunneum grown on standard media enriched with A. galli eggs. Ascaridia galli eggs were transferred to water agar plates and the fungus, M. brunneum, was added as a spore suspension. The viability of the eggs was assessed at 7, 14, 21 and 28 days post-inoculation. M. brunneum was grown on three types of growth media: SDA, SDA + chitin and SDA + A. galli eggs. Crude extract of the fungus was produced by mincing and centrifuging biomass taken from the growth plate. The supernatant was added to Azurine cross-linked-casein plates to test for protease activity. M. brunneum showed a significant impact on the viability of A. galli eggs, decreasing the percentage of viable eggs to 5.1%, indicating that it is a potential candidate for biological control of this nematode. Crude extract of M. brunneum grown on SDA + A. galli eggs showed a significantly higher protease activity than the crude extract of M. brunneum grown on SDA alone and M. brunneum grown on SDA + chitin, indicating a possible ovicidal effect of these proteases. Such an extract may have potential as a safe and reliable method for nematode control.