Biocontrol Potential of Metarhizium Anisopliae (Hypocreales: Clavicipitaceae), Isolated from Suppressive Soils of the Boyer-Ahmad Region, Iran, Against J2s of Heterodera Avenae

In order to study the nematode parasitic fungi, eighty soil samples were collected from different regions of Boyer-Ahmad, Iran. Extracted nematodes were examined for fungal parasitism. The naturally parasitized nematodes were surface sterilized and cultured on lactic acid containing media, then incubated at 25°C for 7-10 days. Metarhizium anisopliae was isolated from five soil samples. An in vitro test of the potential antagonistic efficiency of M. anisopliae against J2s of Heterodera avenae was evaluated. Nematodes were exposed to concentrations of 103, 104, 105, 106, and 107 conidia per ml. Results showed that the isolated M. anisopliae is highly pathogenic to them. The number of parasitized J2s varied between 14.9% and 47.1% for 103 and 107 conidia per mL, respectively. To assess the optimum temperature of the isolate, cultured fungi were incubated at 20, 25, 27, 30, 35, 37, and 38°C. The optimum temperature for growth was 27-35°C and no growth was observed at 38°C. This is the first report of a natural occurrence as well as the biocontrol potential of M. anisopliae on nematodes in Iran.