Laboratory shelf-life of oil-formulated conidia of the locust and grasshopper fungal pathogen Metarhizium flavoviridae Gams & Rozsypal, in mixtures with the pyrethroid insecticide lambda-cyhalothrin

The addition of 20 ppm lambda-cyhalothrin pyrethroid insecticide to Metarhizium flavoviridae (Fungi: Deuteromycetes) dry conidia in oil kept germination above 80% for 2 and 12 months at temperatures of approximately 30 and 8 degrees C respectively. At 30 degrees C, conidia in oil alone maintained viability for only a few weeks, but this was doubled at 8 degrees C. Even dry conidia retained good viability for only 5 months at the higher temperature. The extended viability of conidia given by adding the pyrethroid to the oil formulation is regarded as very valuable for areas where the fungus is to be used against locusts and grasshoppers.