Rula Abu-Jreis, Naim Iraki, Asael Rot, Michael Samish

The tolerance of fungi to high temperature is an important criterion for choosing strains for controlling ticks while feeding on the warm skin of vertebrates. The efficacy of Metarhizium anisopliae var. anisopliae strains with different thermal characteristics was compared in two model experiments: 1) at temperature reflecting the common conduction on animals surface (35°C) and 2) at a relatively short increase of temperature up to the maximum that was detected on cattle skin for limited time (37°C and 40°C). The present study show that isolates suitable for application to cattle must be able not only to germinate and grow at higher temperature but also to fast recover the conidia germination and keep their virulence after temporal rise of temperature above the one in which the fungus develop and infect.