The effect of temperature on the growth of acaropathogenic fungi from Hirsutella genus

The aim of the study was to determine the effect of temperature on the growth of four species of acaropathogenic fungi of the genus Hirsutella (isolated from mites) grown in vitro on Sabouraud (SDA) and Czapek-Dox media. The effects of seven temperature ranges (5–35°C) were tested under laboratory conditions. Observations of colony growth were carried out every 5 days until day 25 by measuring the diameter of the colonies in mm. The growth rate of the test isolates was calculated in mm per day. The conducted studies showed that the thermal optimum of most of the tested isolates of acaropathogenic fungi of the genus Hirsutella was between 20°C and 25°C, with individual values varying depending on the type of medium on which the inoculum was developed. The fungus species with the highest temperature range of colony growth was Hirsutella thompsonii var. synnematosa. It was the only acaropathogenic fungus strain tested that developed on both types of culture medium, also at 35°C. The fastest growth rate of the tested isolates of acaropathogenic fungi was at 25°C. The cultures of the tested species of fungi reached larger sizes on the SDA medium rather than on Czapek-Dox medium.