Impact of temperature and relative humidity on spatio-temporal fungal growth dynamics of Basidiomycetes

Basidiomycetes can cause considerable damage to wood and other bio-based building materials. Knowing at which environmental conditions these decay fungi generally thrive, and how the environmental conditions affect fungal growth characteristics, is therefore of particular interest. In this paper, we use image analysis to assess the impact of the environmental conditions on the growth dynamics of Coniophora puteana. Fungal growth characteristics were tracked over time for sixteen different environmental conditions, obtained through a combination of four temperatures (15, 20, 25 and 30 °C) and four relative humidity (RH) conditions (65, 70, 75 and 80 % RH). Advanced time series analysis was applied to objectively compare the effect of the environmental conditions on these growth characteristics. In most cases, temperature and RH had a combined effect on fungal growth dynamics, yet an RH of 65% (independent of temperature) and a temperature of 30°C (independent of RH) resulted in a cease of growth after 10 hours. When defining optimal growth conditions for a fungus, it is therefore of primordial importance that the effect of temperature and RH is assessed simultaneously. The mycelial area and the number of tips were characterized by typical sigmoidal growth curves, whereas other characteristics such as the mean edge length remained constant over time. The method applied in this study allows for a quantitative and thus objective comparison of spatio-temporal fungal dynamics. Therefore, it can easily be employed for testing other factors influencing fungal growth, including different growth substrates