As shown earlier [1], the dissipative structure formation in the colonies of imperfect microfungi depends on the culture – produced exogenous inhibitors of growth. The paper presents a model and experimental procedure which are used to estimate one of the most important control parameters [2] defining the colony structure, namely, the diffusion coefficient of liquid metabolites. An explanation is provided for the increased nonlinear phenomena accompanying mycelium fungus colony formation at low temperatures.