The role of water stress in Macrophomina phaseolina (Tassi) Goid. formation in soybean tissues

It is shown, that in favorable conditions for development of the disease excitant the fungus M. phaseolina gets into a plant at the earliest stages of its development, without cells destruction. Caused by water deficiency increase of concentration of soybean cellular juice at any stage of ontogenesis defines development of a physiological drought for pathogen mycelium. Osmotrophic malnutrition of pathogen at any ontogenesis stage of soybean causes fungus microsclerotium formation in mycelium localization. The most harmful is microsclerotium formation in metaxylem vessels, causing emboly and damage of soybean plants.