Peculiarities of growth and development of strains of the fungus — the causative agent of flax anthracnose (Colletotrichum lini) in vitro

Relevance. Among the diseases that annually cause significant damage to flax growing, anthracnose has been especially harmful in recent years. The most serious consequences of this disease are observed in the case of damage to flax seedlings, which can die partially or completely. Methods. In vitro studies. The objects of the study were strains of the causative agent of flax anthracnose Colletotrichum lini Manns et Bolley 848, 850 — highly virulent, 855 — moderately virulent, 853 — weakly virulent, flax lines and varieties susceptible to anthracnose. Results. In the studied strains of the flax anthracnose pathogen, single conidia were visually visible on the 7th day on the Sh-2 nutrient medium, on the 8th-10th day on the MS medium, which formed a jelly-like biomass by the 14th day of cultivation on the Sh-2 medium, and by the 15th– 16th day on the MS medium. By the 40th day, mycelium acquired a dense consistency on both media, and pubescent colonies of various colors appeared. It was revealed that the growth rate of the fungus and the build-up of biomass did not depend on the virulence of the strain. On the MS nutrient medium, the weakly virulent strain 853 (25.5%) had the most intense increase in biomass from the 14th to the 40th day, and the strongly virulent strain 850 (14.6%) had the least. On the Sh-2 nutrient medium, the weakly virulent strain 853 (57.8%) had the most intense increase in biomass from the 14th to the 40th day, and the strongly virulent strain 848 (36.2%) had the least. The toxicity of the culture filtrates did not depend on the virulence of the strains used and the culture medium of the strains, whereas the growth rate and toxicity of the culture filtrates were dependent. The culture filtrate of the slow-growing highly virulent 850 strain was less toxic than others.