The emergence and development of mycoses in short-day plants under conditions of long daylight hours

Abstract

The relevance of the study of mycoses is increasing due to their widespread distribution. Field experiments were carried out on sites in the region with short daylight hours (Dagestan) and long daylight hours (Volgograd). Fungal diseases were investigated on crops with short daylight hours: cucumber, pepper, and cotton according to the methods generally accepted in phytopathology. The species composition of aboriginal and exotic infections was revealed. Each culture under conditions of long daylight hours is characterized by damage by 4-5 species of fungi. The manifestation of exotic infections is observed at the beginning of the growing season at the seedling stage. The role of the introduction of short-day plants to the northern regions in the spread of exotic species of pathogenic fungi is shown. The species composition of fungi on crops in the study areas was found to be identical. They belong to different biological groups, but saprotrophs, biotrophs and hemibiotrophs predominate. It was found that Fusarium lolii (Wm.G. Sm.) Sacc and Rhizoctonia solani Kuehn (on cotton) and Verticillium dahliae Kleb and Rhizoctonia solani J.G. moved to new areas together with seeds. Kuhn (on pepper). These species are capable of causing epiphytotics at the beginning of the growing season with a low natural infectious background. The accumulation of native species of infection in the lands adjacent to the fields during the cultivation period leads to the appearance of epiphytoties in the second half of the growing season. First of all, the assimilation apparatus, flowers, ovaries and fruits are affected.