Dominant fungal diseases of garden strawberries (Fragaria ananassa Duch.) within the territory of Ukraine

Abstract

Today, the area under strawberries is growing every year. Because it is valued for its unpretentiousness to soil conditions, early and rapid fruit ripening, stable yields and resistance to low temperatures. But researchers note a reduction in yields in areas occupied by industrial strawberry plantations in horticultural farms due to the negative impact of the spread of fungal diseases. Gray mold (Botrytis cinerea Pers), verticillium wilt (Verticillium albo-atrum Reinke et Berth.), white spot (Ramularia tulasnei Sacc) and brown spot (Marssonina potentillae P. magn. f. Fragaria Man.), late wilting (Phytophthora fragariae Hick), late blight (Phytophthora cactorum (Leb. et Cohn.) are the dominant fungal diseases of garden strawberries in Ukraine. White spot affects the leaves, petioles, peduncles, sepals and stalks of garden strawberries. When affected by the disease, the appearance of reddish-brown spots is observed, which eventually acquire a white color and a dark red rim appears around. Brown spot mainly damages the leaves of strawberries, which affects the photosynthesis of the plant. Signs of this disease are the appearance of light olive spots, which later turn yellow, and on the underside of the leaf a plaque from light gray to green-brown color is formed. Gray mold fungus affects the leaves, flowers and fruits of garden strawberries. A "fluff" of conidia is formed on berries. They soften, change color to brown and rot. Infection of strawberries with verticillium wilt occurs through the root system. After penetration of the pathogen into the plant, the formation of chlorotic spots is observed. Eventually, the leaves turn yellow, dry up, the conductive tissues are destroyed and the plant dies. Two forms of phytophthora wilting of garden strawberries are described. In the first form, the color of the leaves changes from red to yellow-brown, which then withers and dries. The plant itself lags behind in growth. The second form of the disease affects the root system. The roots turn gray or brown and die. Signs of late blight rot are visible on the roots of strawberries in late autumn, and on the aboveground organs in the spring. Brown ring spots are formed on the root neck, which turn into rot. Necrosis appears on the stem and veins of the leaves, after which the young leaves slow down their growth and dry up. When the plant is affected by pathogens, there is a decrease in yield: white spot causes 10–30 %, brown spot – up to 50 %, gray mold – 30 %, wilting (late blight, verticillium wilt) and late blight – up to 50–60 %. Therefore, since fungal diseases cause a decrease in yield and quality of the species composition of strawberries, it is necessary to develop a system of protection, using agronomic, biological and chemical methods of control.