In the Lviv region the dangerous sunflower disease sclerotinia is recorded everywhere

Prolonged rains and excessive soil and air moisture in the Lviv region led to the manifestation of sclerotinia (white mould) on sunflower. Another cause was the over-saturation of crop rotations with sunflower and soybean. Yurii Yakubchuk, manager of the Lviv region for the DEFENDA brand, told SuperAgronom.com about the problem of plant infection with white mould.

The disease affects the stems, heads and root collar. It causes the greatest damage to sunflower, soybean and rapeseed.

"There are several forms of sclerotinia: the root form, the stem and the head form.

• The root form, when the plant wilts, a watery rot appears on the root collar, which turns white, and then a white coating of mycelium of the fungus Sclerotinia sclerotiorum forms. As a result the plant dries out or falls over completely," the specialist said.
• The stem form appears in the form of light-brown spots on the stem, in the middle or in part of the stem. It becomes soft, watery and dries out. Cavities with black sclerotia form on the stem.
• With excessive moisture in the soil and high air humidity, the head form of sclerotinia appears, which is the most dangerous. On the back side of the head, watery spots appear, which grow and infect the seed. It becomes shrivelled and underdeveloped.

"During heavy rains sclerotinia can completely destroy the plant. The stems break, the heads fall off, so protection measures should be taken in advance. Ideally, take sunflower out of the crop rotation for a period of five years, since this is the minimum period during which the sclerotia are preserved in the soil. Thanks to them the disease pathogen overwinters," the specialist adds. The main measures of protection against sclerotinia are growing resistant hybrids, deep tillage and chemical protection that includes preventive treatments.

Source: superagronom.com