The spread of fungal leaf diseases in sugar beet crops

Abstract

In 2002–2011 the spread dynamics of sugar beet fungal leaf spot diseases were investigated. Was found that the most widespread was Cercospora (Cercospora beticola Sacc.) and Ramularia (Ramularia beticola Fautrey & F. Lamb.) leaf spot diseases. Cercospora leaf spot spread was 46.7 to 100.0 %, the severity – from 1.12 to 56.00 %, Ramularia leaf spot – from 40.0 to 96.7 % and from 1.73 to 20.00 %. Phoma leaf spot (Pleospora betae Björl.) damage on sugar beet crop was less – before harvesting disease spread was 0 % to 84.3 %, and the severity was – 0 to 15.57%. Powdery mildew (Erysiphe betae Vaňha Weltzien) in sugar beet spreaded later than other fungal diseases, but in favourable time for spread of the disease up to 100 % of the plants were infected. Disease severity was also very high – up to 65.10 %. Beet rust has been found in small quantities and only in two years of investigation. Diseases spread and development depended from the weather conditions in July and August.