The incidence and spreading of Macrophomina phaseolina(Tassi) Goidanovich on sunflower in the Czech Republic

Abstract

VEVERKA K., PALICOVÁ J., KŘÍŽKOVÁ I. (2008): . Plant Protect. Sci., 44: 127–137. The warm climate pathogen <i>Macrophomina phaseolina</i> (Tassi) Goid., which causes charcoal disease, has been reported in the Czech Republic since 1999. The aim of our work was to study the incidence of disease between 2000–2007 in the main sunflower growing regions and analyse the relationship between weather conditions and the occurrence of the pathogen. The first and highest incidence of disease was in the Žatec region. However, in the region south of Brno there was no disease in 2000, 2001 and 2003, and only individual low incidence in other years until 2007, when the disease was found in nine localities. The incidence of the disease is increasing year by year indicating a spread of the pathogen. The warm and dry periods throughout the end of July and August have promoted the disease. However in some years where weather conditions were favourable for the pathogen, in several cases no disease was found. It is assumed, that the pathogen was not yet present in these localities. Soil conditions are critical. Diseased plants are usually distributed in several dispersed groups in the stand, especially on higher and drier parts of the field. Disease is also often found on plants suffering from compressed roots. Diseased plants had poorly developed heads and seeds.