Sugarbeet root rot in drought conditions

Abstract

In recent years several types of sugarbeet root rot have occurred in our country causing significant economic damage. The most frequent symptoms are leaf chlorosis and brown-black wet necrosis of the root. The necrosis spread through the entire root and vascular strands. In the course of this study F. oxysporum was the most frequently isolated from infected sugar beet roots. The incidence of other fungi (Fusarium solani, Rhizoctonia solani and Macrophomina phaseolina) was much lower and it depended on weather conditions. High temperatures occurring during dry years encourage the development of F. oxysporum, the causer of sugar beet root rot. In 2000, an extremely dry year, plant vitality was satisfactory in the experiment with irrigation and the average root rot incidence was low (2,91%). In the nonirrigated variant the average incidence was high (71,02%). It may be concluded on the basis of the results from five years (2000-2004) that the major causal agents of sugarbeet root rot in our country are species from genus Fusarium, especially F. oxysporum. Fusarium wilt and root rot are due to the increased frequency of dry and warm years.