Rhizoctonia Disease and Its Management

Abstract

Sugar beet (Beta vulgaris L.) has been grown for centuries as one of the most important agricultural plants worldwide for the purpose of white crystal sugar production. A large number of pathogens are present on the sugar beet, causing a large number of various symptoms and damaging production in a big scale. Plant diseases and pests are present on leaves and roots, causing damage to the above- and below-ground parts. Rhizoctonia solani Kuhn. is one such disease that attacks the sugar beet and is widespread throughout the world. R. solani is a soil-borne pathogen that survives in soil, where its life cycle is maintained for a long time period. It grows in the temperate and continental climate zone, making it a very important pathogen with respect to this crop due to its favourable condition. It overwinters in the soil for many years in the form of sclerotia or mycelium. The first symptoms appear on the upper part of sugar beet plants; usually symptomatic plants appear in bordered zones, often present in certain parts of the field with a clearly bordered belt. The infected plants have lost their turgor, and most of the leaf rosette gets laid on the ground. In the cross section, the central part of the root is initially healthy, while the disease is primarily observed on the rim of the root. The most important and only fully effective approach in controlling R. solani is the application of fungicides from SDHI and QoI groups at the appropriate time of application.