Rhizocotonia solani
Rhizocotonia solani
Assist prof Dr: Farkad Hawas Musa Department of biology
eps.farqad.hawas@uoanbar.edu.iq
Rhizoctonia solani (R. solani) is an important pathogenic fungi that lives in the soil in the form of sclerotia and does not generate asexual spores. It has a wide host range and distribution and causes sheath blight in some field crops, such as corn , lawn grass and cucumber .
Currently, Rhizoctonia disease is managed by cultural practices, such as crop rotation with grains, and methods that minimize prolonged contact of the plant with the pathogen, such as planting in warmer, drier conditions to promote rapid sprout emergence and promptly removing tubers from the field . Chemical fungicides are often used when losses from R. solani are substantial. However, current cultural and chemical controls are not completely effective, and Rhizoctonia disease remains a persistent problem.
Seed health testing for the presence of seed borne pathogens is an important step in the management of crop diseases. Seed –borne pathogens have been involved in seed rots during germination and seedling mortality leading to poor crop stand , reduction in plant growth and productivity of crops .
The root rot and wilt disease of mung bean had caused extensive plant loss and appeared to be a limiting factor in the commercial production of mung beans .
Rhizoctonia solani, a deturomycete fungus, was divided into 12 anastomosis groups (AG1-11 and BI) according to hyphal anastomosis behavior, cultural morphology, host range, pathogenicity and so on . Among these groups, isolates of AG-1 have been recovered from many hosts . Furthermore, AG-1 has been subdivided into three subgroups designated as AG-1IA, AG-1IB and AG-1IC . The common symptoms of Rhizoctonia disease are referred to as damping-off, sheath blight, sheath spot, leaf blight and rot . R. solani AG-1 IB is a widely existing fungus with great harm to many plants.