Sheath Blight and Its Control

Sheath blight disease is caused by the fungus (Rhizoctonia solani).

• The symptoms can be found significantly before flowering stage and also after flowering.

• Unfilled grains or even no formation of grains, if infected severely.

Symptom

• The symptoms develop on the leaf sheaths at or just above the water line in oval shape lesions of greenish-gray color. In two or three days, greyish lesions become large quickly with reddish-brown or dark-purple margin. 

• The lesions grow into each other and cause irregular lesions. The fungus spread to leaves that are in contact with the infected leaf sheaths.  

 

Disease Cycle

• The fungus will survive in the soil as sclerotium and mycelia for several years. 

• These fungus float on water surface, move along the water flows and transmitted to other rice plants.

• It can infect as seed-borne disease when it attack into the panicle.

Chemical Control

• Spraying recommended foliar fungicides is most effective for the control of sheath blight. 

• Carbendazim 250mg or Chlorothalonil 1 kg or Edifenphos 1 Lit can be applied.

recommended fungicides are;

 

• Validamycin

• Azoxystrobin 

• Trifloxystrobin 

• Metaminostrobin 20 SC