Rice Diseases Factsheets

1
Bacterial blight (Xanthomonas oryzae pv. oryzae)

Disease development is favored by temperatures between 26-34°C. (optimum temperature for initial infection is 20°C) and a relative humidity (RH) above 70%.

2
Bakanae Disease of Rice (Fusarium fujikori)

The disease occurs at any stage of rice growth but its most damaging at seedling stage.

3
Brown Spot (Cochliobolus Miyabeanus)

-The disease is more common in fields have water and nutrient deficiencies.
-Besides rice, the fungus attacks several grasses, including rice, wild rice, cutgrass and maize.

4
False smut (Ustilaginoidea virens )

The disease is severe under high humidity (>90%) and temperatures between 25-30oC

5
Leaf Scald (Microdochium oryzae)

Disease severity increases if excessive nitrogenous fertilisers are applied in the field

6
Rice blast (Magnaporthe oryzae)

The disease occurs under long periods of free moisture which leads to continuous leaf wetness (>10 hours) and a high relative humidity (RH>90%). The optimum temperature range for infection is 25-28°C.

7
Rice blast Management Strategies

Improve content of silicon in the soil by application of silicon at a rate of 1000 Si Kg/ha. Silicon strengthens the plant cell wall which is a natural barrier that protects plants from attack by disease causing agents

8
Rice Sheath Rot

Rice sheath rot is a disease complex caused by various fungi and bacterial pathogens with Sarocladium oryzae, Fusarium spp. belonging to the Fusarium fujikuroi complex and Pseudomonas fuscovaginae being the main pathogens involved.

9
Rice Yellow Mottle Virus (RYMV)

Crop loss ranging 10-100% have been reported depending on plant age and level of disease resistance in the  host plant. The highest yield losses occur when plants are infected early in the growing season

10
Sheath blight (Rhizoctonia solani)

The fungus infects using sclerotia (survival structures) and mycelia. It does not form asexual spores.