Bacterial grain rot of rice

Bacterial grain rot of rice is caused by the gram-negative bacterium Burkholderia glumae. It is a highly destructive pathogen known to cause significant economic losses in rice-growing regions worldwide, leading to poor grain filling and panicle blight.

The primary host for this pathogen is rice (Oryza sativa). The bacteria typically infect the rice plant during the flowering stage, exploiting high-moisture conditions to colonize the florets, husks, and developing grains, often leading to total yield failure.

Typical symptoms include the discoloration of panicles, which turn dark brown or black. Affected grains appear shriveled, empty, and discolored. In many cases, the panicle remains upright because the grain is not sufficiently filled, and the internal tissues exhibit necrosis, often emitting a distinct foul odor.

The disease thrives in hot and humid climates. Optimal temperatures for the bacteria range between 30°C and 35°C. Heavy rainfall during the flowering period significantly increases the spread of the pathogen, as bacteria are easily disseminated through water splashes and contaminated irrigation water.

Effective management requires an integrated strategy to minimize the impact of the disease. Farmers should prioritize the use of certified pathogen-free seeds and investigate resistant cultivars. Field hygiene is critical; removing crop debris and managing nitrogen fertilization to prevent excessive canopy density can reduce the severity of outbreaks. Chemical control through seed treatments and timely spraying during heading is recommended in endemic areas.