Rice ragged stunt

Rice ragged stunt is a severe viral disease affecting rice production, caused by the Rice ragged stunt virus (RRSV), a member of the genus Oryzavirus. This disease is known for causing significant physiological disruptions in the rice plant, leading to stunted growth and substantially reduced grain yields.

The transmission of RRSV is exclusively mediated by the brown planthopper (Nilaparvata lugens). The insect acquires the virus from infected plants and remains a vector throughout its adult life, facilitating the spread of the disease within and between neighboring rice fields during the cropping season.

Symptoms of the infection typically include severe stunting of the plants and the characteristic ragged, serrated edges of the leaf blades. In many cases, vein swellings or galls form on the leaves and stems. Affected plants often display delayed heading and may produce sterile or malformed panicles, preventing proper grain filling.

Environmental conditions that favor the proliferation of the brown planthopper, such as high relative humidity and warm temperatures, directly contribute to the outbreaks of the disease. Furthermore, intensive rice cultivation practices that create a year-round host availability are key drivers for the widespread transmission of this viral agent.

Effective management requires an integrated pest management (IPM) approach. Primary strategies include the use of resistant rice varieties and the implementation of cultural practices like synchronous planting to disrupt the insect vector's life cycle. Chemical control of planthopper populations is essential during early growth stages to minimize initial disease incidence.