Rice stripe

Rice stripe is a viral disease caused by the Rice stripe virus (RSV), which belongs to the genus Tenuivirus, family Phenuiviridae. It is a major agricultural pathogen affecting rice crops worldwide. The virus particles are filamentous and contain a segmented negative-sense or ambisense RNA genome, which facilitates its persistence in the host.

The characteristic symptoms of Rice stripe disease include the appearance of chlorotic longitudinal stripes on the leaves. As the infection progresses, affected leaves may twist, droop, and eventually wither. Infected plants exhibit severe stunting, reduced tillering, and often fail to produce fully developed panicles, leading to significant yield losses and low grain quality.

The transmission of the virus is exclusively mediated by insect vectors, primarily the small brown planthopper (Laodelphax striatellus). The virus is transmitted in a persistent-propagative manner, meaning it multiplies within the insect vector. Importantly, the virus is transmitted transovarially, allowing it to persist in planthopper populations even in the absence of a host crop.

Environmental conditions such as mild winters and high humidity levels are favorable for the survival and rapid multiplication of the planthopper vector. The disease tends to spread in waves, particularly when rice fields are located in close proximity to weeds or alternative grassy hosts that serve as overwintering sites for infected planthoppers.

Management and control strategies are multifaceted and focus on minimizing the interaction between the vector and the host crop. Key practices include:

• Deploying resistant rice cultivars as the most sustainable control method.
• Monitoring planthopper population densities to time chemical applications accurately.
• Eliminating weeds in and around fields to remove virus reservoirs.
• Adjusting planting schedules to ensure plants are not in the most susceptible growth stage during peak insect flight periods.