The Tungro rice disease is a major danger to global rice production. It is caused by two viruses spread by leafhoppers, the Rice tungro bacilliform virus (RTBV) and the Rice tungro spherical virus (RTSV). The principal vector for disease transmission is the green leafhopper. Tungro disease affects rice crops at all stages of growth, but it happens most often when the plants are still green. When the two viruses work together, they change the color of the leaves, slow growth, reduce the number of tillers, and make the grain less.
The disease has the potential to affect crop production and grain quality drastically. Tungro infects not just cultivated Rice but also some wild rice and other grassy weeds in rice paddies, making it a perennial nuisance for rice growers. Plants infected have yellow or dead spots on their leaves, which can cause them to die and wilt completely. The disease can reduce grain output by remaining partly or empty.
Rice Tungro disease management in Paddy
The causal organism of Rice Tungro disease
- Rice tungro disease is caused by two viruses, Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). It is transmitted by leafhoppers, particularly the green leafhopper.
- Leafhoppers can acquire the viruses from infected plants by feeding on them quickly and immediately transmitting them to other plants within 5-7 days.
- The rapid spread of the disease through the rice crop can result in widespread infection and significant crop losses.
- To manage Tungro disease, farmers must control the population of leafhoppers and prevent the spread of the viruses through insecticides or by promoting the growth of natural predators.
Favorable conditions for the spread of Rice Tungro disease
- The presence of viral hosts.
- The vector is present.
- Host plant age and susceptibility.
- Synchronization of the mentioned three elements.
- All stages of rice plant growth, particularly the vegetative stage
- Tungro infection can develop at any stage of the rice plant’s growth. It is particularly common during the vegetative period. Plants are particularly susceptible when they are tillering.
Symptoms of Rice Tungro disease in Paddy
- Tungro causes stunting and reduced tillering in plants.
- The leaves become yellow or orange-yellow and may have rust-colored markings.
- Yellowing begins at the tip of the leaf and may progress to the bottom portion of the leaf blade. The third leaf from the top of the most affected plants is taller than the others.
- Young leaves are frequently sprinkled with pale green to yellowish interveinal stripes. In contrast, older leaves may have rusty streaks of varying diameters.
- Flowering is delayed, and the panicles are tiny and need to be fully developed.
- The majority of panicles have infertile or partly loaded grains.
- If the plants become infected too soon, they may die.
- Tungro virus illness impacts all phases of rice plant growth, with a focus on the vegetative stage.
Percentage of yield loss due to Rice Tungro disease in Paddy crop
- Rice in South and Southeast Asia is susceptible to a disease known as tungro, which is the most damaging disease of Rice. In extreme circumstances, sensitive Tungro cultivars that were infected at an early development stage might suffer a yield loss of up to 100 percent.
- As soon as tungro is present in the field, its incidence in young rice plants begins to overgrow. The young rice plants are the plants that leafhopper vectors like to feed on the most. They can also acquire tungro viruses from younger plants that are already infected with them.