Rice Tungro Virus Control

Symptoms

Tungro is a virus disease caused by two viruses together, rice tungro bacilliform virus and rice tungro spherical virus, and is spread by green leafhoppers. Infected plants show yellow to orange yellow discolouration that starts at the leaf tip and spreads down, stunted growth, reduced tillering, and fewer and partly filled grains. The yellow orange colour and stunting in patches that match leafhopper movement are typical signs.

Damage

Tungro can cause severe yield loss, from minor up to 100 percent when plants are infected early and the variety is susceptible. Early infection at the seedling or tillering stage is far more damaging than late infection. Because it is spread by green leafhoppers, the disease can build up quickly where the vector is abundant and infected ratoon or volunteer plants persist.

Organic & cultural control

Grow tungro resistant or tolerant varieties, which is the most effective measure. Remove and destroy infected plants, volunteer rice and ratoon crops that carry the virus. Plant in synchrony across the area and avoid staggered planting so the leafhopper cannot move between stages. Conserve natural enemies of leafhoppers and keep weed hosts down. Avoid excess nitrogen which favours the vector.

Chemical control

There is no chemical that cures the tungro virus itself. Management aims at controlling the green leafhopper vector early and at removing virus sources. Where leafhoppers are high, a recommended insecticide for green leafhopper may be used in the nursery and early crop to slow virus spread, but this is only a support to resistant varieties and clean planting. Always follow the product label dose, observe the pre-harvest interval, and consult your local KVK or agronomist before spraying.

Always follow the product label, the recommended pre-harvest interval, and your local KVK or agronomist. Pesticide approvals change, so verify before use.

Prevention

Use resistant varieties, synchronise planting across the area, remove infected plants, ratoons and volunteer rice, control the green leafhopper vector early, keep weeds down and avoid excess nitrogen. Early vector control and clean fields are the backbone of tungro prevention.