The virus that causes rice tungro disease is a mixture of two viruses that are spread by leafhoppers and these are given below.
- Rice tungro bacilliform virus( RTBV)
- Rice tungro spherical virus( RTSV)
( RTBV) develop the symptoms but the ( RTSV) transmits the disease.
Transmit vector: male, female, and nymphs of leafhopper( Nephotettix virescens)
- if this disease occurred in the rice plant, the rice plant will be a very stunt, give low tiller and delay in the maturity.
- The leaves of the rice will be yellow or orange in color.
- Discolored brown spots are distributed from the tip of the rice plant to the downward.
- Sometimes new leaves look like wet and old leaf have crimson color dots.
- Tiller won’t grow and the roots of the plant will be weak.
- If this disease occurred heavily, then panicle won't have uniformity and fruit, small fruit, and have sterile fruit.
Why and how it occurs?
- This disease is transmitted by the green leaf grasshopper.
- These grasshoppers soak the green liquid from the rice plant, if they are soaking from the infected plant then that grasshopper act as a disease transmitter into a healthy rice plant. This disease can transmit very fast in 5-7 days.
- This disease occurs in all stages of the rice plant which is from nursery to mature stage.
- If we grow the plant in an infected rice nursery
- By different alternative hosts like grasses, weeds, Cyperus, Cynodon, etc.
- This disease highly occurs in the irrigated lowland.
- Cultural Practices:
- Rice should be transplanted in low density, should not transplant more than 2-3 plants per hill.
- Plowing should be done effectively and make weed-free and destroy the alternative host of insects.
- Chemical fertilizer should be used in balance rate and nitrogen content fertilizer apply in 3-4 split doses.
- Use the disease-free or resistant variety of rice
- Choose the disease-free healthy seed for the seedbed.
- Follow the crop rotation system and conserve beneficial pests.
- The microorganisms of this disease stay in the old or new stubs or bases and alternative hosts like weeds for their further growth and reproduction at the time of lack of the main host. So we have to destroy all the unneeded shelter of this disease casual organism.
- Don’t grow the spring and summer rice in the same field in the same year. ( Avoid double cropping system)
- Irrigation should be in a required amount not more and less than the needed amount cause if irrigation is done more than the needed amount this disease infestation in higher rate too.
- In the interval of 3-4 days, the level of water in the rice field should increase, decrease and dry.
Source: MDPI and IRRI
- Chemical control:
- Spray the neem content insecticide aziriractidin 0.03 % EC at the rate of 3-5 mm per 1 liter of water
- If only the infestation of insects of high then we have to choose a chemical control method
- Spray Acephate 75% SP at the rate of 1 gm per liter of water
- Spray Thiamethoxam 25% WG at the rate of 1 gm per 3 litres of water
- Spray Imidacloprid 17.8% SL at the rate of 1 mm per 3 litres of water
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