Successful control of Pest and Disease of rice: Strategies for Success
Diseases of Paddy
1. False Smut
- False smut causes chaffiness of grains which leads to a reduction in grain weight and also reduces seed germination.
- The disease can occur in areas with high relative humidity (> 90%) and temperatures ranging from 25-35 degrees Celsius.
- Rain, high humidity, and soil with high nitrogen content also favor disease development.
- Fungal spores are transferred from plant to plant through wind.
- False smut is visible only after panicle exertion. Plants can become infected during the flowering stage.
- Plants infected with false smut have individual rice grains transformed into a mass of spore balls. These spores are initially orange but later transition to a greenish-black color as they mature.
Management
- Excess application of nitrogen fertilizers should be avoided.
- Spraying of Nativo (100g/acre), Folicur (200-300ml/acre), Buonos (250ml/acre), Bavistin (2ml/liter), and Tilt (150-200ml/acre) are the good chemicals for effective control of false smut.
2. Bacterial leaf blight
- When a young rice plant is afflicted by the disease, the infected plant leaves turn yellow to straw-colored. , and later it dies.
- In mature rice plants, this issue typically arises during the stages from tillering to panicle formation. Initially, the plant has a light green to greyish-green color, and you might notice water-soaked streaks on the leaves but once it gets affected by the bacterial blight, these streaks into larger, irregular-edged yellowish patches. Later leaves start turning yellow, gradually wilt, and die.
- This disease spreads more during bad weather conditions like frequent rainfall, wind, high humidity, and warm temperatures ranging from 25 to 34 degrees Celsius. More amount of nitrogen fertilizers in the field favor the disease.
Management
- A spray of streptocyclin 6gm/acre + copper oxychloride 500gm/acre combination gives good results.
- Avoid excess use Nitrogen nitrogen-containing fertilizers.
3. Blast
- Initially, you will notice white to gray-green lesions with dark green borders.
- Mature lesions on the leaves are spindle-like in shape and whitish to gray center surrounded by a reddish to brownish.
- Looks diamond-shaped, wider in the middle, and pointed toward either end.
- Lesions grow larger and merge, later covering the entire leaf and causing it to die.
- Neck and panicle infection causes chaffy grains and panicles to dry up and break down as the seeds ripen.
- The development of the disease is under specific conditions such as cool and wet weather, water stress in the nursery, and excessive nitrogen application in the field.
Management
- Avoid excess use of nitrogen-content fertilizers.
- Spray of Galileo Sensa (400ml/acre), Nativo (100gm/acre), Seltima (400ml/acre), and Kitazin (200-250ml/acre) for effective control of disease.
- Use sivic (120gm/acre) at the time of basal dose and first dose of fertilizer application as a preventive measure.
4. Brown spot of rice
- The disease is common in soil that doesn’t drain well or lacks essential nutrients.
- Symptom observed brown spots on the leaves and grains.
- Seedling blight was also observed in seedlings grown from infected seeds.
Management
- Fungicides like Tricyclazole and mancozeb.
5. Kernel smut
- This disease was observed only in grains.
- The outer part of the grain turns black, and the inside of the grain is black powder.
Management
- Azoxystrobin and tebuconazole are commonly used.
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Pests of Paddy
1. Brown Plant Hopper
- The Brown Plant Hopper (BPH) is an insect typically located near the base of paddy plants, just above the water level.
- Young and adult nymphs suck the sap from leaf sheathes, causing yellowing of lower leaves followed by upper leaves.
- A high population of planthoppers causes leaves to turn orange-yellow and turn brown burnt like later initially.
- An infestation will occur in groups and areas the plants in those particular areas may be in patches called “hopper burn”. Severe uncontrolled infestation causes much losses.
- Brown plant hopper pest is favored by moist, humid, and warm conditions and high doses of urea.
Management
- Irrigate the rice field for 3-4 days during the early stage of infestation.
- To minimize the Brown Plant Hopper, you can divide the nitrogen application.
- Avoid close planting.
- Spraying of pexalon (94ml/acre) at the time of tillering to panicle initiation gives good results.
- Spraying of chess (120gm/acre).
2. Gall Midge
- The presence of an onion leaf or silver shoot in the place of a central leaf is the prominent character.
- The symptoms appear from the nursery stage to the flowering stage.
- Formation of a hollow or tube-shaped swelling at the base of the affected tiller.
- Infected tillers show stunted leaf growth and fail to produce panicles.
- Affected plants become stunted deformed, and wilted.
Management
- In nursery apply Carbofuran 3G / Regent 3 CG @ 1kg per Ac, 7 days and 15 days after sowing.
- In the main field apply Carbofuran 3G @ 10kg/acre when infestation starts.
- Avoid late transplantation.
- Optimum recommendation of potash fertilizer.
- Spraying of Marshal (320-400ml/acre) and Regent (400-600ml/acre).
3. Yellow Stem Borer
- A brown-colored cluster of eggs near the tip of the leaf.
- Caterpillars affect the central shoot of paddy seedlings and tillers which results in the central shoot drying up, often referred to as a “dead heart.”
- In mature plants, the entire panicle dries up and becomes a “white ear”.
Management
- Fertera 0.4% GR (4kg/acre)
- Chloropyriphos 50 EC (250ml/acre)
- Carbofuran (10kg/acre)
- Caldan 50 SP (400gm/acre)
- Before transplanting, remove any egg masses. Collect and destroy these egg masses in the main field.
4. Rice Leaf Folder
- Larva fold the leaves longitudinally and larvae remain inside.
- Larva scrapes the green parts of the leaves, which later change to white and dry.
- In cases of a serious infestation, the entire field takes on a burnt or scorched look.
- The eggs are flat, oval, and have a yellowish-white color.
- Larva: Greenish translucent.
- The adult moth is yellowish-brown and has dark wavy lines in the middle of its wings, along with a dark band on the wing’s edge.
Management
- Avoid excessive nitrogenous fertilizers.
- Keep the bunds clean.
- Spraying of Fame (Flubendiamide 39.35% SC) 20ml/acre, Caldan 50 SP (400gm/acre) Marshal (320-400ml/acre), and Vayego (Tetraniliprole 18.18 SC) 100ml/acre.
5. Rice Hispa
- Leaf minor larvae, start to eat the inner tissue of a leaf, from the tip and from the tip to the basal part of a leaf, and the leaf looks like a hollow, white gallery.
- The grown-up insects are recognized as vectors of the Rice Yellow Mottle Virus (RYMV).
- You can control this insect by using Furadan 5 G.
Management
- Use pesticides like Carbosulfan 25% EC and carbofuran.
Weak Growth and Drying of Rice Seedlings due to the following reasons
- Transplanting shock.
- More standing water for a week after transplanting.
- Very low temperature after transplanting.
- Excess use of fertilizers in nursery.
- Poor land preparation for transplanting.
Soil Salinity
- Soil salinization happens due to the accumulation of water-soluble salts in soil. major types of soil degradation occur naturally or as a result of poor management of water and soil resources.
- Salinity affects the respiration and photosynthesis of plants. It also reduces the natural processes of nitrogen fixation and the release of nitrogen in the soil.
- Reduced germination rate.
- Reduced plant height and tillering.
- Poor root growth.
- Excess Sodium (Na) is absorbed by the plants, leading to a decrease in the weight of 1,000 grains and the overall protein content in the grains.
- High salt or alkaline levels in the soil may be accompanied by Phosphorus deficiency, Zinc deficiency, Iron deficiency, or Boron toxicity.
