How to treat rice diseases?

Rice is one of the main food crops in China, which is widely cultivated in the south and along the river in the north. Diseases will occur in rice if it is not managed properly. So, how to treat rice diseases?

It depends on what disease the rice has. There are three main diseases, namely rice blast, bacterial blight and sheath blight, and other important diseases are rice false smut, evil seedling disease, downy mildew and so on. The treatment of different diseases is different, and we should treat them differently.

1. Rice blast

Rice blast (Magnaporthe grisea) is one of the most important diseases of rice, which occurs in the whole growth period of rice, mainly harming leaves, stems and ears. According to the different damage period and position, it can be divided into seedling blast, leaf blast, node blast, ear neck blast and grain blast. In popular years, production is generally reduced by 10-20%, seriously reduced by 40-50%, or even no harvest.

Prevention and treatment: 30% Kexiansan EC 500x solution, 50% carbendazim water-soluble powder 500x solution, 40g Chlorothalonil suspension 500x solution, 25% Prochloraz EC 1500 times EC can be sprayed for prevention and treatment.

2. Bacterial blight

Bacterial blight mainly occurs on leaves and leaf sheaths. Translucent yellow spots appear at the leaf edge at the beginning, and then ripple yellow-green or grayish-green spots develop along one or both sides of the leaf margin or along the midrib. After a few days, the disease spot turned gray-white and curled inward, looking at a withered color from afar.

Prevention and treatment: in the early stage of the disease, the rice seedlings were sprayed with 20% fluorosilazolium 800 × 1000 times, and the changes could be observed once every 5 times every 7 days. In the middle of the disease, 20% fluorosilazolium 1000 times + 2% aminooligosaccharides 1200 times, 5% was used once in 7 days for 2-3 times.

3. Sheath blight

Sheath blight is one of the most common diseases in rice, which can occur from seedling stage to heading stage, especially before and after heading, which mainly harms leaf sheath and leaves, and seriously invades the stem and spreads to the panicle. Often cause the grain is not full, the empty shell rate increases, serious can cause plant lodging and death.

Prevention and treatment: apply the first medicine when the disease cluster rate is 20-30%, the second time every 12-15 days, and when the disease cluster rate is 40-50% in drought.

4. Rice false smut

Rice false smut only occurs in the panicle of rice, causing damage to some grains. The hyphae formed in the injured grains gradually enlarged, the inner and outer glumes split, revealing a yellowish mass, that is, the spore seat, which was wrapped on both sides of the inner and outer glumes, showing dark green, initially wrapped in a thin film, then ruptured, scattered dark green powder, that is, thick chlamydospores of the pathogen, and some had black flat sclerotia on both sides, which were easy to fall off in the wind and rain.

Prevention and treatment: first, the best time is to extract all the last leaves of more than 3 stalks of the whole field, commonly known as "big packing" or "big belly period" (about 10 days from the time of heading), which is the peak period of the initial infection of bacteria; the second is the opening and heading stage, which is generally used 3-5 days in advance.

5. Evil seedling disease

Evil seedling disease occurs in all rice areas all over the country, the mildly diseased ones heading early and the spike shape is small and unfruitful. Grain can also be damaged at heading stage, serious browning, can not bear fruit, light red mold occurs in the gap between glumes, the disease is mild and does not show symptoms, but there are already hyphae latent inside.

Prevention and treatment: strictly disinfect seeds, soak seeds with 50% carbendazim 100g, add water 50kg, or 35% carbendazim 120g, add 50kg water, soak seeds, or soak seeds with 3% raw lime water for 48 hours.

6. Downy mildew

Downy mildew is serious in the late stage of seedling field and early stage of Honda, which is harmful to the leaves of rice. The primary yellow and white spots on the leaves, and then formed irregular stripes on the surface, mottled flowers and leaves. The heart leaves of the diseased plants were yellowish, curly, not easy to extract, the lower old leaves gradually withered, the root system was stunted, and the plants were dwarfed. The injured leaf sheath is slightly soft, the surface has irregular ripples or wrinkles and twists, and the tillers are reduced.

Prevention and treatment: at the initial stage of the disease, spraying 25% metalaxyl wettable powder 800 times, 90% Shuangbengjing wettable powder 400 times, 80% Kelu wettable powder 700 times, 64% alum wettable powder 600 times, 58% metalaxyl manganese zinc or 70% ethyl phosphorus manganese zinc wettable powder 600 times, 72.2% propoxur water 800 times.