What pesticides are effective for controlling rice pests and diseases?
Rice is one of the most important food crops in Southeast Asia, and it is widely cultivated in southern China. Its cultivation history can be traced back to about 12000-16000 BC in Hunan, China. The Records of the Grand Historian records that rice was already widely planted during the reign of Yu the Great. So what pesticides are used for rice pests and diseases?
1. What pesticides are used for rice pests and diseases
Common rice pests and diseases include rice blast, rice sheath blight, bacterial leaf blight, striped stem borer, yellow stem borer, rice planthopper, and others. Different diseases require different pesticide treatments. When rice becomes diseased, the type of pest or disease should be determined according to the specific symptoms, and targeted measures should be taken to suit the case.
Rice blast is one of the important diseases of rice and can cause large-scale yield reduction. In severe cases, yield can be reduced by 40%-50%, or even result in total crop failure. The specific symptoms are that the base of the diseased seedling is grayish black, the upper part turns brown, and finally the rice curls and dies. When humidity is high, a large amount of grayish black mold layer is produced on the diseased part. The main pesticide treatment method is to spray 20 g-25 g of tricyclazole or 28 g-40 g of isoprothiolane per mu for control.
Rice sheath blight is one of the most common major diseases of rice. Generally, early rice is more severely affected than late rice. In severe cases, it can cause the plants to lodge and die, and it is also called banded leaf blight. The main symptoms are that small dark green water-soaked spots first appear on the leaf sheath near the water surface, and later gradually expand into long oval band-like lesions. The edges of the lesions are brown, the centers are light brown to grayish white, and when moist the lesions are grayish green, water-soaked, and semi-transparent. The main control method is to spray 10 g-12.5 g of validamycin per mu plus 50 kg of water 1-2 times.
Bacterial leaf blight mainly occurs on leaves and leaf sheaths. At first, small semi-transparent yellow spots appear on the leaf margin, and later develop along one or both sides of the leaf margin or along the midrib into wavy yellow-green or gray-green lesions, with a clear boundary between the diseased part and the healthy part. The main chemical control method is that in areas where bacterial leaf blight frequently occurs, spray 30 g-40 g of bismerthiazol per mu plus 50 kg of water at the early stage of the disease. Especially after disasters such as strong winds, heavy rain, and floods, when rice leaves are damaged, the above pesticides should be sprayed in time to prevent an outbreak of the disease.
The striped stem borer and yellow stem borer are both among the most serious common pests on rice in China. They bore into and feed on the rice stems and can occur at all stages of rice growth. They easily cause dead heart sheaths and dead heart seedlings, dead booting panicles and white heads, and half-dead panicles and insect-damaged plants. The main pesticide treatment method is that at the peak of dead heart sheaths in rice seedlings, spray 36 g-45 g of bisultap or 45 g-55 g of monosultap or 20 g of triazophos per mu mixed with 50 kg of water.
The rice planthopper is one of the most common insect pests of rice. Adults and nymphs pierce and suck plant sap to damage rice and other crops, and their excrement often causes mold to grow, affecting rice photosynthesis and respiration. In the field, affected rice clumps often start from spots and patches, and from a distance look shorter and yellower than normal rice plants. The main pesticide treatment method is that when the number of insects reaches 1500-2000 per 100 clumps, use 7 g-10 g of buprofezin or 1.5 g-2 g of imidacloprid per 667 sq m mixed with 50 kg of water, and spray toward the middle and lower parts of the rice plants.
The above are the main pests and diseases of rice. When growing rice, patrol the fields more often, observe abnormal phenomena in rice, and after discovering pests or diseases, promptly take targeted measures for treatment.