How to identify and prevent rice smut
Rice false smut is a disease caused by Aspergillus oryzae (Chlamydomonas spp.). The disease occurs more severely in rice growth and development, so rice farmers call it "Fengniangu" or "Fengfengguo." The occurrence of both the north and the south rice areas is a major disease that deserves attention. 1. Symptoms The disease is only expressed on the ear. During the milk ripening period, the diseased grains of the glume of the glume are seen on the ear. The disease is yellow-green at the beginning, and then it gradually expands to form a flat or oval block and protrudes from the glume. At the beginning, the surface of the block was smooth, and gradually cracked and green-brown velvet was formed. The edges of diseased grains sometimes became black and gradually hardened. The whole diseased granules formed a sclerotia structure. The number of diseased grains on diseased ears was small. 1-2 capsules, up to more than 10 capsules 2. The occurrence of regular rice smut disease with sclerotia and chlamydospores wintering.The sclerotia wintering in the rice field, when the second year of spring transplanting irrigation, floating on the surface, When the environmental conditions are suitable, the hyphae can be germinated to form sub-substances, the ascospora shells can be formed in the sub-seats, and the ascospores and ascospores can be produced. When the rice plants are heading and flowering, a large number of ascospores of the bacteria are scattered with the wind and fall on the husks. If the ascospores of the cavity and the glume of the zygosae germinate, they invade the young seeds and form the diseased granules (ie sclerotia).The rice cultivars can also be invaded during irrigation, and the hyphae after germination can penetrate the young epidermis to reach the endosperm. Afterwards, it gradually developed into a thick green sputum spore.The severity of rice smut disease has a lot to do with humidity, rainfall, and fertilizer and water management: Wherever partial nitrogen fertilizer is applied, late planting, plant population density, and ear emergence When it grows too lush and green The situation is heavier; the occurrence of continuous cloudy rain and less sunshine during the period from earing to grouting often leads to severe disease; there is also a difference in disease resistance among breeds. Generally, the variety with early grains, grains, and grain density is severe. 3. Prevention and control methods To control rice smut disease, we must adopt comprehensive prevention and control measures for disease resistance, high-yield, superior seeding, reasonable cultivation, and chemical defense.(1) Selection of disease-resistant, high-yield, and superior seed varieties. Yuzhi No., etc. (2) Establish a disease-free seed field or perform panicle selection before harvest, and select disease-free and ear-sprouts for seed retention. (3) Use 12% to 2% lime-water soaking to prevent and control rice blast. After 36 hours, wash and sow germination again.(4) The combination of prevention and control of sheath blight before transplanting will increase the number of sclerotia floating on the surface of the water, burn or bury it, which can reduce the occurrence of diseases.(5) Early insertion, proper close planting, Proper combination of nitrogen and phosphate fertilizers to avoid excessive and late application of nitrogen fertilizer (6) In time of spray control, spraying 30% compound carbendazim suspension 1000 times, or 10% LI- 311 powder 500 times, or W-851 (Bordeaux liquid formulation) 150 times, all There is a significant control effect; spray 50% DT fungicide 1 to 2 times before the rice break 3-10 days, the first time before the break 10 days or so, the second time before the break 3 to 4 days, per acre The dosage should be 125 grams, and it should not exceed 150 grams, otherwise it is easy to produce phytotoxicity.