The occurrence and control of rice smut
Rice smut disease occurs in all rice areas. The diseased rice ear, the empty rate increased, the 1000-grain weight decreased, the broken rice increased, affecting the yield (general production 5% -10%) and quality, a large number of people have a certain impact on human health. Symptoms of rice were mainly susceptible to disease at the heading and flowering stage, and the pathogens affected the upper grain of the ear. Onset granules revealed a yellowish-green, small sclerotia at the joints of the glume. The sclerotia encased the whole glume after swelling. The sclerotium was dark green and had a smooth surface. Finally, it was cracked and black-green powder was scattered. Incidence conditions (1) in the rice break, heading, flowering period of rain and sunshine, high relative humidity is very conducive to the incidence of rice smut disease. The bacteria developed well at a temperature of 24-32°C, and the optimum temperature was 28°C. Below 12°C, no growth occurs above 36°C. (2) The incidence of different rice varieties varies greatly. Generally, spike-type or late-maturing varieties are more susceptible to disease incidence, while those with early spike-type spikes have a lower incidence. (3) The incidence of different fertilization methods is different. Under the same amount of fertilization, the condition is aggravated with the increase of the amount of panicle fertilizer. In addition, partial application of nitrogen fertilizer, deep-water irrigation, field water layer dry too late after the onset of weight. Control measures (1) Choose disease-resistant varieties and establish disease-free seed fields. (2) Improve the cultivation measures, make reasonable fertilization, increase phosphorus and potassium fertilizers, prevent late application of nitrogen fertilizer, excessive, excessive panicle fertilizer, water layer too deep. Promote sparse planting, seedling growth, and improve ventilation and light transmission conditions. Do a good job in autumn, and bury the pathogen in the soil. (3) Seed disinfection with 50% carbendazim 1000 times soaking for 48-72 hours. In the 7-10 days before rice heading, with 6% meloxone powder 1.5-2 kg per mu or 150 g DT fungicide, 50 kg water spray, the control effect is very good.