Occurrence characteristics and control techniques of rice false smut

First, the occurrence characteristics of rice false smut occur only in the panicle, generally in the rice flowering to milk stage, the infected grain, the pathogen grows in the glume, forming a rice koji with a diameter of about 1 cm instead of rice grain. The optimum temperature for germination and development of false smut pathogen was 25 ~ 30 ℃. The pathogen could not grow above 34 ℃ or below 12 ℃. Rice false smut pathogen can infect the flowers and young glumes of rice. The main stage of pathogen infection was the middle booting stage of rice, but rarely invaded after flowering. From the end of booting stage to the heading stage of rice, if we encounter the climatic conditions of high humidity, suitable temperature and small temperature difference between day and night, it is very conducive to the occurrence and prevalence of the disease. At the same time, there were obvious differences in resistance among varieties, and the occurrence of the disease was positively correlated with unreasonable application of nitrogen fertilizer, and the disease was serious in the fields with light green and low-lying humidity in the middle and later stage of rice. 2. Control techniques 1. Agricultural control: selecting disease-resistant varieties, proper sparse planting, throwing seedlings cultivation must pay attention to sparse throwing, cultivate strong and effective ears, reasonable fertilization, control the amount of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizer, apply fertilizer early to promote early development, control the amount of panicle fertilizer, change the traditional fertilization method to balance promotion method, make rice plants yellow naturally in the later stage, and enhance the disease resistance of rice. Rational irrigation, timely and appropriate shelving and drying of fields. 2. Chemical control: the suitable period of application is 15 days after rice heading (before rice hits the bud and prevents panicle blast). Spray 60 grams of Jinggangmycin or Jinggang with 20% per mu. Pyrimidine 15 ml or 16% well. Ketone. Tricyclazole 150-200g water 50ml 60kg spray control.