Classification standard and control method of rice blast

Grading standard leaf blast: grade 1 sporadic occurrence, careful investigation showed that the disease was slightly more in grade 2, the disease was common in grade 3 in the lower part, the disease was more severe in grade 4 in the middle and lower part, and the disease was concentrated in the middle and upper part of the disease. There are a small amount of falling pond rice blast in grade 5 and serious disease, there are obvious falling pond panicle blast: grade 1 sporadic occurrence of white ear The whole field loss rate is less than 5% (excluding 5%), the whole field loss rate is 5%, 10%, 10%, 10%, 10%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25%, 25 (1) selecting suitable local disease-resistant varieties according to local conditions. (2) leave seeds in disease-free fields, treat diseased rice straw and eliminate pathogens. (3) according to the law of fertilizer requirement of rice, the technology of formula fertilization was adopted to achieve the alternation of dry and wet in the later stage, so as to promote the ripening of rice leaves and enhance the disease resistance. (4) seed treatment: soak the seeds in 56 ℃ warm soup for 5 minutes. Soak the seeds with 1000 times of 10% 401 antibacterial agent or 2000 times of 80% 402 antibacterial agents and 1000 times of methyl thiophanate (methyl thiophanate) wettable powder for 2 days. Soak the seeds in 2% formalin for 20 minutes, then cover the seeds with film for 3 hours. (5) Pesticide control. Seize the critical period and use medicine at the right time. Catch the leaf blast and treat the ear blast ruthlessly. At the initial stage of the disease, 20% tricyclazole (chlorpromazole) wettable powder was sprayed with 1000 times or 1000 times with 40% rice disinfectant (Fuji 1) EC, 50% carbendazim or 50% thiophanate methyl wettable powder.