Symptoms are also known as rice fever, fire crickets, and steamed oysters. It is distributed in all rice areas in the country and mainly damages the leaves, stems and panicles. Because the time of damage, the site is divided into seedlings, leafhoppers, knots, panicles, and grains. Miao Miao occurred in front of the clover and was caused by the seeds. The base of the diseased seedlings is grayish black, and the upper part is browned and curled to death. When the humidity is high, the diseased part produces a large number of gray moldy layers, namely pathogenic conidiophores and conidia. Leafhopper can occur throughout the reproductive period. It is heavier to give birth until jointing. Due to the different climatic conditions and disease resistance of the varieties, the lesions are divided into four types. Chronic lesions begin to produce dark green patches on the leaves, which gradually enlarge into mottled patches, often with extended brown necrotic lines. disease
The center of the spot is greyish-white, brown on the edge, with a pale yellow halo around it, and a gray moldy layer on the back of the leaf. When the lesions are numerous, irregular large spots form continuously and the lesion develops slowly. Acute lesions form dark green near-circular or elliptical lesions on susceptible cultivars, and brown fungal layers are formed on both sides of the leaves. The conditions do not adapt to the onset of chronic lesions. After the onset of the diseased leaf, the white spot type lesion produces a white, near-circular small spot that does not produce spores. When the weather condition expands, it can turn into an acute type lesion. Brown spots are mostly on high-resistance varieties or old leaves. The brown spots that produce the size of the needle tip are only produced between the veins, and produce less sporulation. The disease can also be caused in the lingual tongue, auricle, and leaf lobe. Temperature usually occurs after heading, and brown dots are produced on the rice section at the beginning, and then gradually expand around the section to make the diseased part black and easy to break. Early formation of dry white spikes occurred. Only on one side causes the stem to bend. A small brown dot forms at the beginning of the panicle and neck, and the ear and neck become brown after the exhibition, which also results in a dry white ear. The late onset caused the Silicon Valley. Spike or rachis damage caused false spikelets. Grain pods produce brown ovals or irregular spots that make the rice darker. Some glume shells are asymptomatic, and the damage to the cultivars is browned and the seed is carried.
The pathogen Phyricularia grisea (Cooke) Sacc. said Pyricularia oryae Cav. called Pyricularia spp. The sex state is Magnaporthe grisea 9 Hebert) Barrnov. Ascomycete spp. Not found under natural conditions. Conidiophores unbranched, 3-5-branched, extending from host epidermis or stomata, size 80-1604-6(μm), with 2-8 septa, slightly swollen base, pale brown, pale upward, The top of the curve, the upper conidia. Conidia are colorless, pear-shaped, or stick-shaped, often with 1-3 membranes, 14-406-14 (μm) in size, pedicels at base, germ cells on both ends, buds on tip of bud tube Cell, nearly spherical, dark brown, clinging to
Host, born
The invading filaments invade the host tissue. The bacteria can be divided into 7 groups and 128 physiological races.
Transmission routes and pathogenic conditions The pathogens overwinter on straw and rice with conidia and mycelium. The conidia produced in the following year were transmitted to rice plants by wind and rain, germinating and invading the host to spread the disease to adjacent cells, forming a central disease strain. The conidia formed in the diseased part were re-infested by wind and rain. Seeding the seed with bacteria can cause seedling emergence. Proper temperature and high humidity, in the presence of rain, fog and dew, are conducive to disease. Mycelial growth temperature limit 8-37 °C, the optimum temperature 26-28 °C. Spore formation temperature limit 10-35 °C, 25-28 °C optimum, relative humidity more than 90%. Spore germination requires the presence of water for 6-8 hours. Appropriate temperature can form appressorium and produce invading filaments, penetrate the epidermis of rice plants, and spread nutrients between cells. Rainy weather, lack of sunshine or weather when it is sunny, or there are clouds or condensation conditions sooner or later, the condition expanded rapidly. Variety resistance varies by region, season, age, and race. Indica varieties are generally better than glutinous varieties. The resistance of the same variety at different growth stages is also different. The seedlings are susceptible to disease at the 4 leaf stage, tillering stage and heading stage, and the disease incidence is light at the round culm stage. The same organ or tissue is severe at the young tissue stage. The heading was weak when the ear was eared. Partial application of nitrogen fertilizer is beneficial. Deep water irrigation in early or long-term irrigation is poor in root development, and disease resistance is weak.
Control methods (1) Select 2-3 local resistant varieties for local conditions, such as early rice: early 58 and Xiangzao 3, 21, 22, 86-44, 87-156, indica 61, early morning No.39, No.42, No.41, No.39, Boyouzhan, No.81 Zhongyouza, No.2 Zhongsi, No.288 Peiliangyou, Huayingzhan, Shanyou 77; Middle rice: No.1 No.1 bag, Qi Xiu Zhan No. 3, Pei Shan Shan Qing, San Pei Zhan No. 1, Luan Yin Lu Lu No. 1, Ning Lu No. 17,
Ningjing No. 4, Yangfujing No. 2, Shengyou No. 2, Yangdao No. 2 and No. 4, Dongxuan 101, Dongnong 419, Qiyou 7, Jia 45, Xiushui 1067, Japonica 28, 32, 34 No. 36, No. 59, No. 89, No. 89, Teyou 689, No. 397, No. 1 of Yanyou Duoyou, No. 1 of Mancang 515, No. 3 of Quannong No. 3, No. 1 of Jinyou No. 63, No. 1 of Yanyou Duo No. 1; Late Rice: Xiushui 644, Yuanyu No. 4, Jindao 308, Jingdao No. 1, No. 15 Huayuan No. 45, Liaojing No. 244, Shennong No. 9017, Gangyou No. 22, Bizhi No. 37, No. 2 Zaocha, Gang No.2, No.13, No.14 and No.40, Ningshu No.15 and No.16 and other rice blast resistant varieties. Rice drought-resistant seedling varieties Linnao 3, Lindao 5, Jing 31119, and China 91 can be used in the drought-resistant varieties. Dry rice
Zhengzhou Zaoxian and Zhonghua No. 8 disease resistant varieties can be selected during live broadcasting. (2) No disease-free fields, treatment of diseased rice straw, and disinfection source. (3) According to the law of rice need fertilizer, using formula fertilization technology, do wet and dry alternation later, promote rice leaves mature, enhance disease resistance. (4) Seed treatment. Soaked in 56 °C warm soup for 5 minutes. It was soaked for 2 days with 10% of 401 antibacterial agent 1000 times or 80% of 402 antibacterial agent 2000 times, 70% thiophanate-methyl (thiophanate-methyl) wettable powder 1000 times. Can also be used 1% lime soaking, 10-15 °C soaked 6 days, 20-25 °C soaked 1-2 days, lime water layer 15 cm higher than the rice, standing, remove and rinse after 3-4 times. The seeds were soaked in 2% formalin for 20-30 minutes and then covered with film for 3 hours. (5) Drug control Seize the key period, timely medication. Early grasping leaf lice, ç‹ æ²» 穗瘟. Spray 20% tricyclazole (Cdconazole) wettable powder 1000 times or 40% rice bran (Fuji No. 1) EC 1000 times, 50% carbendazim or 50% thiophanate-methyl Wettable powder 1000 times, 50% rice blast Peptide Wettable powder 1000 times, 40% grams Loquat Lotion 1000 times, 50% Imidazole emulsion 500-800 times, 5% Mycotoxin 500 times . The above-mentioned agents can also add 40 mg/kg of kasugamycin or extender to better effect. The leaf temperature should be protected 2-3 times, and the panicle blast should focus on the protection at the heading stage, especially during the booting stage (breaking period) and the full heading period.
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