Smut of Pleurotus ostreatus, a medicinal plant

The scientific name of SagittariatrifoliaL. Commonly known as scissors grass, belongs to the family Alismatidae. The whole herb and corm are used as medicine. It has the effect of clearing heat and stopping bleeding, detoxification and detumescence. It is also a vegetable in autumn and winter. Most of them are planted in rice fields after rice harvest. It is distributed in the north and south provinces of our country.

The main symptoms were damage to leaves, petioles, floral organs and bulbs. The primary yellow to orange-yellow scar spot on the leaf is slightly raised, and the posterior blister spot is withered and yellow and ruptured, scattered with small black powder grains, that is, the spore mass of the pathogen. Some diseased leaves are deformed and twisted. Petiole with globular tumor or black streak. The flower organ is damaged and the ovary turns dark brown. The damage to the corm mostly occurred at the base of the plant and the nodule of the stolon, resulting in the cracking of the stem bark. When the leaf incidence of the plant reached more than 60%, the yield was reduced by 20% and 30%.

The pathogen Doassansiopsishoriana (Pleurotus Henn.) Shen is called Pleurotus ostreatus, which belongs to basidiomycete subphylum fungi. The spore clusters are arranged in one layer, subglobular to ovate, with a size of 77 Mel 218 × 67 Mir 188 (μ m). The outer layer of the sporangium and the sterile cells of the central line, the middle is the spore layer, and the outer layer is composed of 4 layers of colorless polygonal cells. The central cell wall is thin and light olive brown. The spores are tightly bound, long and polygonal, smooth, reddish brown, and the size is 10 mi 17 × 7 mi 10 (μ m).

The pathogens overwintered by spores in the soil or attached to the seed bulb. In the next spring, when the monthly average temperature was higher than 15 ℃, the spores germinated and produced basidiospores, which were initially infected by air flow, Rain Water or field water transmission, and then the spores produced in the disease part were repeatedly infected. The resistance of varieties was different; when nitrogen fertilizer was applied, the disease occurred early and seriously in the fields and continuous cropping fields where the plants grew bright green; high temperature and humidity were the main factors of the disease; and excessive close planting caused the disease seriously.

The control method (1) select the corm from the disease-free field during harvest. (2) change disease-resistant varieties according to local conditions. (3) implement rotation and reasonable close planting. (4) to do a good job in field hygiene, especially after harvest, the sick and residual materials should be collected thoroughly and burned. (5) strengthen water slurry management, avoid long-term deep irrigation, make it dry and wet, promote root development and enhance plant resistance. (6) early spraying 15% triadimefon wettable powder l000 times or 80% antibacterial agent 402 EC 1500 times, 25% carbendazim wettable powder 600x liquid plus 75% chlorothalonil wettable powder liquid, 50% thiram wettable powder 500x liquid, 40% polysulfide suspension 500x solution, 115,200,250 Bordeaux solution, prevention and treatment for 3 times in a row every 10 days or so.