Mungbean powdery mildew
Symptoms damage the leaves, stems and English. In the early stage of the disease, a white powdery substance was generated on the surface of the diseased part, and the spotting began. Afterwards, it spread to the whole leaf. In the later stage, many small black spots were produced, namely the closed capsule of pathogenic bacteria. In severe cases, the leaves turn yellow and fall off early.
The pathogen Erysiphe polygoni DC. is known as Erysiphe graminis, belonging to Ascomycete spp. The mycelium was born on both sides of the leaf and a few were on the back of the leaf. Conidiophores are cylindrical with a size of 30.5 to 43.215.2 to 17.8 (μm). Ascidian fruit spherical, dark brown, diameter 95-122μm, wall cell shape is irregular. Attachments 13–37 roots, unbranched or irregularly branched, a few 1-2 bifurcate-like branches, curved or curved, 75 to 158 μm in length, 0.5–1 times the diameter of the fruit of the ascus, up and down Near uneven or partial uneven thickness. Ascospora 4-8, short ovate to long ovate or irregular ovate, individual subglobose, stalk obvious or absent, size 53.3-71.133-45.7 (μm). Ascospores contain 2-4 ascospores, oval-ovate, individual ovate, with yellow, size 20.3-3012.7-15.2 (μm).
The transmission route and the disease conditions were overwintering on the surface debris in the closed capsular shell, and the infestation of the ascospore was suitable for the initial infection in the following year. After the onset of disease, the diseased part produces conidia, which is reinfected by airflow and repeated infestation after repeated infections. In the case of moist, rainy or watery fields, plants are prone to morbidity; under dry and rainy conditions, the plants often grow poorly, and the disease resistance is weak, but the pathogenic conidia can still germinate and invade, especially dry and wet alternate The disease is expanding and the disease is heavy.
Control methods (1) Selection of powdery mildew resistant varieties. (2) Dispose of the diseased body promptly after harvest and concentrate it deeply or burn it. (3) Advocate the use of compost made from fermented bacteria or fully decompose organic fertilizer, adopt formula fertilization technology, strengthen management, and increase resistance to disease. (4) Early stage of onset of spraying 2% Wuyimycin 200 times solution or 10% Shiliangling Slurry 1000 times solution, 60% antifungal mold No. 2 water-soluble powder 1000 times solution, 30% basic copper sulfate suspension agent 300-400 Diluent, 20% triadimefon EC 2,000 times, 5% Le Bibin wettable powder 1000-1500 times, 12.5% ​​Super Poly wettable powder 2000-2500 times, 25% enemy demulsifiable oil 4000 times, 40% Fuxing Star EC 9000 times.