What diseases need to be prevented and controlled in the cultivation of yardlong beans?
What diseases need to be prevented and controlled in the yardlong beans being grown? Please give an introduction. The main diseases of cultivated yardlong beans are as follows: 1. Identification and control of cercospora leaf spot. 1. Symptoms: It mainly damages leaves, stems and vines, and pods. In the early stage of the disease, purple-brown spots appear on both sides of the leaves. After they expand, they become nearly round dark brown lesions, 1~2 cm in diameter...
What diseases need to be prevented and controlled in the yardlong beans being grown? Please give an introduction
The main diseases of cultivated yardlong beans are as follows:
1. Identification and control of cercospora leaf spot
1. Symptoms: It mainly damages leaves, stems and vines, and pods. In the early stage of the disease, purple-brown spots appear on both sides of the leaves. After they expand, they become nearly round dark brown lesions, 1~2 cm in diameter, with indistinct edges. When moist, the surface of the lesions is densely covered with sooty mold (especially noticeable on the leaf surface). In severe cases, it causes early defoliation, leaving only the young leaves at the top; the diseased leaves become smaller, and the pod set of diseased plants is greatly reduced.
2. Control measures
(1) Clean the field. After harvest, promptly remove diseased residues, burn them in a concentrated way or bury them deeply. In the early stage of the disease, promptly remove diseased leaves, which can reduce the spread of the disease.
(2) Strengthen field management. Plant at an appropriate density so that the field is well ventilated and has good light penetration, and prevent excessive humidity. Applying more phosphorus and potassium fertilizer can improve the resistance of the plants.
(3) Chemical control. Spray promptly in the early stage of the disease. You can use 50% carbendazim wettable powder at 500 times dilution, 75% thiophanate-methyl wettable powder at 800 times dilution, 65% zineb wettable powder at 600 times dilution, and 14% copper ammonia complex aqueous solution at 400 times dilution, spraying once every 7~10 days, for 2~3 times in succession.
2. Identification and control of phytophthora blight
1. Symptoms: It mainly damages stems, leaves and pods, and mostly occurs at or near stem nodes, especially near the ground. The diseased part is initially water-soaked, then surrounds the stem with wet rot and constriction, and the leaves and vines above the diseased part die. When humidity is high, the cortex rots and white mold appears on the surface. When leaves are infected, they initially show dark green water-soaked spots, which later expand into round light brown spots with white mold on the surface. When pods are damaged, the diseased part also develops white mold and rots.
2. Control measures
(1) Choose disease-resistant varieties.
(2) Practice crop rotation. Choose well-drained sandy loam for planting, use high beds and deep furrows, and plant at a reasonable density so that it is well ventilated and has good light penetration. Pay attention to timely drainage after rain.
(3) Chemical control. Spray promptly in the early stage of the disease for protection. 58% ridomil mancozeb wettable powder at 500~800 times dilution, 64% sandofan wettable powder at 500 times dilution, and 72.2% propamocarb aqueous solution at 800 times dilution, spraying once every 7~10 days, for 2~3 times in succession, give relatively good results.
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