Safety management points for the control of leek blight in greenhouse and shed conditions
Damage symptoms: It mainly affects the false stem and bulb, and the leaves, roots, and flower stalks can also be affected. Lesions on affected leaves mostly begin on the lower part, initially producing dark green water-soaked lesions, and when they later spread to about 1/2 of the leaf, the whole leaf turns yellow, droops, and becomes soft-rotted. When humid, grayish-white mold develops on the diseased part. When the false stem is affected...
Damage symptoms:
It mainly affects the false stem and bulb, and the leaves, roots, and flower stalks can also be affected. Lesions on affected leaves mostly begin on the lower part, initially producing dark green water-soaked lesions, and when they later spread to about 1/2 of the leaf, the whole leaf turns yellow, droops, and becomes soft-rotted. When humid, grayish-white mold develops on the diseased part. When the false stem is affected, it becomes water-soaked, light brown, and soft-rotted, and the leaf sheath is easily peeled off. When the bulb is affected, the root disc becomes water-soaked and rots from light brown to dark brown, and when the bulb is cut lengthwise the internal tissue can be seen to be light brown, and growth is inhibited. When the roots are affected, they rot brown, root hairs are noticeably reduced, water uptake is affected, root life span is short, few new roots are produced, growth vigor is noticeably weakened, and life span is shortened.
Control methods:
1. Use 5% chlorothalonil dust, applying 1 kg per 667 sq m each time, and spray once every 7 days for prevention.
2. In the early stage of the disease, use 60% metalaxyl-copper wettable powder at 600 times dilution, or 40% enhanced ridomil wettable powder or metalaxyl-copper wettable powder at 500 times dilution, or 72% Kelu wettable powder or 72.2% Previcur water agent at 800 times dilution, or 50% Anke wettable powder at 2000 times dilution, or 72% Keshuangqing wettable powder or 72% Kekangling wettable powder at 600 times dilution, or 58% metalaxyl-mancozeb wettable powder or 58% ridomil-mancozeb wettable powder at 400 times dilution, or 90% Yishuangling wettable powder at 500 times dilution, or 60% hu·yiphosphorus aluminum wettable powder (DTM) at 100 times dilution, or 72% propamocarb water agent at 800 times dilution, spraying and irrigating once every 7 days, alternating the chemicals for 3 control applications.