Integrated control methods for downy mildew in autumn garland chrysanthemum
Downy mildew in garland chrysanthemum mainly damages the leaves. In the early stage of the disease, pale yellow nearly round or polygonal lesions appear on the old leaves in the lower part of the plant, gradually spreading to the middle and upper parts of the plant; in the later stage the lesions become yellowish brown, and when the disease is severe the lesions merge into one patch and the leaves turn yellow and die. When humidity is high, white mold develops on the underside of the lesions. The pathogen infects...
Planting density should be reasonable, avoiding excessive dense planting; apply heavy base fertilizer, increase organic fertilizer, control the amount of nitrogen fertilizer, and prevent excessive vegetative growth; do not use flood irrigation, and drain promptly after heavy rain. In the early stage of the disease, you can choose 58% metalaxyl?mancozeb wettable powder at 500 times dilution, or 64% oxadixyl?mancozeb wettable powder at 500 times dilution and other sprays, spraying once every 7-10 days, for 2-3 consecutive sprays. For plots cultivated under protective structures, chlorothalonil smoke agent can be used for fumigation control.