A Detailed Guide to the Prevention and Integrated Treatment of Spinach Downy Mildew
The disease is caused by a fungus called spinach downy mildew (Peronospora farinosa f. sp. spinaciae). It mainly affects the upper surface of the leaves; the lesions are pale yellow, irregular in shape, vary in size, measure 3-17 mm in diameter, and have indistinct edges. After the lesions expand, they join together into patches, and in the later stage turn brown and die, while a grayish-purple mold layer forms on the lesions on the underside of the leaves. The disease spreads from the outer leaves...
The disease is caused by a fungus called spinach downy mildew (Peronospora farinosa f. sp. spinaciae). It mainly affects the upper surface of the leaves; the lesions are pale yellow, irregular in shape, vary in size, measure 3-17 mm in diameter, and have indistinct edges. After the lesions expand, they join together into patches, and in the later stage turn brown and die, while a grayish-purple mold layer forms on the lesions on the underside of the leaves. The disease gradually spreads from the outer leaves to the inner leaves, and from the lower part of the plant upward. In dry conditions the diseased leaves turn yellow and wither, while in high humidity they mostly rot, and in severe cases the leaves of the whole plant turn yellow and die. The control methods are as follows:
I. Strengthen cultivation management: plant at a reasonable density, irrigate scientifically, and reduce field humidity.
II. Choose disease-resistant varieties: our company now offers spinach varieties such as Aiduoshou, which is resistant to downy mildew physiological races 11-13, Quanneng, Suxianfeng, and Kangbing 99Y large-leaf spinach, all available for you to choose from.
III. Chemical seed dressing: if the seeds carry the fungus, dress the seeds before sowing with 50% thiram wettable powder, at a rate of 0.4% of the seed weight.
IV. Remove diseased plants: in early spring, if diseased plants are found in the spinach field, remove them promptly, take them out of the field, and burn them.
V. Chemical control: in the early stage of the disease, spray 40% fosetyl-aluminum wettable powder at 200-250 times dilution, or 58% metalaxyl-mancozeb wettable powder at 500 times dilution, or 72.2% propamocarb aqueous solution at 800 times dilution, once every 7-10 days, for 2-3 consecutive applications.