What are the key points for pollution-free control of white rust in water spinach?
Symptoms: The lesions appear on the underside of the leaves. On the upper surface of the leaves, pale yellow to yellow spots first appear, later turning brown. The lesions expand, and on the underside of the leaves white raised blister-like spots form, nearly round or oval to irregular in shape, sometimes merging into larger blisters. In the later stage, the blisters rupture and release white, non-functional sporangia. When the leaves are severely affected, the lesions are dense and the diseased...
Symptoms: The lesions appear on the underside of the leaves. On the upper surface of the leaves, pale yellow to yellow spots first appear, later turning brown. The lesions expand, and on the underside of the leaves white raised blister-like spots form, nearly round or oval to irregular in shape, sometimes merging into larger blisters. In the later stage, the blisters rupture and release white, non-functional sporangia. When the leaves are severely affected, the lesions are dense, the diseased leaves become deformed, and the leaves drop off.
Key control points:
(1) Use disease-free seed or treat the seed with 0.3% of the seed weight of ridomil MZ fungicide.
(2) This disease is limited to infecting vegetables in the Convolvulaceae; a 2-3 year crop rotation gives good disease control.
(3) Pay attention to draining waterlogged fields and thinning plants for ventilation.
(4) At the early stage of the disease, spray 48% metalaxyl-mancozeb wettable powder, 40% metalaxyl-copper wettable powder, or 64% Sandofan wettable powder at 600 times dilution, or 72.2% Previcur N aqueous solution at 800 times dilution, once every 7-10 days, for 2-3 consecutive applications.