Symptom Identification and Control Methods of Brown Spot Disease in Water Spinach
Symptoms initially appear as small yellowish-brown spots, which later expand into circular to oval, or irregular dark brown lesions, 4-8 mm in diameter, with distinct edges. In severe cases, the lesions merge with each other, and the diseased leaves turn yellow, wither and die. Disease conditions: It is prone to occur in rainy and humid weather or during off-season cultivation. Control methods...
Symptoms: Initially small yellowish-brown spots, which later expand into circular to oval, or irregular dark brown lesions, 4-8 mm in diameter, with distinct edges. In severe cases, the lesions merge with each other, and the diseased leaves turn yellow, wither and die.
Disease conditions: It is prone to occur in rainy and humid weather or during off-season cultivation.
Control methods
Chemical control: (1) Treat seeds with 35% metalaxyl seed dressing agent at 0.3% of seed weight.
(2) At the early stage of the disease, spray 58% metalaxyl? mancozeb wettable powder at 500 times dilution, 50% metalaxyl-copper wettable powder at 600-700 times dilution, or 64% oxadixyl? mancozeb wettable powder at 500 times dilution, 40% fosetyl-aluminum (Shuangyiling) wettable powder at 250-300 times dilution, 72.2% propamocarb aqueous solution at 800 times dilution, 50% prochloraz wettable powder (Baoliduo) at 35-75 g/mu, 70% propineb wettable powder (Antaisheng) at 150-220 g/mu, 25% azoxystrobin suspension concentrate at 25-30 g/mu, 64% mancozeb? metalaxyl wettable powder (Fumiduo, Waier, Caifukang) at 100-150 g/mu, 50% iprodione wettable powder (Puhaiyin) at 50-100 g/mu, 10% difenoconazole water-dispersible granules (Shigao) at 35-50 g/mu, 25% metalaxyl? myclobutanil wettable powder (Sike) at 100-140 g/mu, 25% mancozeb? carbendazim wettable powder at 100-200 g/mu, 5% hexaconazole suspension concentrate (Anfu) at 60-100 g/mu, 40% flusilazole emulsifiable concentrate (Fuxing) at 10-15 g/mu, once every 7-10 days, for 2-3 consecutive applications.
Agricultural control
(1) Use disease-free seeds.
(2) This disease is limited to infecting Convolvulaceae vegetables; after 2-3 years of crop rotation, the control effect is good. (3) Pay attention to field drainage and thinning plants for ventilation.