Common diseases and prevention methods of cucumbers grown on the balcony

Common diseases of cucumber farming: downy mildew

It is a fungal disease that occurs in the middle and upper leaves of cucumber. Around 8 am every day, check whether there are water-soaked, polygonal spots on the back of the leaves, and whether there is a gray mold layer on the spots. If these three points are met, it can be diagnosed as downy mildew.

The suitable environment for the disease is a temperature of 16℃~22℃ and a relative humidity of above 83%. The pathogen of this disease is afraid of two things: dryness and high temperature. When dried, the bacteria will die naturally in 3 to 5 days. When the humidity in the greenhouse is high, the temperature can be controlled to 45℃ for 2 hours, and the disease can be easily controlled by spraying appropriate pesticides.

Chemical control: You can choose Anke, Priligy, Metformin, Mancozeb, Imidacloprid, Jinledomil and Amicida. In addition, when preventing and controlling downy mildew, attention should be paid to the simultaneous occurrence of bacterial angular leaf spot. Agents for preventing and controlling bacterial angular leaf spot can be added to the agents for preventing and controlling downy mildew.

Common diseases of cucumber farming: gray mold

Symptoms: Can damage melons, leaves and stems. Diseases caused by fungal infection.

Temperatures around 20°C, insufficient sunlight on cloudy days, relative humidity above 90%, and long condensation times are important conditions for the occurrence and spread of gray mold. If the temperature is above 30°C and the relative humidity is below 90%, the disease will stop spreading.

Chemical control: 1500 times diluted 50% chlorhexidine wettable powder can be used once every 6-7 days, and control 3-4 times in succession. The medicine must be sprayed on the flowers and young melons.

Common diseases of cucumber farming: powdery mildew

Symptoms: Small round white powdery mildew spots first appear on the front or back of the lower leaves, gradually expanding and becoming thick and dense, and soon becoming one piece.

In the later stage of the disease, the entire leaf is covered with white powder, then turns grayish white, and finally the leaves turn yellow-brown and dry. Similar spots as those on the leaves also appear on the stems and petioles, which are densely covered with powdery mildew.

Prevention and control methods: Use 1000 times diluted 20% triadimefon wettable powder, 500-600 times diluted 75% Daktarin wettable powder, 2500 times diluted 10% Seco, or 400 times diluted 2% Jiashoumi, etc., and spray once every 5-7 days.

Common diseases of cucumber farming: bacterial angular leaf spot

Symptoms: Circular or oval water-soaked spots appear on the cotyledons during the seedling stage, which are slightly sunken and then turn brown and wither. During the mature stage, needle-sized water-soaked spots initially appear on the leaves. The spots expand and are restricted by the leaf veins to become polygonal and yellow-brown. When the humidity is high, milky white mucus is produced on the spots on the back of the leaves, which forms a layer of white film or white powder after drying. The spots are brittle in the later stage and are easily pierced.

Prevention and control methods: Spray 5,000 times diluted phytocin, or 500 times diluted 30% copper succinate (DT fungicide) wettable powder, or 400 times diluted 77% copper succinate wettable powder at the early stage of the disease.