How to Treat Cucumber Diseases? A Complete Guide to Prevention and Control Methods

Cucumber is a common fruit that can also be eaten raw, and it is a favorite of many people. Farmers with growing experience know that cucumbers are prone to diseases. So, how do you treat cucumber diseases?

1. Cucumber downy mildew

It mainly damages the leaves. When seedlings are infected, round bright yellow spots appear on the upper surface of the cotyledons, peaking during the full fruiting stage. Water-soaked spots first appear on the leaves, then expand and merge into large spots. In severe cases, the diseased leaves curl, turn yellow-brown and dry up, and dense purple-gray to purple-black mold grows on the spots on the underside of the leaves.

Prevention and control methods:

1. Improve cultivation techniques

Measures such as growing on high ridges with plastic film mulch combined with drip irrigation, applying more base fertilizer, topdressing nitrogen fertilizer during the fruiting stage, and preventing flood irrigation can all reduce the incidence of the disease.

2. Strengthen chemical control

After transplanting, strengthen forecasting and monitoring; once the disease is found, apply pesticide promptly for control;

Common control agents: 75% chlorothalonil wettable powder at 500 times dilution or 70% mancozeb wettable powder at 500 times dilution, sprayed on a sunny morning, once every 7-10 days, for 3-4 consecutive sprays.

2. Cucumber Fusarium wilt

Cucumber Fusarium wilt, also known as vine splitting disease, is a serious disease of cucumbers in protected cultivation, causing even greater damage in continuously cropped greenhouses and glasshouses. In general, the incidence rate in greenhouses with a short planting history is 5%-10%. As the number of consecutive cropping years increases, the disease worsens, with a severe incidence rate of more than 50%, and in some cases the crop cannot be grown at all.

Prevention and control methods:

1. Seed disinfection

Before sowing, soak the seeds in warm water at 55 degrees for 15 minutes, then sprout and sow; or soak the seeds in 50% carbendazim wettable powder at 500 times dilution for 60 minutes, then sprout and sow; or bake dry seeds at a constant 70 degrees for 72 hours, then sprout and sow after cooling.

2. Strengthen cultivation management

Use high ridges and plastic film mulch for cultivation, apply sufficient decomposed base fertilizer to enhance plant resistance; avoid flood irrigation during the fruiting stage, and take good drainage measures during rainy weather.

3. Soil disinfection in greenhouses

For each mu, mix 50% carbendazim wettable powder with 30kg of fine dry soil, then apply it in furrows or planting holes at transplanting.

3. Cucumber powdery mildew

Cucumber powdery mildew mainly damages the leaves, petioles and stems, and the fruit is generally not affected; in the early stage of the disease, small white, nearly round powdery spots appear on both the upper and lower surfaces of the leaves. As the disease spreads, they cover the entire leaf surface, later turning gray-white. In severe cases, the leaves turn yellow, curl up, and the plant dies.

Prevention and control methods:

1. Chemical control

In the early stage of the disease, use 25% triadimefon wettable powder at 2000 times dilution or 50% thiophanate-methyl wettable powder at 800 times dilution, spraying once every 7-10 days, for 2-3 consecutive sprays.

2. Strengthen cultivation management

Avoid growing flowers that are susceptible to powdery mildew in the greenhouse; when applying base fertilizer, apply phosphorus and potassium fertilizer reasonably;

Strengthen ventilation and light penetration in the greenhouse and air exchange indoors to reduce humidity.

The above are three common cucumber diseases. In addition, there are also brown spot, bacterial angular leaf spot, anthracnose, damping-off, Rhizoctonia rot, Phytophthora blight, gray mold, target spot and other diseases. These diseases occur mainly because as the weather warms and temperatures gradually rise, improper management creates a high-temperature, high-humidity environment. The symptoms of these diseases are very similar.