What are the white spots on cucumber leaves?

Cucumbers have many diseases, and different diseases have different symptoms. So what causes white spots on cucumber leaves? Let’s learn more about it below.

1. Powdery mildew

Cucumber powdery mildew mainly infects and harms cucumber leaves. In the early stage of the disease, small, nearly circular powdery spots can appear on the leaf surface or back of the leaf. There are more powdery spots on the front of the leaves than on the back. Powdery mildew can occur throughout the growing period. Plants are more susceptible to powdery mildew when the climate is humid and growth is weak.

Prevention and control methods : When using pesticides for prevention and control, you can choose 1000 times diluted 15% oxycarboxin, or 3000 times diluted 40% chlorpyrifos wettable powder , and spray evenly.

2. Thrips

Thrips is an agricultural pest. Adults and nymphs use their rasping mouthparts to tear through tender buds, flower organs, and young fruits of plants and suck the juice inside, causing small spots to appear on the surface, leaves to curl and fade, and tissues to harden and shrink.

Prevention and control methods: In the early stage of insect pests, 2% emamectin benzoate emulsifiable concentrate or 1.8% avermectin emulsifiable concentrate can be used. When the occurrence is serious, 6% spinetoram can be used for foliar spraying.

3. Angular spot disease

When the leaves are infected, needle-sized, water-soaked, transparent spots will appear on the young leaves. As they expand, they will become light yellow spots with yellow halos and turn brown in the middle. The back is grayish white, and as the leaves grow, the diseased part ruptures, which is called irregular perforation.

Prevention and control methods: When the disease begins to occur, spray 2 million units of streptomycin or 500 times diluted 50% thiram wettable powder once every 7 days for 3-4 times.

4. Improper use of drugs

There is a problem with the spraying agent. Unscientific use of the agent will cause damage to the cucumber leaves and cause white spots on the leaves.

Prevention and control methods: When using a high-pressure sprayer to spray pesticides on cucumbers, the nozzle should not be too close to the leaves. High-pressure sprayed liquid is harmful to cucumber leaves. It is relatively safe to keep the nozzle 50 cm away from the cucumber leaves.

5. Temperature is too high

White spots appear on the leaves due to burns caused by high temperatures. This is common in cucumbers grown in greenhouses .

Prevention and control methods: Cucumbers grown in greenhouses need to be ventilated every day in spring as long as it is sunny, and cannot be ignored.

That’s it