Cucumber Plant Leaves Turning White. Cucumbers belong to the cucurbit family, a family that also includes squash, melon, pumpkin and watermelon. The leaves of the cucumber begin to wither and then fall off prematurely.
The fungus may colonize the leaf stalks (petioles) and stems. All of these garden plants are susceptible to a damaging fungal disease called powdery mildew, which turns the leaves of the plant white with spores before eventually killing them. This fungal disease may cause poor growth of the fruits specifically if the infection is severe.
It’s important to recognize the problem quickly so you can take the appropriate action.
Cucumber plants often suffer from powdery mildew disease. If you noticed a white coating on the leaves and stems of a plant, it is affected by powdery mildew. In a greenhouse, plants are exposed to high levels of filtered or artificial light, so they grow leaves that are good at soaking up those. Cucumber leaves turning white after being transplanted may indicate root or stem damage.