I read somewhere one time that cucumber and cantaloupe leaves turn brown due to age. Like the first leaves when the plants first start growing turn brown and die off. I'm wondering is that what is going on with my cucumber and cantaloupe Vines? Thank you
Cucumber and Cantaloupe Leaves
Certified GKH Gardening Expert
Some leaves can be damaged by movement in the garden or even wind and sunshine.
Look for pests, they can be hard to find; but I do see some possible pest damage on the leaves.
This could also be a leaf spot fungus; it can be caused by overhead watering or even poor air circulation.
Cercospora Leaf Spot
Cercospora leaf spot is generally limited to the leaves but can affect petioles and stems in a favorable environment. Dark spots are usually first seen on older leaves and are circular to irregularly shaped, with lighter colored centers and darker margins. Tissue surrounding the spots often yellows. Centers of the spots may drop out, leaving holes in the leaves. As lesions expand they often merge, blighting entire leaves. Lesions don't form on the fruit, but if disease is severe enough for defoliation to occur, fruit may be smaller and of a lesser quality.
The fungus overwinters in crop debris and on weeds in the cucurbit family. The spores can be wind-blown or carried in splashing water. Free water on leaf surfaces is required for infection, which is favored by temperatures of 79 - 90 degrees F. The disease progresses rapidly at these temperatures and infections of new leaves can occur every 7 - 10 days.
Prevention & Treatment: To manage this disease, avoid overhead irrigation if possible, or water in the early morning hours when leaves are already wet with dew. Remove and destroy old cucurbit vines and residues, since this is where the fungus survives the winter. Keep the garden well weeded to prevent a buildup of humidity in the canopy and take special precautions to destroy weeds in the cucurbit family, such as bur cucumber and coyote gourd. Rotate away from cucurbits (melons, squash and cucumber) for 2 - 3 years, if possible. If the disease is severe enough to warrant the use of fungicides, several are available for home garden use.