My Cucumbers are Turning Yellow & Dying

Cultivation

• Cucumber seeds may be planted as soon as the soil warms in spring. Seeds should be planted only 1/2 inch deep. Improper cultivation can lead to the yellowing of leaves and fruits. Cucumbers requite large quantities of moisture to grow properly, particularly when the fruits appear. Soil deficiencies may also lead to yellowing of leaves and fruits. Chlorosis occurs in areas with poor drainage and soil that lacks appropriate amounts of manganese and/or zinc. Chlorosis may be fixed by amending the soil to improve nutrient quality or drainage.

Disease and Virus

• The fungal disease anthracnose is common in moist, warm weather. All parts of the cucumber may be damaged by the anthracnose, though it appears in mature leaves first as yellow spots. As the disease progresses, infected areas turn brown, then black. Crop rotation and fungicides help control anthracnose. Cucumber mosaic virus will make the knobs of the cucumber fruits turn yellow. Mosaic viruses spread rapidly and may strike peppers, squash and many other garden plants. Mosaic viruses are carried by aphids. Use pest management practices and pesticide to prevent mosaic virus.

Mildew

• Powdery mildew starts out as white spots that look fuzzy and powdery on leaves. It appears in middle and late summer during hot, dry weather. Powdery mildew spreads and progresses quickly, turning leaves yellow before they wither and drop from the plant. Powdery mildew rarely affects cucumber fruits. Downy mildew, a similar fungus, creates gray spots on plants before yellowing is noticed.

Pests

• Aphids may spread cucumber mosaic virus to cucumbers, which turn yellow and die as a result. Make a homemade pesticide of diluted liquid soap to rid cucumbers of aphids. Squash vine borers are more difficult to kill. Cucumbers being damaged by squash vine borers have drooping foliage and a yellowish tint to the fruits and leaves. Squash vine borders are capable of killing cucumbers overnight. The insects appear in the garden in late June and early July. Protect cucumbers from squash vine borders with row covers that prevent them from laying their eggs at the base of the plants. Cucumbers infected with borers should be removed from the garden immediately.