Yellow Leaves on Butternut Squash

The butternut squash plant (Cucurbita moschat) is a variety of winter squash. Cultivated for at least 6,000 years, the butternut squash is still a popular vegetable.

Cucurbit Yellow Vine Disease

Curcubit yellow vine disease is an infection resulting from the Serratia marcescens bacteria. Squash bugs spread the disease to butternut squash and other plants. Curcubit yellow vine disease clogs the plant's vascular system, causing yellowing leaves and leaf drop. Insecticides prevent squash bug infestations that spread the disease.

Powdery Mildew

Powdery mildew is a disease that causes the leaves on butternut squash plants to turn yellow. The first symptom is small white dots on the underside of leaves, followed by general leaf yellowing and leaf drop. To treat, use fungicides recommended for this particular disease.

Root-knot Nematodes

Root-knot nematodes are microscopic worms that settle in the roots of butternut squash plants. The bugs lay eggs and feed on the roots, resulting in root distortion, yellowing of leaves and leaf drop. A wide variety of nematicides are available to treat root-knot nematode infestations, such as chloropicrin and methyl bromide.

References

• University of Connecticut Integrated Pest Management: Cucurbit Yellow Vine Disease
• University of Florida IFAS Extension: A Series on Diseases in the Florida Vegetable Garden: Squash
• University of Florida IFAS Extension: Florida Crop/Pest Management Profile: Squash
• University of Arkansas Division of Agriculture: Butternut Squash