There are a number of diseases that go after the leaves of pumpkin plants, and from there to the pumpkin fruit itself. These are called foliar diseases. Quick identification of the problem will guide you to help your plants.
Powdery mildew. It looks just like it sounds. Powdery mildew shows up first on the lower side of the leaves and keeps on moving. It’s a white powdery-looking covering of spores. The spores of powdery mildew can survive in the soil and crop residue and are spread by the wind. Treat it with fungicide as soon as you find it. Remove and dispose of any infected plant material. Do not put infected plants in your compost pile.
Downy mildew. This shows up as yellow spots on the upper surface of the leaves. Cool, wet conditions foster this disease. These spores are spread by the wind, too. Broad spectrum fungicides can help fight downy mildew. If you’re in an area where the weather turns cool and wet late in the growing season, consider planting early season varieties.
Other fungal infections include anthracnose, which starts off as small, light brown spots on the leaves; white speck, which creates tan, diamond-shaped lesions on the leaves and circular white spots on the fruit; and gummy stem blight, which turns leaves and stems brown, eventually killing the plant. The fungus spreads through the soil or the air. Dispose of all diseased plants. Do not put them in your compost pile. And always, always—rotate your crops. Don’t plant pumpkins in the same spot two years in a row.
Now let’s take a look at our insect adversaries, shall we?
Squash bugs. These critters live in large groups and feed on your pumpkin plant’s leaves. Pick them off.
Squash vine borers. First, they tunnel into the plant near the base of the stem. Then they lay eggs. When the eggs hatch (seven to 10 days), the borer larvae eat the delicate inner tissue of the stem, cutting off the flow of water and nutrients to the rest of the plant. If you see something that looks like sawdust at the base of your plant, take a closer look. It is possible to surgically remove the larvae by slicing the stem, removing the larvae, then bandaging the stem with breathable tape from your first aid kit.
Other pumpkin pests include cucumber beetles, aphids, seed corn maggots, and spider mites. Scouting is your first defense against these pests.
The Best Defense is Planning
Pests and disease can really wreak havoc on your pumpkin crop (and that was just a sampling!). But there are some things you can do to give your pumpkins the best chance at making it to harvest:
- Rotate your crops. Don’t plant pumpkins (or pumpkin cousins like cucumbers or squash) in the same place two years in a row. Try to give that area at least three years off from growing cucurbits.
- Survey your soil. Make sure you have good soil drainage and plenty of good air circulation.
- Resist. Pick pest- and disease-resistant varieties to improve your chances of a successful crop.
Have any of these diseases or pests afflicted your pumpkin plants? How did you handle the affliction? Please tell us your best strategies for combating diseases and pests in your pumpkin patch.