Winter squash suffer from several common problems. If left untreated, these problems can affect the quality of your winter squash. The following is a list of the most common problems associated with winter squash and how to deal with them:
- Gummy Stem Blight (Black Rot): This is a fungal disease that can affect the stems and leaves of your winter squash. It can also spread to the fruits.
Solution: Use a soaker hose or drip irrigation and give your plants plenty of space.
- Downy mildew: This disease attacks most of the plants among the cucurbits. It is caused by the fungus Pseudoperonospora cubensis. If temperatures are cooler and conditions are moist in your region, your squash plants may be at risk. Early signs are yellowing spots on the leaves that may turn brown and fuzzy with time. As the disease progresses, the patches will turn black.
Solution: Give your squash plenty of room to breathe so that air can circulate. Use a compost tea if you expect long periods of cold, wet weather. Ask you nursery about disease-resistant varieties of winter squash.
- Powdery Mildew: Look for a white mold on the leaves of your squash plants. This disease is caused by several different kinds of fungi and will eventually kill the foliage and can affect squash fruit. Powdery mildew occurs in warm rather than cold conditions and high moisture levels will make the problem worse.
Solution: Keep your squash foliage dry. Drip irrigation can help. Compost teas also help to treat this problem. Another organic solution is to apply a mixture of baking soda and water to the foliage (less than an ounce of baking soda per gallon of water). Remove garden debris after you harvest all garden plants.
- Cucumber beetles: Cucumber beetles affect many plants of the cucurbits. They can attack at any point in the growing season. Look for these pests on the fruits and on the vines.
Solution: To treat your winter squash organically, use thick organic mulch, which can keep these pests from laying their eggs. Plastic mulches can also deter their presence. It’s also important to remove garden debris during and after the growing season.
- Squash bugs: Squash bugs are a common problem for cucurbits. The can be a problem throughout the growing season and they canaffect both fruits and foliage.
Solution: Companion planting is an effective solution to squash bugs. Mint, catnip, nasturtiums, and marigolds are excellent companion plants that help repel squash bugs. You can also remove squash bugs by hand. Another unusual option is to encourage the presence of the parasitic wasp Ooencyrtus (spp.) in your garden.
- Other common problems: Winter squash are also threatened by the squash vine borer, the pickleworm, and the seed corn maggot.
Solution: There are a variety of options to treat these pests. See this site for more organic pest control methods.