You're not alone! Lots of backyard vegetable gardeners have zucchini plant problems - the plants are wilted, bugs are everywhere or things just don't look very promising. Once you are able to diagnose the problem, you're well on your way to solving it.
Most problems with zucchini plants are caused by 3 types of insects:
The most common zucchini plant problems are caused by cucumber beetles. The striped cucumber beetle has black and yellow spots on its back. The spotted cucumber beetle has a yellow back with black spots. They love to chew on young zucchini leaves and stems. Cucumber beetles also carry wilt diseases from plant to plant. Fortunately, these pests can be controlled with common insecticides including sprays and dust. Diazinon and Malathion are common chemicals that will kill cucumber beetles. Apply products that contain these pesticides according to the manufacturer's instructions. Most can be applied soon after the seedlings emerge and throughout the growing season. Organic products including soap sprays are also available at most garden centers.
Vine borers are a common garden pest and can do some serious damage. They will attack any summer or winter squash plant, along with cucumbers and pumpkins. They will bore into the main stems at the base of your zucchini plants, sucking out the juices and eating the plants themselves. Once inside the stems, they will continue eating away at your plants from the inside out. Many times this damage is not noticed until significant and irreversible damage has already been done. The squash growth will suddenly slow and the plant will wilt, shrivel and die. Many backyard vegetable gardeners see the plant wilting and assume that the problem is lack of water. If the plants continue to wilt after a thorough soaking, you're definitely battling vine borers. You will also notice something that resembles a small pile of sawdust at the base of your plants. There are several products on the market that will prevent vine borer infestation. It's important to apply these products before your plants become affected. Read the labels on products that contain Diazinon to make sure that the spray is effective against squash vine borers. Follow the manufacturers directions. Most of these insecticides can be applied soon after the seedlings first emerge. Once the plants stay consistently wilted, you've probably lost the battle. At this point, it's best to pull the plants out of the garden and plant more seeds.
Squash bugs are very common in come parts of the country, and they can really cause quite a lot of zucchini plant problems. They are usually gray or brown in color, although some are almost black. They are usually about the size of a dime and travel in packs. Squash bugs will suck the juices from the plant and will actually attack the squash itself, although they usually lay their eggs on the underside of the leaves. Again, it's easier to prevent a squash bug problem than cure it. Many of the same products that prevent vine borers and cucumber beetles will also prevent squash bug infestations. You can begin spraying soon after the seedlings emerge. By the time the blossoms appear and the plants begin to set fruit, you should have the problem under control. Most of these insecticides are available at most garden centers and should be applied according to the manufacturer's instructions. If you are trying to grow organically, choose pest resistant zucchini varieties and keep your garden free of weeds and other plant debris. You can also cover the stems of the plants with cardboard tubes to discourage pests. Plant your zucchini early in the season as squash bugs tend to be most active in the summer months.
We've had good results in our battle against pests with a homemade soap spray. We mix together 2 gallons water, 4 tablespoons hot sauce and 4 tablespoon liquid dish soap in a 2 gallon pressure sprayer. We mix it up and spray all over our zucchini plants every 10 days or so, or after every heavy rainfall. This mixture doesn't actually kill any pests, but it does encourage them to move elsewhere and works well as a preventative measure.
Zucchini plant problems can also be the result of diseases including wilt disease, powdery mildew, downy mildew and scab disease. If these diseases have affected your zucchini patch, you will notice discolored leaves with splotches on them. Most diseases are controlled by choosing disease resistant varieties of zucchini. They can also be controlled with soap sprays and/or fungicides that are readily available in most garden centers.
We use a homemade fungicide in our own garden and we've had good results with it. We mix together 2 gallons water, 4 tablespoons hydrogen peroxide and 4 tablespoons baking soda in a 2 gallon pressure sprayer. We shake it up and spray it all over our zucchini plants to the point of runoff every 10 days or after every heavy rainfall. On the rare occasion that the plants still develop a fungal infection, we switch to a commercial fungicide product.
Remember, when dealing with most garden pests and diseases, "an ounce of prevention is worth a pound of cure". We hope these tips will help you to avoid most zucchini plant problems.
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Click here to learn about fertilizing and watering zucchini plants
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