Acorn squash plant problems are usually caused by pests, diseases or environmental conditions. Common pests that can attack acorn squash are:
Squash bugs are a common pest, and can cause acorn squash diseases. They are usually gray or brown in color, although some are almost black. Squash bugs are usually about the size of a dime and travel in packs. They 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.
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, there are soap sprays and other organic sprays available at most garden shops. Be sure to also 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.
Some common acorn squash 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 acorn squash 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 acorn squash 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 acorn squash plants become infested. 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 start over by planting more seeds.
In an effort combat acorn squash plant problems in our own garden, we've implemented a preventative spray program using a homemade soap spray. We mix together 1 gallon water, 2 tablespoons hot sauce and 2 tablespoons liquid dish soap. We make our own hot sauce with habaneros, but if you want to buy yours, get sauce that is much spicier than regular tabasco or louisiana brands. We also use the cheapest dish soap we can find. We mix this all up in a pressure sprayer and spray all over the plants every 10 days or so or after every heavy rainfall. This mixture won't actually kill any pests, but it does encourage them to move elsewhere and works well as a preventative measure against acorn squash plant problems. In addition, when our squash plants have 3 true leaves on them, we treat the base of the main stem with a small squirt of liquid Sevin pesticide. This wards off the vine borers.
Diseases - If you've ruled out insect problems, you may be dealing with a fungal infection. Some diseases that affect acorn squash plants are wilt disease, powdery mildew, downy mildew and scab disease. These are usually identified by a powder like substance on the leaves or stems. There may also be visible black spots or splotches on the leaves themselves. Most acorn squash diseases can be avoided by choosing disease resistance varieties. They can also be controlled with soap sprays or fungicides that are usually available at most garden centers.
We've had decent results with a homemade fungicide in our own garden. We mix together 1 gallon water, 2 tablespoon baking soda and 2 tablespoon hydrogen peroxide. We mix this in a pressure sprayer and spray it all over the plants to the point of run-off every 10 days or so, or after every heavy rainfall. This mixture works well as a preventative measure against acorn squash plant problems, but in the event we still end up with a fungal infection, we switch to a commercial fungicide product, like Spectracide.
Environment - Sometimes acorn squash plant problems can be attributed to the environment. If the pH in the soil is low, the plants can have trouble absorbing nutrients. Extremely hot or cold weather can impact the plants to the point that they show signs of stress - yellowing leaves, wilting, etc... This can be especially true if you get big temperature swings from day to night. Also, many new gardeners make the mistake of over-watering. If you think your plants need water, spend a minute and dig down about 4 inches into the soil. You want the soil at this depth to be moist, but not soggy. If it soggy, let it dry out for a few days and check again. If it's bone dry, you need to water.
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 acorn squash plant problems.
Click on the following links to learn more about growing acorn squash.
Click here to learn about planting acorn squash
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Click here to learn about harvesting acorn squash
Click here for some of our favorite acorn squash recipes
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