It’s getting to the time of year where I’m seeing questions about insect and disease issues in home vegetables and fruits. As you encounter issues in your garden, please feel free to contact us at 706-359-3233 for assistance with diagnoses and treatment of problems- if you wait too long, there’s usually not much we can do. This week, I wanted to share some information about cucurbits- which includes squash, zucchini, pumpkin, watermelon, cucumber, and a few other gourd-type plants.
Preventing disease and pest problems in a home garden requires a lot of moving pieces to come together. First, be sure to select and prepare your garden site well. Look for a well-drained area that is sunny and well ventilated. Run a soil test prior to planting to ensure your pH and fertility are appropriate for the plants you want to grow. If you are an avid gardener, be sure to rotate where your plantings every 3-5 years to help prevent disease and soil-borne problems. When selecting plants for your garden, choose disease-free transplants and seeds, and select varieties that have natural resistance to diseases. Also, be sure to plant your garden at the correct time- most pests are active during the warmest part of the year, so if you can stagger your plantings earlier and later in the summer, you may avoid some of the worst damage. Once your plants are in the ground, follow good watering, weeding, and fertilization practices to encourage healthy growth of your plants and reduce likelihood of pest or disease problems.
When it comes down to it, even the best gardener may experience some pest and disease issues in their garden. For cucurbits, there are a few things that can go wrong- I can’t cover them all today, but the most common issues I see are as follows:
The most common insect pests are aphids, squash bugs, and squash vine borers. Aphids are small insects that are found on new stems and the underside of leaves. They suck the fluid from the plant and cause the leaves to turn yellow and curled. Aphids can be controlled with a strong hosing off or insecticidal soaps. Squash bugs also suck the sap from plant leaves, causing a similar speckled pattern, withering, and death of the leaves. They must be controlled as juvenile insects- once they are adults, control is difficult. The best method of control is to physically remove the insects by hand or to use insecticides. The final pest of cucurbits is the squash vine borer, which digs into the lower stem of squash plants to lay it’s eggs. Those eggs become larvae, which eat through the stem, causing the plant to wilt and die. Control is difficult, so it’s important to prevent this pest with a labeled insecticide.
In addition to pests, there are two common diseases of cucurbits. Powdery mildew is a white, powdery substance that appears on old growth and spreads to the rest of the plant. It is most common in wet, humid conditions, and is best controlled by using resistant varieties. Blossom End Rot is another disease that affects the fruits of the plant, which develop a rotten black spot on their ends. Hot weather, a lack of calcium, and a lack of water all contribute to blossom end rot. Be sure to soil test and follow fertility guidelines as well and providing supplemental water to the plant to prevent this disease.
