Early summer is the time to harvest from the garden, and to watch carefully for pests and disease. We have been harvesting cucumbers for a few weeks. It is important to check them every day or every other day and pick the cukes before the get too big. If they stay on the vine too long, cucumbers will develop a bitter taste, turn yellow and develop large, unappetizing seeds. Also, frequent picking of the cukes will keep the vines producing more. This time of year, we will also inspect fruit for pickleworms and other insects. If you see a hole in the cucumber with a clear jelly surrounding it, you a pickleworm. We will also inspect the leaves for signs of mildew. So far, our cucumbers have not had any problems, and continue to produce lots of cukes.
Squash is another plant that we should inspect for pests and disease. If you remember, we planted our squash early in the spring to try to get as much yield as possible before the plants start to fail. We are starting to see signs of both insects and disease. Vine borers are insects that eat the vines from the inside. They are difficult to control with pesticide, since they are inside the plant, and pesticide is applied to the outside of the plant. Vine borers often eat through the entire vine, which ends up killing the entire plant.
Powdery mildew is a common fungal disease on squash leaves. It is a white powdery growth on the leaves on the plant. Powdery mildew occurs during dry weather with high humidity. It spreads when the fungus produces spores that are dispersed into the air. When they land on suitable host, like squash or cucumber leaves, they grow. It starts as small powdery white circles, but if left unchecked will spread. Powdery mildew does not impact the squash, but it will harm the leaves to the point where they will fall off the plant. Enough dead leaves will slow down and eventually kill the plant.
A first step in slowing down powdery mildew is to cut off infected leaves. A preventative fungicide can also be applied to try to slow down the infection.
This time of year, however, it often becomes overwhelming to fight pests and disease that attack squash so quickly. For many, this is the time to be thankful for the squash already harvested and rip up the plants for the season. In another month or so, it will be time to start planting for the fall garden. Make sure you pull up plants infected with powdery mildew and remove them from the garden. Also, when planning for future gardens, think about planting varieties that are resistant to powdery mildew.