Squash Vine Borer (SVB) is a common pest that can wreak havoc on your CT garden. This red-orange and black winged insect emerges in early to mid-summer and lays its eggs at the base of squash stems. When those eggs hatch, larvae emerge and bore their way into the plant stem, continuing to eat your squash plants from the inside out until they are ready to pupate. By the time you notice the damage, it's often too late. But don't despair! There are strategies you can employ to protect your garden.
Understanding the Enemy
The SVB is particularly drawn to Cucurbita pepo, which includes zucchini and summer squash. These plants have thin, hollow stems, making them easy targets. Pumpkins fall into this category as well, though they have a slight advantage due to their tendency to vine out and lay roots along the stems touching the soil surface. Cucurbita maxima, encompassing winter squash like giant pumpkins, Kabocha, and Blue Hubbard varieties, is also susceptible but less preferred. The most resistant species is Cucurbita moschata, which includes butternut, honeynut, and crookneck squashes. Their thicker, more succulent stems make them less appealing to the SVB.
Defensive Strategies
Select Resistant Cultivars: Knowing which squash types are common targets can help you make informed decisions. If you have a history with these insects, consider planting resistant varieties like C. moschata.
Rotate Planting Sites: This is crucial! These insects overwinter as pupae in the soil and emerge as adults in June-July. Planting in the same spot each season is like inviting them in for a feast. Move your planting site and add a protective row cover as soon as you plant. Remove the row covers once male and female flowers emerge to allow pollinators access.
Preventative Measures: For those unable to rotate, don't despair. Avoid using row covers as they can trap the pests. Try placing aluminum foil around the first couple of inches of stem at the soil line. Treating the base of plants with a preventative pesticide may also be effective, but be cautious of its impact on pollinators.
Early Detection is Key
Start scouting for adults in mid to late June. Check the base of stems for eggs and early boring damage. You might even spot the adult insects flying around. Symptoms like wilting often begin in late June and become more common in July. If you're feeling brave, you can carefully slice into the stem to find the larvae. Vining squash species may recover if the pest is removed and buried in the soil, allowing new roots to take over. Alternatively, remove affected plants entirely and dispose of them to break the life cycle.
A Second Chance
Since the SVB typically has one generation per year, your hard work pays off. Managing the SVB in early summer ensures your squash can grow healthy for the rest of the season. Plant a second crop of summer squash in July, after the adults have finished laying eggs. This second crop should be unaffected and produce delicious squash for your family.
Remember, early detection and proactive measures are key to keeping your CT garden SVB-free. Happy gardening!
