Squash vine borers are insects that can affect a couple of different members of the curcurbit family. They are a huge pest because a single insect can bring down an entire plant. Control of them can be difficult because timing is very important. Let’s talk about how to identify them and what you can do to keep them taking out your crops.
Squash vine borers (SVB) can be a very aggravating pest to deal with because, often by the time you realize that you have them, it’s too late to do much about it. SVB commonly affect squash and pumpkins. It’s less common on cucumbers and melons. SVB emerge from cocoons in the ground as moths in the summer time. The moths have metallic green wings and reddish-orange bodies with black dots on their back. The moths will mate after emergence and lay eggs at the base of squash or pumpkin plants. The eggs will hatch after a week. The caterpillar that emerges is a whitish cream color. It will bore into the stem of the plant and begin feeding. Sometimes they will bore into the fruit itself. They’ll feed on the plant for 4-6 weeks before returning to the soil to cocoon, and begin the process over again. In Georgia we can get 1-2 generations per year.
The first symptoms that you will most likely see is wilted plants. The plants will wilt because the SVB is putting the plant under stress, preventing it from getting the water and nutrients that it needs. If you look closely at the plant you’ll see small holes with greenish or orange sawdust around it. Eventually SVB will kill the plant.
For small gardens you might be able to carefully remove SVB from the stem if you catch it early enough. You can take a sharp knife and cut up the stem until you find the caterpillar. After removing the caterpillar cover the cut stem with soil. SVB can be controlled by using pesticides, but pesticides are only effective if you apply them while the moths are out. Direct pesticide spray at the base of the plant. You must get good coverage of the vines and stem to have success. Bifenthrin is an effective insecticide against SVB. Please always follow the label when using pesticides.
If you have SVB in your crops one year, it is important to rotate and plant something different in that spot next year, because the SVB will be in the soil. Another strategy if you have a larger garden is to use a trap crop. Trap crops can be used against a number of pests. Basically, the strategy is to plant a crop at least 8-12 feet away from your desired plants. The trap crop will need to be planted earlier than the desired plants. When pests are found on the trap crop you can use a pesticide or mechanically remove the pest. This way you’ll reduce the population of pests that you have, and reduce the amount of pesticide that you apply because you’re focused on spraying the trap crop. Hubbard squash is an example of a plant that can be used as a trap crop.
If you have questions about SVB contact your county Extension Office or email me at Jacob.Williams@uga.edu. On July 25, Union County Extension is putting on a Well Water Program. It will be at 5:30 in the Union County Civic Center. If you would like to attend, please RSVP with Union County Extension Office at 706-439-6030 or email me at Jacob.Williams@uga.edu.