Identifying the Squash Vine Borer and Squash Vine Borer Damage
How to Identify Squash Vine Borers
- Eggs: The eggs are tiny, flat, oval, and brown. The eggs are laid around the bases of squash plants.
- Larvae: If you slit open a stem lengthwise with a fine, sharp knife, you will see the borer larva, which has a fat, white, wrinkled body and brown head; it can grow to about an inch long.
- Moth: The adult squash vine borer is a moth about 1/2 inch long. It has a gray or black body, marked with orange-red on its abdomen, legs, and head. The hind wings are transparent, and the front wings are metallic green.
Identifying Squash Vine Borer Damage
- First, the leaves of the plant will likely start to wilt inexplicably.
- Look for holes at the base of the plant and green or orange-yellow sawdust-like 鈥渇rass,鈥 which is fecal matter (poop!)
- Squash vine borer larvae feed on the material inside the stems of the plants. The stem will start to rot at the site of the feeding first.
How to Prevent Squash Vine Borers
As with most pests, prevention is key.
- Sometimes, the best solution is to start your squash as early as possible. This way, plants will be strong enough to withstand any mid-summer attacks, and you may even be harvesting before squash vine borers become active. If you plant early, you may need to be prepared to cover your plants in case of late frost.
- Do not plant squash in the same area two years in a row. Squash vine borers overwinter in cocoons in the soil. Also, clean up and dispose of ALL plant debris in the fall.
- Dispose of the squash plants as soon as they are finished for the season. In the fall and spring, till the soil to get rid of overwintering pupae.
- Physical barriers can be an effective means of keeping squash vine borers at bay:
- Cover the plants鈥 stems with a barrier, such as strips of nylon stockings or aluminum foil, to prevent egg laying.
- Before flowers appear on the plants, use row covers to keep squash vine borers away. The covers will need to be removed for pollinators, eventually. This will not only give you a head start over pests, but protect your plants from strong heat and frost.
- Adding beneficial insects such as parasitic wasps to your garden prior to the vine borer鈥檚 egg stage can be helpful, as these wasps are the borers鈥 natural enemies.
- If you give up on zucchini, which is susceptible to vine borers, try growing a squash that鈥檚 more resistant. Butternut squash and Cucuzzi (Lagenaria siceraria)鈥攁lso known as the snake gourd鈥攖end to be resistant to squash vine borer attacks.
- Plant extra squash for the pests! This pest is around for only 6 to 8 weeks and can only eat so much (or so we think!), so making sure you have plenty of plants to spare can help you avoid a total loss for the season.
How to Get Rid of Squash Vine Borers
If you鈥檙e already seeing signs of squash vine borers, use these methods to get rid of them or at least minimize their damage to your crops.
- If you catch them VERY early, you can manually remove the squash vine borer. Locate the entry point of the larvae, then slit the stem lengthwise with a fine, sharp knife to remove the larva by hand. One plant can house several larvae. Carefully remove the larvae without doing more damage to the plant. After removal, cover the slit stem section with moist soil above the point of injury to promote the formation of secondary roots. Also, extra rich soil near the vines helps to reroot.
- If you can find the entrance holes and 鈥渟awdust,鈥 try inserting a wire and threading it through the stem for some distance to kill the larvae inside.
- Sprinkle diatomaceous earth around the stalks when the squash vines are small, or the threat of squash vine borers is high (early to mid-summer). Reapply after rain. Also, build up the soil around the vines. Or, sprinkle black pepper around the plants as a defense.
- If possible, catch and destroy the moths at twilight or in the early morning when they are resting on the upper leaves of the plants.
- There are insecticides that work, too, but timing is critical; they are only truly effective when applied at the time when eggs are hatching.
- The bacteria Bacillus thuringiensis v. kurstaki (鈥淏t鈥) is a natural insecticide that can be injected into and applied to the squash stems.
- Insecticides containing the ingredients carbaryl (Sevin) or permethrin will work on squash vine borers, too. Always be sure to read labels and warnings carefully before application of any insecticide.
- Consult your local cooperative extension service for advice on appropriate chemical controls.
- Trap the adult orange moths with yellow sticky traps and yellow-colored bowls of soapy water.
- A trap crop of very early-planted Hubbard squash can be used to alleviate pest pressure on other squash.
- An old folk remedy from The 1963 Old Farmer鈥檚 蜜桃恋人 says that wood ashes were effective against the squash vine borer.
Learn about another main squash and zucchini predator: the squash bug.
Do you have any tips for controlling these pests? Let us know in the comments below!
Catherine Boeckmann
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Remove it. BTW, did you know putting those grubs on a fish hook will catch dinner for you?
Seminole pumpkin are resistant.
Also, With Yellow Crookneck Squash if you can keep it alive long enough it will off-shoot another plant. Mound soil on the 鈥渧ine鈥 where it will root. If the first plant is killed the 2nd one can still live or 3rd, 4th, 5th, etc. One year I had a plant with 6.
The best defense I have found is to mound soil up the main stems as the plant grows. Renew mound after a hard rain.
The best defense I have found is to mound soil up the main stems as the plant grows. Renew mound after a hard rain.
We have both yellow squash and zucchini for the first time in years. In the past, both were attacked by squash bugs and then finished off with vine borers. This year, new locations were selected and an inexpensive bolt of tulle was purchased to create 'row covers'. The 54" width was not enough, so edges were stapled together around some string and left over stakes provided support. Then, duck tape was used to remove some early squash bug eggs. Hand pollination is required, but we finally have enough for ourselves and enough to share. I felt strangely happy when I found eggs deposited on the outside of the tulle! The bugs gave it a good try!
Every summer since I moved to Western Massachusetts, which has been the past 6, my squash plants have been destroyed by these pests. I got one zucchini out of 6 plants a couple of weeks ago, and not one since. The plants still look healthy and blossoming, but aren鈥檛 producing; and have the tell tale 鈥渇rass鈥 on the stems where the vine borers have entered the vine. I鈥檓 wondering if I should replace the soil in my garden? Or, should I make container garden beds? It鈥檚 so disappointing to watch all of your hard work and money and time get destroyed by these little jerks!
Zone 7/ OKC. I am still finding adult moths on my plants as of tonight (July 24th 2019) I was under the impression that the life cycle was limited to early summer but I lost all of my summer squashes planted in April/May and 3/4 of my cantaloupes planted in early July are already infested. I'm going to try the yellow traps next.
Don't give up! Slice open the base of the stem and pull those little jerks out! Place them in a mason jar of water with some dish detergent, they will die. Then press the two side of the stem back together and bury it with soil. Your plant will feel better and start producing within days!
I also am experiencing the borer moths in Late July, in Northeast Massachusetts. I tried the yellow water, but only found five dead bees. So I won't be doing that again as they are definitely not my target
