Protect Your Crops From Squash Bugs and Squash Vine Borers

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Using squash as a trap crop

Appearing out of nowhere in early summer, the two worst squash pests in North America are squash bugs (Anasa tristis) and squash vine borers (Melittia cucurbitae). Both pests are native, and have probably been sabotaging squash and pumpkins for thousands of years, or as long as these crops have been grown by humans.

Dull gray, hard-backed squash bugs weaken plants by sucking plant juices and hatching dozens of young, and they have been found to transmit the bacteria responsible for cucurbit yellow vine disease, which causes affected plants to turn yellow and die. The damage done by squash vine borers is different but with similar results. These moth larvae feed inside the main stems of summer squash, pumpkins, and thick-vined winter squash classified as Cucurbita maxima. After a couple of weeks of secretive feeding, the base of the plant breaks off and the plant usually dies.

Squash bug

Common Cures for Squash Pests

There are dozens of interventions to try to manage these pests. One of the best involves growing a few ‘Blue Hubbard’ plants as a trap crop, because both squash bugs and squash vine borers have been found to prefer it over other varieties. The trick is to start the trap crop plants early and have them out in the garden when the pests emerge in early summer, and to delay the planting of susceptible squash until the trap plants have time to grow.

You can keep your ‘Hubbard’ or other trap plants in containers to make them easy to handle, or try my low-labor method. In spring I put a few ‘Yellow Crookneck’ seeds in a protected spot near my compost pile, and encourage two plants to grow. ‘Yellow Crookneck’ is not as attractive to squash bugs and borers as is ‘Blue Hubbard’, but it is very well liked and I always have seeds. My trap plants are growing well by the time I plant my summer squash, and serve as indicator plants when squash bugs become active.


Adult squash bugs spend a lot of time hanging out on squash leaves, looking for love, and then the females head to leaf undersides to lay groups of shiny brown eggs. I allow this activity to proceed on the trap plants, and meanwhile do my best to hand pick the few squash bugs that appear in my cultivated squash, located many rows away. When the trap plants have squash bug eggs on many leaves and some of them have started to hatch, I quickly chop up the plant with a spade and stuff it down my stationary composter.

This simple trapping method has kept squash bugs from becoming a serious pest in my garden, though I still patrol my plants daily to rub off eggs with a wet finger, or squash adults I manage to catch (no pun intended!). In years when squash bugs get ahead of me, I place old boards under the plants, and gather squash bugs found hiding beneath them first thing in the morning.

In mid fall, after the first frost, place a small pumpkin where squash grew that year. On warm days squash bugs will come out and gather on the pumpkin, where you can collect them in soapy water. I have had excellent luck reducing squash bug populations with this fall trapping method.

Adult squash vine borer (left) and larva (right)

Squash Vine Borer Barriers

Sneaky squash vine borers hatch from tiny brown eggs laid by a large red and black moth on the basal stem of squash plants. If you see borer damage year after year, you should wrap the base of each plant with strips of aluminum foil or cheesecloth, which often give good protection. But if it’s too late for prevention and you see holes near the base of the plant surrounded by sawdust-like frass (borer doo), your options are limited because you can’t poison or hand-pick pests from inside the stem.

You may be able to kill or injure them. The borers are usually feeding about an inch above the frass hole, and I have maimed quite a few by sticking pins through suspicious stem sections, voodoo-style. More aggressive removal by slitting the stem with a knife and fishing out the borers with tweezers can work if you cover the surgical wound with soil. You also can inject Bacillus thuringiensis into the stem using a syringe, which stops borer feeding and buys your plants some time.

Pumpkin ‘Long Island Cheese’

With winter squash it’s simple to sidestep squash vine borers by growing butternuts and pumpkins classified as Cucurbita moschata, which are non-preferred by squash bugs and seldom bothered by borers because the stems are so thin that they make poor food plants for borer babies. My current favorite pumpkin is ‘Long Island Cheese,’ because the bugs leave it alone, making it easy to grow carefree bumper crops.

Original article published 6 July 2017.

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Show Comments


"This year I made a "tent" for my summer squash out of window screen. So far, so good. Not a squash bug nor a borer in sight. By now my plants would have been in the compost pile. Just make sure you seal it very well so that they can't get in at any seams. I folded mine over a couple times and closed it with a clothes pin. Seems to be working well, so far. About to harvest my first squash today!"
Sadaajit on Friday 7 July 2017
"what about delaying planting to avoid the egg laying part of their cycle"
chris on Saturday 8 July 2017
"This can be done in some parts of the country. However, here we have two cycles of borers, so you usually plant and lose both sets of plants. The screen is keeping out everything, so I have to hand pollinate, but it's worth it to actually get some squash before the plants are killed by the borers."
Sadaajit on Saturday 8 July 2017
"Chris, you are right about delayed planting. When you rush to plant in spring, the squash bugs tend to be worse than if you wait until early summer to grow summer squash. Part of the reason my trap crop is effective is that the main crop goes out late. "
Barbara Pleasant on Monday 10 July 2017
"when injecting bt , what strength do you use?"
Leah Casady on Tuesday 26 June 2018
"Leah, I would use the dilution rate on the package because it is known to be effective and safe to handle. If you are mixing a powder into water, and no directions are given, 1 teaspoon per cup of water is a good estimate."
Barbara Pleasant on Tuesday 26 June 2018
"I have had decent luck cutting off leaves that are obviously harboring borers and doing a dance upon them and also covering the base of the plant with soil when I see evidence of borers."
tam on Tuesday 10 July 2018
"How far away should I plant "trap" hubbard squash plants from the garden?"
Jennifer on Saturday 13 April 2019
"Jennifer, the best practice is to plant the trap crop on the outer edge of the garden so it can intercept incoming insects in search of host plants. If one edge of your garden borders on brush, woods, or other sources of winter shelter, that would be the best location for your trap crop."
Barbara Pleasant on Saturday 13 April 2019
"Should I remove and destroy the infected squash plant or leave it in the garden?"
Teresa Schroo on Sunday 19 July 2020
"Teresa, it's your call, but I don't like looking and dying plants in my garden when I could be growing something new."
Barbara Pleasant on Sunday 19 July 2020
"perhaps I have a different pest, but for several years now, any squash, (yellow, butternut or spaghetti squash) that I grow get the fruit vigorously attacked by something that bores a 1/8 inch hole into the fruit, which results in a rapidly growing grub-like creature eating the fruit from the inside. Is this the squash borer? In my case they seem to prefer the fruit as opposed to the vine. All descriptions I read of the squash borer indicate that they prefer to attack the vine. ?"
Junglejim on Sunday 16 August 2020
"We were so excited about growing pumpkins for the first time... both plants were attacked by the squash vine borer... we found more than 100 larvae in the soil... is the soil good for planting other winter crops.. should we cover the soil with a pesticide? thank you for your advice "
D Hollinger on Wednesday 2 September 2020
"The best method I have found for overcoming the squash bug infestation (because it always comes) is to grow my zucchini vertically. As it grows I tie it to the pole I have next to it. I cut off all the leaves below the lowest fruit. There are a lot less leaves for the bugs to hide under, and no old yellow ones. I use a mirror to check under the leaves for bugs and eggs. Also, because the plants grow up, not out, there is a lot more room to grow other crops."
Jennie on Thursday 4 August 2022
"I have a new tip to add that has worked for me in the last few years. In mid fall, after the first frost, place a small pumpkin where squash grew that year. On warm days squash bugs will come out and gather on the pumpkin, where you can collect them in soapy water. I have had excellent luck reducing squash bug populations with this fall trapping method. Good luck!"
Barbara Pleasant on Monday 6 March 2023
"I grew butternuts this year and squash bugs got them, so what is written s untrue, in fact they usually leave my acorn alone, but this year they didnt"
alison on Sunday 30 July 2023

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