Prevention is the key.
You must start in the fall – that said I am starting in June. What can I say. If you start in the fall (and I will this fall for sure) it gets things off to a much better start with lower numbers of bugs ready to spring from the soil in the spring and do what nature intended – lay eggs – or go forth and multiply!
Once the squash are done (and that may be sooner than later if you had an infestation of squash bugs) clear up all the refuse and mulch and burn it! Yes burn it. Get rid of those eggs that will lay waiting all winter to attack in the spring. Many sources additionally recommend hot composting but I’m not taking any chances and we will burn the refuse about a month after the squashes are all dead and done.
Then plant a cover crop for the winter so the soil is nicely covered. You don’t want to mulch the squash ever again. More on this later. Also plant cover crop where you plan on growing your next summer crop so it is ready to go.
In the spring make sure your squash plants are big and hearty if you are transplanting them out. I’m going to transplant and will start my own. No spindly plants because they are too easily knocked down by just a few bug bites. There could be a whole conversation on seed starting so we won’t go there today.
It is without a doubt recommended by many if not all reliable sources that the single most effective deterrent to squash bugs is to cover those baby plants as soon as you plant them. Most sources recommend lightweight row cover. I also read about people using mosquito netting. It should work if you are in a pinch and that’s what you have. Make sure the covering is tight to the ground and as close to the plants as possible. You will have to reposition the cover as the plants grow.
You might be asking “what about pollination?”. One of two solutions; the first is to remove the row cover and start using other measures to keep the bugs at bay. The second, and this is my favorite because we are small time gardeners, is to lift the cover occasionally and hand pollinate. It’s easy (once again that is another conversation we won’t go into).
So about those “other measures”. There are some serious “must do’s”.
The second single most effective thing you can do is hand pick squash bugs off the plants along with any eggs you can find. Leave a lidded container nearby with an inch or so of soapy water. The bugs will expire in the soapy water. Here’s my favorite part… buy a pair of wooden toaster tongs for a couple bucks and use those as bug pinchers. We bought a dozen pack and hang them in handy locations all about the garden. They last for many seasons and take the ick factor right away. Great for tomato hornworms etc.
Do NOT squash squash bugs. The scent they exude attracts more squash bugs so I understand. And squash bugs can find a patch of squash as far away as half a mile.
Boards; a small thin board placed on the ground right next to each plant will provide a place for the bugs to take cover at night and every morning early you can lift it and kill the bugs. Use the soapy water in the lidded container. This method works best when nights are cooler. Here’s a neat trick I read about. Adhere a sticky trap to that thin board. Then lay the board sticky side down on a very short riser so it is just barely above the soil. It still gives the bugs a place to hide and a lot more squash bugs will be caught. I haven’t tried this yet.
Water; water somewhat vigorously in the morning around the base of the plants and see the bugs come scampering out and climb to the top of the plant. You can then easily pick them off. Remember the soapy water… 🙂
Chemical treatments include;
diatomaceous earth – kills squash bugs but do not apply it near the flowers as it kills a lot of other bugs including a lot of beneficials. It needs to be reapplied every time it rains or there is a heavy dew. It is safe for all pets etc as long as you do not breath it in. Please use a mask if it is windy.
insecticidal soap – kills squash bugs especially well if they are young (not so much for adults) and also especially well if it also contains pyrethrum which comes from the Chrysanthemum.
sabodilla, and neem oil – once again these can be dangerous to your garden
Sevin dust is now of little use against squash bugs and not environmentally healthy.
Tape a small mirror to a hoe to easily inspect the underside of leaves which is where the eggs are most likely to be – we have two long handled mirrors that we bought a few years ago and this is a really handy tool!
CHECK YOUR PLANTS DAILY or at least every couple days and stay ahead of those squash bugs!
Praying mantis eat squash bugs but they also eat ladybugs so it’s your call. They are available commercially.
Tachinid flys also eat squash bugs – I have not seen them for sale.
Some anecdotal evidence that lizards eat squash bugs. Lizards eat a lot of insects. They also like bark mulch hence our lizard population with all the shredded wood and bark in our garden walkways.
Companion planting may have some benefit. It is reported that the flowers of alyssum, calendula, daisies, dill, fennel, and mustard greens all attract tachinid flys. Marigolds, nasturtiums (which can be somewhat invasive), radish (especially white icicle), tansy and mint are reported to be offensive to squash bugs.
A bug collection funnel/containment can be made from two gallon milk jugs. See the link below.
DO NOT MULCH SQUASH PLANTS – unless it is with fresh hot composted compost and only a light layer.
ROTATE your squash plants on as long a rotation schedule as possible and as far away as possible. Some people claim skipping a year will help but we didn’t grow squash for about five years and then had squash bugs, so who knows.
One person stated on a board that she used a dab of clear nail polish on squash bug egg clusters because it was too much effort to remove them. I see some validity there.
Prevention is the most important thing you can do. Handpicking bugs and eggs is the next priority. Resort to chemicals only if you have to (even organic ones have negative effects).
The best comprehensive article I have read lately about growing squash without squash bugs is at this link, Squash Bug Controls . It is best to use preventive measures rather than wait until there is an infestation and then have to resort to harsher methods. I hope you read this article as it is quite comprehensive and very readable. https://attra.ncat.org/attra-pub/download.php?id=138
Wikipedia, pyrethrum, https://en.wikipedia.org/wiki/Pyrethrum