A friend of mine from high school just reached out to me on my personal FB account and asked for some advice on controlling squash bugs because he had seen some of my posts related to my vegetable garden. I wrote him a response back, but then thought some of you may have the same questions. So, I am reposting the letter I sent to him in hopes that you may benefit.
Yeah I garden. Like a fool! It is kinda part of my job and part hobby. My kids accuse me of being one of those people who when asked what time it is, teach people how to build a watch. So, forgive me if I get long-winded.
First, I am not sure what stage your squash bugs are, if they are still in the nymph stage or are full blown adults. If they are full grown adults, control with chemicals is difficult, if not impossible.
Either way it is going to be work AND tedious.
Controlling nymphs and eggs. Get a bucket of soapy water. 2-3 drops of any household dish soap in a gallon bucket is sufficient. Walk around to the plants and look under the leaves (particularly those with damage) and look for eggs/nymphs. Squash the eggs with your hands; knock the nymphs into the bucket of water, they will die quickly. This process is made a bit more difficult because the nymphs will tend to scatter quickly when threatened. At this stage, the bugs are easiest to control.
Controlling adults – Sevin (I use liquid Sevin, but usually only once a year when insects are at their peak, and it is my ‘nuclear option’ so I can control things as organically as possible.) will control some of them but it will also kill bees, lady bugs, and other beneficial. For this reason spray only when the flowers are closed (early morning, late evening) to limit impact on pollinators.
The best control methods are:
- Keep as much plant debris cleaned up, remove dead leaves from the plant and make the environment as inhospitable as possible for them.
- Lay a shingle or piece of wood next to each plant in the evening. As night falls, the squash bugs will congregate under the object as a hiding/nesting spot. Then in the morning you can go and turn the wood/shingle over and easily collect the adults and either squash them by hand (they will stink similar to stink bugs) or knock them into a bucket of soapy water.
- Keep the plants well watered and well fertilized (this time of year use a low-to moderate N fertilizer with higher levels of P & K; Monty’s 2-15-15 or Monty’s 4-15-12 are excellent and easy options). This will accomplish several things:
- Insects are opportunists. If you have ever watch an animal show on the discovery network, you know that the lion will cut the weak or the lame out from the herd because they are easier to bring catch and bring down. Same thing. Insects will attack your weakest plants first. I don’t know how they know this, but they do. (This is also a chance to learn from the bugs, they are telling you stuff about your garden. So keeping them well fed, and well watered will keep them strong and make them less vulnerable.
- High Brix levels, the measurement of the amount of sugars in a plants also seem to deter insects. Don’t know why, just know in side by side studies that I have done, those plants with higher brix have less insect damage.
- Squash plants grow very quickly and can easily grow past any damage done by a squash bug. Making sure they are healthy, well fertilized and well watered will help this.
My favorite control method is to do nothing. That’s right. I said do nothing. Here’s why. Once the plants are up and growing normally (controlling the bugs in the early stages of plant growth is imperative), there is not much the bugs can do to stop them. The bugs tend to feed on the leaves, not the fruit – especially until the end of the season when the leaves are starting to wilt naturally. By then I have enough squash put up to get me through the winter anyway, so any fruit I harvest after that is just gravy. Squash plants grow so rapidly that the impact of any one or even several bugs is going to be minimal and is easy for the plants to keep up with. Squash bugs have sucking/piercing mouth parts. Because fo this, they do not eat away your leaves like caterpillars or beetles do. These wounds will kill the leaves in the immediate area, so they will look spotty, but unless your plants are very small or your infestation is extremely large they just can’t do enough damage to prvent the flow of enough nutrients to impede plant/fruit development. Basically, the work required for complete control, for the benefits, attained just isn’t worth it to me.
So to summarize, your options are:
- Scout and control manually with a bucket of soapy water.
- Lay out a shingle or piece of wood each evening, collect and destroy the adults in the morning.
- Use sevin or other labeled control as a nuclear option, use it in the evening or early morning once the flowers have closed to limit the impact on beneficial insects and pollinators like honeybees.
- Keep them well-fed (fertilized), watered, and generally healthy.
- Do nothing once your plants are matured. They won’t eat much, really
BTW…I don’t know if you do this or not…but I have found out this season that the male flowers from the squash plant are delicious! Harvest one or two this evening and enjoy a squash blossom quesadilla or dip them in a relleno batter and fry them. (You can also stuff them like a stuff bell pepper, roll them and either bake them, or dip them in batter and fry them.
Happy growing, and enjoy the NM sunshine, I know your squash are!