Last year, I fought squash bugs over and over until they won. Technically, they did not win, but the plant viruses they carry caused my plants to collapse. I still got squash, but not a good production. This year, I was determined to win the war on squash bugs. I did not use Sevin Dust a single time. I stayed with the liquid Sevin. My first treatment was on the ground around the plant using Bayer Advanced fruit and vegetable treatment that goes on the ground around the plants and is systemic. In addition, I checked the plants for bugs every few days (sometimes daily) and gave them the thumb and forefinger 'hug-a-bug' treatment. I also sprayed with Sevin weekly and after any rain shower that washed it away. I also examined every leaf of the small plants for squash bug eggs, giving them the aforementioned hug-a-bug squish treatment. I briefly tried Spinosad, but found it had little effect on the bugs. As my plants matured and started producing fruit. My insecticide changed to Malathion spray. I broadcast sprayed the leaves and then sprayed the stalks from the ground out to where the bloom pods began. I tried my best to carefully keep insecticide off of the bloom pods so I was not directly attacking bees. Even as the plants were mature and producing nicely, I would still find pods of seeds on the leaves. My grandson got really good at spotting them. With all this attention, we've had a tremendous squash harvest and continue to get two or three times more squash than we can eat or put in the freezer. We have not had any infestation of squash bugs. I have not even seen a single bug in the last month. I've seen grasshoppers, but no squash bugs. I noticed an assassin beetle and a big wolf spider this week, but no squash bugs. The beetle and spider are good guys, helping me by eating other bugs.
It's taken a tremendous amount of close attention and work with different insecticides to keep my squash bugs away. Weekly sprayings and lots of inspections is something I can do because I am retired and have so much spare time to spend on my garden. The payoff is buckets and buckets of beautiful yellow squash and zucchinis. I'm sure the Sevin dust works where you can get it, but I just like the liquid insecticides and my little 1-gallon sprayer for application. With the 1-gal sprayer freshly mixed, I can generally spray everything in my whole garden, including a light broadcast spray of my tomatoes to keep worms away.