I would not bother with nematodes for cuke beetles. They come in with the air currents as the season warms up. Killing the overwintering ones is nice, but it's a drop in the ocean.

I am in Wisconsin where very few overwinter sucessfully. We do have corn rootworm beetles that are often confused with cuke beetles, but the actual cuke beetles die in the winter here. Even so, this is the first year since I can remember where I had almost zero issue with them. I have had years where I would shake a plant and they would take flight in numbers great enough I almost cried.

This is just from what migrates in annually.

In the bad years there really isn't much you can do other than hope they don't damage plants too much or use a broad spectrum pesticide. They are a really, really challenging pest as they have few predators caring to eat them.

Think of it this way. The entire state I live in has almost none that survive the winter. It's like the entire state used nematodes on every inch of ground. And it's still common for them to arrive in hoards.