Backyardfarming I wouldn't worry about the pumpkin blossoms. They fall off and disintegrate if they aren't female and pollinated. See below. As for what's eating your green tomatoes, it could certainly be any critter that likes them. Look for footprints or other signs to identify it, animal poop, or torn stems or fruits. Can you cover your plants with a filmy fabric that lets light through? Or something lightweight just at night since that's when the mischief happens. Yes, overwatering tomatoes will cause yellow leaves. Remove them to prevent disease. To tell when your tomato plants need water, stick your finger into the soil near the plant up to the 2nd knuckle. If it's dry, then deep water them, but otherwise don't. Some people even wait until their plants droop a little before watering them. Here is a link that might be useful: Pumpkin pollination

Instead of massive surgery, one thing I have done is this: ( Think of it a cleaning out clogged plumbing) Get a good spray bottle that you can adjust to have a good strong fine stream. Fill it with water (I sometimes use soapy water, or other times BT solution, but regular water will work good too) Then spray up the hole with frass coming out.. spray it really well, trying to fill up the infected cavity with water as much as you can, and in the process, cleaning up the affected area. Often the SVB caterpillar will try to come out, since its being drowned. Then I get a thin electrical wire (one that is soft, and has many copper filaments that are sharp, and I remove a little of the insulation to expose the sharp metal). Then I use the wire and probe inside the affected stem with it, both above and below the hole. Often it will impale the grub, and in a sense, I am snaking out the grub with it, like a plumber would do. I do that and keep washing out the cavity with the spray water, until I am fairly confident I got them all. (sometimes its several per hole). That works pretty good without doing much additional damage to the stem. I should make a Youtube video some day :)

That's just mechanical damage - you can see the torn leaves on the right hand side of the photo. You will often get a similar effect from insect damage - after the critters nibble on the foliage, the edges turn brown and dry - it is the plant sealing off its exposed tissue. The leaf on the left with the brown edge is also evidencing some mechanical damage - folding, bruising, etc. It just doesn't have the torn edge.

Willows - Salix species - are prone to a host of fungal and insect issues but few that bother foliage enough to be a concern. Too often folks freak out about leaf spotting or minor insect issues and rush to spray something........usually unnecessarily. Plants get problems and blemishes - pretty much a fact of life and the natural course of events. At this time of year, as ken notes, there is nothing you need or should do other than clean up fallen leaves and discard.