I would agree with not using any systemics on any edible fruits/plants (Many of them are now being tied to honeybee colony collapse too. The bees IMO are just the canary in the coal mine). For most trees you need nothing to seal a pruning wound, the tree will take care of it. This assumes that healthy wood was removed, and done properly so that the growth area at the base of the limb was left intact. Look online for some diagrams of how to do this. If you must use something, the old black oil based tree wound compounds are still available. As for borers, there are quite a few options for killing them once they are in a tree, from running a wire up their hole, to injecting predatory nematodes or insecticides in the hole. General prevention is harder. One source claims that white interior latex mixed with spackle (sheet rock joint compound) to s spreadable mix, painted on the base of the tree works. Others claim fine gravel at the base of the tree will deter borers. And their are traps for the adult borers too.

I've painted trees w/ full strength latex and not noticed any problems. I have seen fissures in the paint, but I've not noticed any problems from it. I quit painting trees several years ago. We don't get cold or snowy enough winters to experience SW injury. I do get some sun scald on the tops of scaffolds if I open the trees up to much during the hot summer. I've found vigor will heal anything but the most severe bark injury in my area. We had a terrible hail storm this spring which chewed up the bark badly. Most of the trees already have the wounds closed up. Re:DDT I can live without it, but it really wasn't responsible for decimating the American Eagle. Eagle population was dangerously low before widespread use of DDT. Eagles and other large predatory birds were considered pests in the early 1900s. Farmers/ranchers would shoot them on sight. DDT did destroy their eggs, but people hunting them was their biggest blight.

This is an off-label use for those fly-strip bars that contain dichlorvos, so do not expect that competent orchards who have to follow federal rules will be using this method, but it does work for the small orchardist. I had a borer making frass on one of my trees. Tried to get him with a wire and all that. I thought I got him, but the next day there was more frass. So I cut a sliver of plastic off one of the fly-strip bars that I store in the freezer (in a jar, so that it is preserved indefinitely) and poked that into the borer hole. Then the opening of the borer hole was plugged with kids modeling clay (to confine the dichlorvos vapors to his tunnel). The vapors from the fly strip sliver killed the borer dead as a doornail. No further damage to the tree, and it chugs on.

"If I don't find any nicks or whatnot on the jar lid, why would I need to change the jar? And I thought I would definitely want to add a new lid- I don't know how I would tell if it were necessary." The new jar recommendation is based on the assumption that you may not be able to see or feels very small nicks in the rim. It's your choice to replace it or give it a second try. If it doesn't seal on the second try just put it in the fridge. Lid evaluation is based on the condition of the rubber seal band. If deeply indented, replace it. If any edge appears warped or dented, replace it. Again its basically your choice - your eyeballs. ;-) The goal is to not end up with unsealed jars after 2 processings. Also make sure you aren't screwing the rings on too tight as that often causes seal failures. And don't overfill the jars as jams tend to boil over and create weak seals so increase your headspace a smidge if necessary. And don't mess with the jars lids or bands once out of the canner either. Some just take longer to seal than others and it is easy to break an early seal. No you don't have to reheat the jam assuming an approved recipe in the first place. Dave PS: and feel free to vent ;-)