It's not how many canes you leave that's most important, but rather how many clusters of fruit. The more foliage you leave the more fruit it can support. So leave as many canes as seems appropriate. But thin off some of the clusters if there are more than about 10. I first thin off the smaller of the two clusters that are often on each cane. Then thin more off if that seems appropriate.

I'm new to this forum, and I do want to thank Myardor, fruitnut, harleysilo, and others here for the info, pics, and suggestions. One reason I come to forums like this instead of trying Google first is that Google usually gives me tons of extraneous information and links to sites that aren't all that relevant and/or are mainly commercial advertising sites. Usually, if I can ask a question of someone who's knowledgeable in a field, it's a lot more efficient than just searching through the library's card catalogue or wading through all the stuff that Google yields. However, if I ask a question in a forum, I don't expect people to go out and do my library or google research FOR me if they don't already have the info. :) I just see forums as places for people to share info and opinions and experiences they already have - or to direct each other to good info sources. Speaking of "pruning," :O back in May I had a guy doing some yard work for me and he was totally incapable of following instructions or directions. Long story short, after we had carefully moved all the long offshoots from my 22-year-old purple Concord grapevine onto the trellis I wanted to train them to, he proceeded to take a chain saw to the 5-inch diameter main trunk of the vine, right near the ground! (No, I didn't kill him, but I wanted to!) The stump hemorrhaged sap for at least 2 to 3 weeks. I tried grafting some shoots from another (Champagne) grape onto the stump, but I don't think that "took" because it was too late in the season. Anway, new growth has been sprouting from the old stump ever since late June, and the leaves look very healthy. Does anyone how long I'm likely to have to wait for a decent crop of grapes from this severely "pruned" old grapevine?

Nice vine. You can have a upper level & a second/lower level. You make a "T" about 48-60inches high for the top, then a lower "t" for the bottom about 24-36 inches high. You do not have to have the lower vine. You should mulch under the vine for the complete run of the vine to keep weeds down & out of your way. They are two ways to prune, so study both & do the one that you think is best. Check out the fruit forum too.

Grape leaves are a favorite food of several insects, not the least among them Japamese Beetles. Unless wholesale defoliation is going on, you might be wasting time and money to spray, especially at this time of year. So far as the variety, if you have grapes left at this point without spraying, they could very well be Concords. These require about the least amount of care here in the East. Concerning the pruning, that would take more time than I have. Contact your county extension agent (listed under USDA, Cooperative and Extension Service in the phone book). They might even be able to visit your place if it is on their route to somewhere. Often times they are too busy to visit a person with a few trees and a couple of grapes, but if you aren't in a hurry, they may be out. Since grapes are best pruned in the late winter, you have planty of time.