Found it! Phenomenal. Exactly what I was looking for. I highly recommend this for anyone else looking.
Thank you so much!
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My advice would be to talk to your local extension service about the identification of Pierce’s Disease in your county. That is the number 1 threat to table grapes. The disease is spread by leafhopper insects. It is not as prevalent in the more northernly latitudes because the insects are cold weather adverse. There is no reasonable treatment for PD although there has been development of PD resistant vines.
In my case I was aware that I was borderline range of this disease but decided to take a gamble on it. It took something like 6-7 years for it to show up in my vines. Plenty of delicious Jupiter, Reliance, Swenson Red grapes off of something like 15 vines. Then one year I saw discoloration of leaves and soon after a “matchstick” appearance on my vines. Grapes took on looking runted and sick. Took a sample of the vine to my local extension office and they identified it as PD. The lady advised that the lab said to switch to a vine that was supposedly PD resistant called the “Saturn” vine. Well I did not do that but transitioned to muscadines. I still have a Concord vine but it is just somewhat PD resistant.
Another serious threat to table grapes are birds and raccoons. Especially the robins. I had about 150 feet of vine and I would chase a flock of something like 25 robins off of one end and they would simply fly to the other end intent on eating all of my grapes whether they were ripe or not. If I was doing the table grapes again I would build a permanent cage like structure of net wire 10 high and of proper width and length that positively kept the varmints out. Then build an inside trellis and finally plant the vines. Just my thoughts.
I hope this helps.
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Penn State didn’t list it.
Sutton_ProgressReport05.pdf (225.8 KB)
This report makes it seem like the Trenton area is relatively safe (for now) I’ll consider myself lucky!
The cage around the trellis is an interesting idea. I haven’t finalized exactly how I want to trellis yet (my plan was to just use a pole the first month at least) but I may want to incorporate some sort of bird defense
I checked your list of Thomcord, Compassion, and Somerset seedless with google for being resistant to Pierces’ disease. Of these Thomcord and Somerset Seedless were said to be resistant to PD while Compassion was not. Maybe the problem in areas like West Tennessee where the PD pressure is light is that PD may weaken the vine so that a cold snap may end up killing the vine. I suspect that is what happened to a Concord vine that I had.
None of those varieties are resistant to pierces disease. They will all die rapidly under PD pressure. However, given the location in zone 7a, it’s probably not going to be an issue. PD is rarely severe, if present at all, under those conditions. It is limited by winter lows. It doesn’t like the cold.
Grape varieties being resistant to PD is not the same as varieties being immune to PD. There are levels of resistance. That resistance is high on some varieties and low on others. Some in between.
My experience with PD was that the severity of the disease was not consistent across several vines of the same variety. One vine could have severe symptoms while other vines of the same variety could be much less affected. At the time I considered the switch as being either “ON” or “OFF” with no in between. It meant that I got rid of all of the vines of that variety.
That extends to the map that zone7a posted earlier. If that map shows even light susceptibility to PD I can not recommend planting susceptible varieties in that area.