Spray regimen question?

I am growing the cultivar Petite Pearl. This is there first year and I just planted them recently. I found the following information for them regarding disease tolerance.... "Petite Pearl is highly disease resistant to powdery mildew, downy mildew, black rot, and bunch rot". I am in Illinois 5B. Given their disease resistances, what might they not be resistant to and vulnerable to, in my zone and area? What kind of preventative spraying should I begin to do?

not familiar with this grape but I would suggest chatting with neighboring vineyards and solicit there views. also the local count agent might help.
there is not many other diseases left for the grapes to be vulnerable to, insect damage would be my next worry such as leaf philloxera and Japanese beetles.
try the local university agricultural department.

You shouldn't be having to spray for much with new vines. The first season main goal is to retain enough of leaves to make energy for the roots - so some insect control or fungicide as needed. I don't know much about the variety you are growing but I think what is meant by resistance is that the vine will need less fungicide spraying during the season and not none at all. Talk to others growing the vine near you to see what program they are using as salcoco says is a good place to start from.

I agree with the other two, first and second year vines need less spraying in general if you do not plan to leave fruit on them. As CTDrew said, resistance to a disease does not mean it will never get it and it is easier to prevent fungal disease that cure them. You should only need a product for PM and DM, powdery mildew and downy mildew for the first year or two and then add something for bunch rot when fruiting begins. Most guides say to add insecticides as needed but I start out with one and up the dose if needed.

Thank you gentlemen for taking the time and for the helpful answers.

One disease not listed that is important to control in early years also is phomopsis and to an extent anthracnose if in your area. Both of them affect the leaves, shoots/canes and fruit. Once it is on the vines it is difficult to get rid of. A protective mancozeb spray during early growth is very helpful.

I grow Petite Pearl, have not had any problems with mildew, but i do have to spray for black rot, if i don't sprap will lose most of the grapes. You should have no problem this year or next other than Japanese beetles, if you get grape pods pull them off, 3 rd year you can keep a few pods per vine. I spray every 10 to 12 days with Mancozeb fungicide and switch off with Captan WP fungicide. So much depends on the weather, amount of rain, more problems if it is VERY humid, also helps to thin the leaves around the fruit so you get good air flow. Hope this answers some questions. Its worth it, makes a good dry red wine

Thanks for the info everybody. I have some Mancozeb coming tomorrow. I have somewhat of an agricultural background but have never been around grapes. Without the info you all supplied I wouldn't have known where to start.

This is the arbor I've built. I only have planted eight vines.

You might have a ventilation problem if the leaves get to thick and it doesn't look like you will spray any sulphur...or only if you like yellow spots on your house. Pick your spray carefully or you will have some spots.

This was really my only option as everywhere else is too shady. Does the sulfur wash off ? Or is it permanent?

Does the Mancozeb wash off in the rain? Also after rain, does it need to be reapplied?

I always went with the amount of rain that my vines received between spraying. I figured everything washes off after 1 1/2 inches of rain. As far as Sulfur i have never used it by its self, have used lime sulfur spray eary spring, before bud break, but it is not sold anymore. They do sell sticker which is supose to make the spray last longer with rain. So much depends on the humidity and wind, high humidity and no wind to keep the vines dry means funguses, PROBLEMS.

My experience is that sulphur is it's hard to get off once it dries.

So far this year, the weather man sucks. I spray, it rains! I sprayed yesterday and it just finished pouring. I'm not sure if my powdery mildew spray was on long enough to do anything.

Supposed to be a nice day, sprayed for bugs this morning in my orchard too....

The general rule of thumb is that for every inch of rain you get, the effectiveness of the spray is halved and that after two inches, it is time to replace.

Grapeman thanks for the stats. Thanks to everybody for general responses.

I have a question about row spacing. I am looking ahead to planting three short rows of Petite Pearl next spring, at my residence. The rows will be about twelve feet long. I want to begin to prepare the soil for them starting from now through the fall. I know nothing about the different trellis systems. My question is this: I will be mowing between the rows with a lawnmower, no tractors etc. How close can the rows be? They will run North-South. Illinois 5B

You want enough room between rows to work comfortably, be that mowing, spraying, harvesting, pruning, etc. You also want to get enough light and air flow to come in. If you cram in too many vines to the point where you lose airflow and light the problems those conditions cause will eliminate any benefit to more vines. I work my vineyards completely by hand, both have around 30 vines. For hybrid grapes, I keep a 5ft strip of grass and about a foot and a half clean area on each side of the vine(3 foot planting bed), total of about 8ft between rows vine base to vine base. For vinifera, I have those rows at about 10 ft total to maximize airflow. What works on my site in my climate may not work for you, though.

Ct Thanks for the answer.