Spraying grapes 101 - Question

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Jul 12, 2013
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This is my first posting to this forum.

I've been growing cold hardy grapes in south western Quebec (Cantley) for about 8 years. I'm growing mostly Frontenac, St-Croix and Marquette varieties.

From early May until about last week, it has rained almost every day and it was a colder spring than usual. Because of this I've had to contend with more disease this year. I've never had to regularly spray my vines in the past and wondering if I should have this year. I've gotten a bit of downy mildew, anthracnose, and black rot. I usually do not have to deal with much disease but this year is exceptional. In the past I've sprayed some potassium bicarbonate to control a bit or antracnose, and black rot was very minimal.

Would appreciate suggestions on what has worked for you to control these diseases, in terms of fungicides readily available in Canada from the store shelf.

I have some Bordeaux but I'm reluctant to use it in case of phytotoxicity. Around this time of year I always get Japanese beetles munching on the leaves. So I've found something that goes by the name of 'King Fruit and Garden'. It contains Captan, and also contains Carbaryl (might help with the Japanese Beetle problem), and Malathion.

Hope you have a great season,

I deal with black rot, powdery mildew and anthracnose yearly since I am in Oklahoma. Even though the fungus may not appear to be active the wet weather can onset during wet cool, weather. I believe you are on the right track. The black rot and anthracnose and downey mildew all have life cycles and under the conditions you described can become airborne during spring after wintering. I like Captan it works as most fungicides do. It's important to control these diseases early in the season, pre-bloom and three to four weeks after bloom. Sanitation is critical. Any removal of mummies and infected canes will be beneficial to your success next season.
I would be careful using anything with Captan AND malathion. I used a spray called "rescue" and it burned several of my grapevines. It has both captan and malathion in it. I sprayed late in the day also, not midday. The vines recovered quickly and it only affected about 2-3 different varieties, but I'll never use it again.

I didn't have any problem before that, I just decided to use the combination spray. Now if I spray it will be just carbaryl for bugs, and perhaps captan if I need it for fungus.

Just remember to follow the manufacturers directions when mixing and applying fungicides. These chemicals are safe and have been tested as long as you follow the safety procedures.

I live in No. GA., the fungus capital of the world.
I started using a product called Immunox made by Spectacide. It does an excellent job stopping black rot in its tracts. The best part about it is, it’s a systemic. It does not wash off like other fungicides do. Here is a note of interest: Lowes sells a 16 oz. bottle for 12.98 and a 32 oz. bottle for 16.98. The 16 oz. bottle has a 1.5% concentration and the 32 oz. bottle has a 2% concentration. The 32 oz. bottle comes in a hose end applicator and only listed for lawns but has the exact chemical as the smaller bottle but stronger so you can use a little less. It is defiantly working for my situation.

Captan is kind of nasty. Make sure to read the label for approatie dress. Not supposed to get it on your skin or inhale it. As with any chemical make sure to follow the guidelines set by the manufacture for your safety. Carbaryl is basically seven. It will kill your beetles.
For 3 straight years my grapes were totally destroyed by black rot. I started spraying the second year and again this season. I've held it off longer this year than last but only a bunch or two are left.

Last season the leaves were burning a bit after spraying in morning. This season I slightly cut back the mix but black rot set in after over 2 weeks of everyday rain, temperatures in the 90's and humidity so high you could swim in it.

I sprayed every other week to no avail and did start early. So frustrated. Ready to rip them out.

I used a product with captan in it called Fruit Tree Spray (Lowes). It was the only product I could find that had captan 11.76%

I don't like using chemicals on our grapes but it seems either the grapes are doomed or us. Pick one.

Are there grapes that are resistant to black rot? Would love to grow them.

There are some grapes growing wild not far from here, left alone to hand no trimming just wild. Their fine. Go Figure

If its not black rot its birds. Hats off to you big time vineyards. Don't know how you do it.
Thanks everyone for all your help. I will be careful and if I try something new, I`ll first try it on a few vines to see in case of damage before proceeding to treating the rest.

I believe the captan for grapes is around 48.9%. You should rotate your fungicide or there will be a resistance built up. Make sure the concentration is correct for your sprayer and per acre. We spray every 10 to 14 days. Maybe look into a surfactant to help the spray "stick". This is what works for us you situation may be different but I thought I would throw in a few ideas

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