garden q&a: Grape vines need to be pruned
Q. I have a question about grape vines. For the second year now my grape leaves have developed some sort of disease. By mid summer the leaves develop brown spots which eventually cover the entire leaf. Then it dries up and falls off. I have sprayed with a copper solution as well as with oil-based solutions. I have also removed all the diseased leaves which then generates new healthy growth. Nothing has worked. I have planted new vines across the yard, and this year I saw some brown spots on these plants as well. Is this a common ailment or is there a possible deficiency in the soil? You expertise would be greatly appreciated.
A. There are many common foliar diseases of grapes, and I suspect that your plants have one or more of them. The only way to be sure exactly which disease your plants are battling is to send a tissue sample in to the folks at the Penn State Extension Service. You can contact them at 412-473-2540 to find out how to take and send a tissue sample.
But, regardless of exactly which disease is to blame for the defoliation of your grapes, there are several things you can do to stave off an onslaught during next year's growing season. First off, be sure your plants are properly pruned. In March, remove existing vines all the way back to their second growth node and dispose of them properly. Do not let them lie in the vineyard as they can serve as vectors to the disease organisms.
Secondly, be on the lookout very early in the season for signs of fungal issues. Wet spring weather promotes these issues, and when these conditions are present, there's a good chance that fungal diseases will become problematic. Getting on a regular organic spay program early in the season is key to keeping fungal issues at bay. Though copper products are often recommended for this, I prefer using a biological fungicide based on Bacillus subtilis. One common brand is Serenade. It is available as a wetable powder and as a liquid and it works to kill a large number of common fungal organisms on fruits, vegetables and vine crops. The rate and frequency of application depends on the targeted fungal organism, but all are listed on the product's label.
A few items to keep in mind:
• Properly spaced plants are less prone to these issues as good air circulation allows the foliage to dry more quickly. Keep that in mind when siting any new plants.
• Some grape varieties are more prone to certain diseases than others. Be sure to plant resistant varieties whenever possible. The extension service can provide a list of suggested varieties.
• A summer pruning, timed when the fruits are about a quarter-inch across, also increases air circulation. To do this, remove any vines covering the developing fruit clusters, as well as those shooting up and away from the plant.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.
Send your gardening or landscaping questions to email@example.com or The Good Earth, 503 Martindale St., 3rd Floor, D.L. Clark Building, Pittsburgh, PA 15212.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Pirates acquire pitcher Blanton from Royals for cash
- Peduto blasts Wolf’s plan to borrow $3B to shore up pensions
- Work release inmate walks away from Armstrong County Jail
- Starkey: Garoppolo baffles Steelers
- Tight ends’ role in Steelers passing game continues to lessen but players remain selfless
- Steelers’ Bell unsure why NFL reduced his suspension
- 1 person reportedly stabbed at Fayette housing complex
- Steelers notebook: LB Dupree sits out backs-on–backers drill
- Extremes in weather hurt crops in Westmoreland
- Hempfield man serving life without parole for killing wife tells judge he’ll pay restitution when he’s released
- McCutchen, Pirates cruise to interleague victory over Twins