We're having an epidemic here in Rochester. Almost every Sycamore i've seen has the blight. We've had very cool, rainy weather which is fueling the disease. At this point most trees have lost half their leaves. Is it to late to spray them with a copper sulfate solution? Or should we waitfor the tree to put off another set of leaves and then spray to prevent a secondary infection? And should we fertilize the tree now to give them the extra kick they might need to recuperate and leaf out again? I've looked into macro-infusion there's an add on the back of the June TCI. But they're asking $300/gal for the fungicide. At that rate we'd have to charge $10-$15/inch in diameter. I'm afraid if i gave those kind of prices people would never call me again for any other tree service thinking all my prices are outrageous. Thank you for any information or advice.

Reply to post by Bill Newman, on June 11, 2000 at 20:33:12:

My recommendation on sycamores is to NOT spray now, since we are mostly past the early infection period. Weather is warming, and less inoculum is present.

The sprays need to go on early in the season. Benlate was the preferred product, now Cleary's 3336 and others do the job. The injection treatments (macrofusion) do work, but the results are not immediate. Efficacy seems to depend on the severity of branch cankering on the tree. More cankers means poorer distribution as well as more sites that may survive the treatment. I usually suggest treatments at least two years in a row, in early fall.

The cost of the material seems high (Arbotect 20S), but at $15 per inch, that is not really out of line. Consider the cost to apply three spray treatments to a 24-inch sycamore in a year, vs. one injection per year. Show them the sticker price! [g]

Any cultural treatments that help the tree are good. Fertilization, Roots, mycorrhizae inoculants, watering/mulching, etc. Don't expect any immediate change in the trees, but if you start now, they should be in better shape next year.

Finally, keep in mind that this disease is mostly an aesthetic problem. Sycamores have had it for a long time, and very few die from it. They are survivors.

Reply to post by Russ Carlson, on June 11, 2000 at 20:33:12:

(This is weird, contributing electronically from Rochester NY about a problem in Rochester NY!)
Bill --
I just want to make sure you know that Cornell publishes every year the "Cornell Recommends: 1999 Pest Management Recommendations for Trees and Shrubs" which is the source of the best research-based information for the state. Also, there is the bi-weekly publication for professionals called "Branching Out" put out by the plant pathologist Prof. George Hudler at Cornell University, which monitors pests on ornamental trees and shrubs and gives treatments that are effective and recommended. If this is news to you, you can see either of these at your local Cooperative Extension office where--in this case--the horiculture agent is a pathologist.
If on the other hand you already know about this: sorry!