Rust-colored spots on grape leaves - Ask Extension
My brother is growing a Razzmatazz grape vine in a 15-gal container outside. This is the first year he's had the root stock and it has started setting...
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Rust-colored spots on grape leaves #351555
Asked August 09, 2016, 12:06 PM EDT
My brother is growing a Razzmatazz grape vine in a 15-gal container outside. This is the first year he's had the root stock and it has started setting grapes. Since potting it, the plant has not been treated with any pesticides though has been fertilized the Miracle Grow once. In the last few weeks, rust-colored spots have started appearing on the mature leaves. (See attached picture)
Any idea what is causing the spots and how the plant should be treated?
Ramsey County Minnesota
Expert Response
Hi,
It may be anthracnose or black rot, both of which are described here: http://www.extension.umn.edu/garden/diagnose/plant/fruit/grape/leavesspots.html
You will be able to see additional symptoms which may help diagnose exactly what is going on. The fruit may not be affected, but if it is, that will also help us diagnose the problem.