There are no grapes on the vines so I don't have any berry dammage but I...

Asked September 25, 2014, 3:21 PM EDT

There are no grapes on the vines so I don't have any berry dammage but I can't tell if this is black spot or leaf rust or what. If it is leaf rust do I have to spray the vines before they go dormant for the season to prevent damage in the spring to buds?

Minnesota

1 Response

Hi,

I am not sure if you meant to attach a picture, but it did not come through. A picture would really help identify the problem.

Black rot (Guignardia bidwellii f. muscadinii) causes a circular brown leaf spot and tends to hit young fast growing leaves. Occasionally, lesions occur on the young stems and tendrils. To treat this you will want to spray with a fungicide like copper in the spring when the shoots are 2-4" tall.

http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/fruit-spots/black-rot-of-grapes.aspx

This is information about how to identify grape rust mites and how to control them:
http://www.extension.org/pages/33107/grape-rust-mite#.VCRtfBatap4

General information about grape diseases:
http://extension.psu.edu/pests/ipm/agriculture/fruits/grapes