Key:  ++++ = excellent, +++ = good, ++ = moderate, + = slight, 0 = not effective

a.  Benomyl resistant strains of the powdery mildew fungus are so widespread that the material is no longer recommended for management of this disease.  Benomyl-resistant Botrytis strains are also common; when resistant strains are present, benomyl will be ineffective and should be used.

b.  Most insecticides labeled for use on grapes are incompatible with lime.  Check insecticide label for incompatibility with alkaline spray materials.

c.  Ridomil MZ formulations (Ridomil + mancozeb) will give slight control of Phomopsis and Black rot, due to the relatively low rate of mancozeb that is included.  Ridomil copper formulations will provide slight control of powdery mildew.

d.  Sulfur efficacy declines rapidly at temperatures below 65°F; thus, early seasons sprays may give mediocre management, especially on highly susceptible varieties.

e.  Although poorly documented, resistance to Rovral appears to be common in vineyards where this fungicide has been used regularly over a long period of time.  Because Rovral resistance "dies down" over time if the product isn't used, it is recommended that this fungicide be avoided for 1 or 2 years where it has been used regularly in the past, then applied no more than once per season if and when use resumes.

*Exerted from the 2001 New York and Pennsylvania Pest Management Recommendaions for Grapes.