SPRAY DAMAGE OR DOWNY MILDEW?
The rose gardener who confuses the affects of Downy Mildew and spray damage is not alone; there are many of us who make the same mistake. I recall a Colonial District meeting in Williamsburg, Virginia, to which a rosarian from this area brought several infected rose stems to find an answer to what was causing the discoloration and dark brown irregular spots and blotches on the stems. Those in attendance, who ventured an opinion, believed the problem to be spray damage or “pesticide toxicity,” but a few people contended that the damage was the result of Downy Mildew. In my opinion, aided by some investigation on my return to Timonium, we were looking at the ravages of Downy Mildew. Even plant pathologists acknowledge it is easy to confuse the two. An excellent article appeared in the ARS, August, 1991 issue of The American Rose Magazine by John Mattia from Connecticut on Downy Mildew describing how he and other rosarians confused its devastation with that caused by “spray burn.” His sol
