My healthy little shrub roses are suddenly covered in brown in less than 24 hours. What could be causing this? It is not black spot - this is much more random and came on all at once. It has rained fairly hard on and off for the last 2 days - right after I sprayed them down with Daconil the night of the Fourth of July.Could it be that the spray has burned the leaves? It did leave a white residue where the moisture gathered, but I read this was typical. Or could it have been that the spray was followed by rain?Please help. I haven't had these plants for very long, but I really love seeing them everyday, and I don't want them to die.