Tips to help prevent Blackspot on your roses.
Avoid working in the garden during wet periods.
Prune out infected canes. Remove and destroy leaves and debris immediately.
Water at ground level (prevent splashing) and do not water the leaves.
Provide good air circulation, so leaves dry faster.
Prune canes from the middle of the plant to improve air circulation.
Prune off all crisscrossing canes to improve air circulation.
Remember, all fungicide applications are better as a preventative than as a curative.
At the end of the season, remove and destroy all infected leaves and canes.