[From Rosa: The Journal of the Societe des roses du Quebec Rose Society, June 1999, p.6:] Many varieties claim to be disease resistant. This does not mean that they are immune. We amateurs do many things that render our rose bushes susceptible to all sorts of problems.
- Roses are planted too close together
- Dead leaves and other garden refuse is allowed to accumulate in rose beds
- Improper pruning does not open the centre of rose bushes to allow good air circulation
- Continual use of the same fungicide allows disease to develop immunity to it
- We await the first signs of disease before starting a spraying program.