|I have hybrid tea roses and floribunda roses. All of my rose bushes have some kind of orange "fungus" on the unside of the leaves. In addition, I noticed some small black dots
on the unsides of the leaves as well. What is this and how can Icorrect it?
|Sounds suspiciously like rust on your roses, and the beginning of black spot. Both are quite common foliar diseases. Begin to control by cleaning up any debris under your plants, and keeping fallen leaves and blooms picked up all year. Prune your roses and remove all the prunings from the garden. You'll not only cut out any diseased plant parts, but you'll also open the plants up to better air circulation, which will help your plants avoid these diseases later in the season. Make sure your roses are in full sunshine (8-10 hours each day). To avoid the spread of disease development, monitor your plants and pinch or prune off any leaves that develop spots.
There is a new product available called Soap Shield Fungicidal Soap (available fromGardens Alive, 5100 Schenley Pl., Lawrenceburg, IN 47025, ph# 812-537-8650) that is described as an environmentally-friendly copper-based fungicide effective against black spot and rust on roses. It might be worth a try.