Most often recommended here, and what I use, is Bayer Disease Control for Roses, Shrubs, and Flowers, containing only tebuconazole. Don't buy the combo products (which unfortunately are more widely distributed). Also good is any product containing propiconazole. These are effective against severe BS pressure when used only every two weeks, and they don't burn foliage.

I'm entering my second year of growing roses. I've had black spot and powdery mildew, aphids, fire ants, (that's another ongoing saga) but nothing that my plants and I couldn't suffer through. I'd rather not spray, but I expect there will come a day.

If you enter tebuconazole into this forums' search function. you find plenty of reading about using tebuconazole.

http://www.gardenweb.com/gardenweb/query/tebuconazole/topic=roses

You did not list where you live. If you live in the State of New York, it is already banned there.

http://pmep.cce.cornell.edu/profiles/fung-nemat/tcmtb-ziram/tebuconazole/tebucon_den_0305.html

I use the Bayer Disease Control for Rose, Shrubs and Flowers. It works. I have about 100 bush's and it takes less then an hour every two weeks to keep my bush's clean. I live in a very humid area and have seen even the Knock Out roses get black spot. But this is the area I choose to live and roses are the shrubs I choose to grow. So, I will do whatever I need to do to keep them looking great. If you live in New York, you might want to check out the web site, Rosemania. They carry a wide selection of fungicides.

Bonide Mancozeb works well for black spot.

As I mention every year (it seems), how often you will have to spray with Bayer Garden Disease Control for Roses, Flowers and Shrubs depends on how severe the BS pressures are in your area. I have found in my Zone 6 garden--which is much too hot in July and August for BS to thrive--that I can get by with spraying 2-3 times in the spring and maybe twice in the autumn--no spray at all in the middle of the summer. That limited spray schedule is dependent on mid-summer temps getting up in the high 90s and 100s--BS can't easily grow in that kind of heat.

Kate

Kate is correct. Also BS can't easily spread if there is no rain at all or only a daytime shower that dries completely within several hours. However, here we have moderate temperatures all summer and usually, frequent periods of prolonged wetting. Here, BS is relentless.

The conazole fungicides like Bayer Disease Control are able to kill the fungus inside the leaf. Therefore, if you scout twice a week, you can wait until small spots appear before spraying. The leaf can be saved if you spray within 10 days of germination or within a few days of spots becoming visible.

So spraying every two weeks is routine in the worst areas, but elsewhere, you can get good control with less spraying than that.

The conazole fungicides are not widely distributed but are available online.

Good luck, warpig.

I heard that in order for BS to form, the leaves have to be wet for 8 hours or so. We've had almost constant rain (sorry Cali folks, I wish I could send it to you) so the conditions are ripe for BS. I also scale back spraying in the hotter, drier months.