the product is called GreenCure. The message posted without corrections. I need help. Any sugguestions as to products and methods would be appreciated.
Mel

The most effective fungicides for blackspot are generally considered to be tebuconazole (Bayer Disease Control) and propiconazole (Bonide Infuse). No organic fungicide is likely to stop blackspot once it gets rolling in the eastern US. I use sulfur and never miss a week, but still have to select more resistant varieties or I get defoliation. I suspect sulfur is more effective than the potassium bicarbonate product Green Cure.

If any of the roses are near defoliated, I would (as you suggest) immediately cut them down to 12", remove all leaves, pick up all fallen leaves you can find, and spray faithfully. This will give you nice-looking plants in three weeks and a fall flush, and 5-6 weeks of foliation to rebuild a bit of strength to survive the winter. Use the Ortho fungicide if you have it, or better, pick up the Bayer product. Your roses will be in trouble if they don't finish the year with healthy foliage.

I keep my use of synthetic chemicals to a minimum, but if you want to do that, you need to cull the herd, seek out resistant varieties, keep up with spraying, and maybe use the synthetic when conditions are particularly bad. You might try micronized sulfur as your staple organic fungicide.

I haven't seen any controlled tests of Messenger vs blackspot, but some people here think it may help.

I posted some preliminary results in the gallery of a test I am running using Messenger along with my other sprays. While it is not a cure-all, it does help a lot. Please have a look at my test pictures of Barbara Streisand, a notious blackspot magnet. As of this date, it is still relatively clean.

Here is a link that might be useful: messenger test pictures

Jury is still out on Messenger for me. It has helped some (2 applications) since I was spotty in spraying this year, but has not totally made all plants (especially the HTs) resistant.

I'll agree with Michaelg on almost everything except for the cutting down to 12". I don't even cut things down to 12" during spring pruning. I usually don't cut them down during a blackspot outbreak. You do, however, have to start on a regular spray program now. From all accounts here, your best bet would be to start on Bayer Advanced Disease Control for Roses, Flowers and Shrubs, once every 7 days, through October.

Diane is probably right about the pruning. I'm talking about a situation so bad that only a few leaves are left at the top of the canes, on an upright variety. If I let this happen, I cut these back because I can't stand looking at them, and any further growth is going to come right up at the top of bare canes. I currently have a plant that I cut back 16 days ago, and it's leafing out with numerous shoots down low, so it will look good in the fall. It's better for the strength of the plant to prune much less than that, certainly so if it is a weak young plant. But an unpruned plant of HT type habit will look bad for the rest of the year with long bare canes.

I looked this morning at the plant I had whacked, and I had pruned it to 20", not 12". Sorry for the exaggeration-- hope I didn't cause anyone to overdo. But the plant looks very good. Once again, this tactic would not do for small new roses.

When you have a bad infestion the only fungicide that will kill the bs spores is manzate, wich is zinc and manganese.Bayer's fungicide and ortho's will prevent it but not kill the spores. I usually rotate between Bayer and manzate. it works well.

Of course, there is a big debate that always rages here about whether manzate is the only fungicide that will kill BS spores. Bayer fans disagree, claiming that Bayer Garden Disease Control both prevents AND kills spores.

You will have to experiment with both and decide for yourself.

Myself, I believe Bayer Garden Disease Control does it all. I just wish I would get off my lazy duff and use it--like tomorrow morning--before things get out of control. LOL

Kate

Just wanted to say thanks to all of you who answered my post. I found them very helpful and will look into your recommendations.
Mel

Melz, sure, that's why we're here.

Kate, if you do spray soon, send a shot east, I won't get to mine until Monday and they are looking rather shabby (and I have new neighbors too, how tacky!)... ;-))

There are several "black spot" diseases out there. I have had a severe case of Anthracnose this year (the black spot with the gray center) and from the info I've read about Mancozeb (Manzate)it will not only help this but also a case of the real B.S. as well. Does the Bayer product cover all the "black spot" bases, or would Mancozeb be a better "catch all" fungicide to use?

Maryl,

There are several "other spot" diseases that are hard to tell apart. Bayer and Banner are supposed to control cercospora spot but apparently not spot anthracnose. Then there is alternaria which likes hot weather and might be what you have. Mancozeb and Daconil should be effective against all of them.

Thanks Michael. I think this is Anthracnose because of the center of the spot falling out, but I really don't know what Alternaria looks like. This isn't a new infestation really, but one that took place during the unusually cool wet weather we had in July. Unlike B.S. the leaves seem to take longer to turn yellow(if indeed they do at all). Maybe Anthracnose is more self limiting then B.S. But anyway, this is something new (never a boring moment in the rose garden) for me, and as with B.S. only certain roses seem to be affected by it. Anyway, as always, you are a wealth of information, and I appreciate your input.

Yes, shot holes, cool spell, and despite using Banner/Bayer-- sounds like anthracnose. It was Mike_Rivers who suggested "despite using Banner/Bayer" as a diagnostic for anthracnose. Most people don't need to worry about it in the summer months, though.