That might not be Black Spot. It could be something called Downy Mildew. It causes very quick leaf drop--sometimes of entire gardens. It requires high humidity and temperatures that hover around 68 degrees for long periods of time. It doesn't cross leaf veins like BS.

http://www.rose.org/rose-care-articles/downy-mildew/

Try Serenade. Bayer makes it. It is an organic spray made from good bacteria that does in both black spot and powdery mildew. It must be sprayed weekly, on both leaf sides, and is washed off after a rain, and needs reapplication. If it rains the day before each scheduled spray, you're living a charmed life, Serenade wise.

I have not used it myself, because as many posters here at the Roses Forum can attest, I have not crossed over from the dark side yet. I still use big, bad, corporation made CHEMICALS! They think I worship at the altar of Bayer, and tithe to Ortho.

I cannot say Serenade works as it is claimed to or not, but it is worth trying.

My niece, an organic food proponent, new to roses, was supposed to spray with Serenade this season. I got her all the stuff needed early on. She slacked up, as youth is prone to, thinking rose diseases will not hit her 40+ roses.They're immune, you know. Well, she paid dearly with essentially a backward, unsuccessful year.

One alternative for you is to grow fungus/disease resistant roses. Other than the Knockout series of shrub roses, Kordes roses, a German company, is coming out with outstandingly disease resistant roses. They have a more diverse selection, compared to Knockout shrub types, like: hybrid teas, climbers, and floribundas. Look for the designation ADR on Kordes roses. That signifies that roses so awarded the ADR title, have passed rigorous disease tests in no spray test plots.

Here are some ADR, Kordes roses to consider:

First Crush, Zaide, Summer Romance, Madame Anisette, Earth Angel, Cream Veranda, Dark Desire, Lion's Fairy Tale, Pink Enchantment.....

Moses

Downy Mildew is a systemic disease that typically isn't controlled by either Bayer Advanced or Immunox.

Bayer Aliette Fungicides | Crop Science US

https://www.cropscience.bayer.us/products/fungicides/aliette

Aliette® fungicide delivers true, two-way systemic protection against Phytophthora, downy mildew, and other diseases. With multiple modes of action, Aliette ..

Typically starts at the top and works its way down the plant.

I found a very old bottle of rosepride that had been lost way before I moved. I don't think they use this formula anymore. After my love song and twilight zone defoliated twice, I used it, and it has worked. I bought the bayer rose and flower disease control to use when this runs out or doesn't work. This bottle is probably about 5 years old, I was surprised it worked, but it did. I can add one to the bs free list. Rose of hope. Healthiest rose I've ever planted. Even Belinda's dream got a touch of bs with all the rain this summer, but Rose of hope didn't get anything. I don't think it gets very big, but the blooms are beautiful, and it's super healthy.

I was initially confused after reading through the above posts, thinking this was a "ships in the night" situation. But then I realized it's probably just a matter of "cross posts".

See the following thread concerning late season black spot:

http://forums2.gardenweb.com/discussions/4863692/tons-of-late-season-blackspot-should-i-worry-for-next-year?n=12

Zack,

Help us out please. The lowest price and size I found for Aliette on the web is a 5 lb. bottle at $164.99, pp. from Do My Own Pest Control, and at $163.99 from Rosemania. Where could one get a smaller amount, and at what price?

Is Aliette an organic fungicide?

Aren't you the fellow who recommended Immunox to me when I had persistent powdery mildew this past spring? Doesn't it work any more for PM?

Moses

The Outrider,

Temps do effect how fungi start, but once established they seem to go into overdrive, regardless of temps. Black spot has a narrow window of opportunity temp wise, but it amazes us how extremely opportunistic it is, and how quickly it strikes. Once established on susceptible roses, expect defoliation, sometimes completely.

It is the same with powdery mildew...dry weather, hot days, cool nights, and it rears up its hoary head!

Moses

Henry beat me to it, it is late in the season, and all kinds of issues start showing up in our area this time of year. I would really need photos to determine if it is downy mildew or black spot, as the markings can mimic each other this time of year.

Downy Mildew and Powdery Mildew are two very different diseases. Most people rarely see Downy because it requires very specific weather conditions that aren't likely to occur outside a greenhouse. I've only seen it rarely in my garden, but do know that it is more common in other gardens. Downy Mildew is related to the disease involved in the Irish potato famine.

The Origin of Plant Pathology and The Potato Famine

We are starting to have end of season yucks here too on some roses TheOutrider...Happens at the end of every growing season...The sun has changed positions, less daylight, soil and outside temps get cooler, etc. etc.

Yes please post pics TheOutrider....Just in case it is DM...

Zack, I have a Lamarque that took a sudden bad turn during wet weather in Fall of 2015. I think it probably had Downy Mildew. Yada Yada Yada, it has not died but has not really recovered. I think I might best remove it. I got another "Atmore Lamarque" from rosepetals that I put in a different location and it is doing great at present. Do I have to worry about planting something else where my DM stricken plant is? The plant is not currently afflicted like it was, but just sitting there pathetically, not normal pre illness. I figure to put something different in that spot if it is safe to do so.

There are multiple organic fungicides that will help to control various rose diseases. None are 100% effective but if used in conjunction with good cultural practices, they should keep black spot and powdery mildew down to a very manageable level.

In addition to the Serenade (Bacillus subtilis), neem oil, sulfur spray and the home remedies of baking soda or milk mixed with water and a few drops of vegetable oil are all natural or organic and moderately effective. btw, both the milk and the baking soda solutions alter the pH on the leaf surface, making it inhospitable to fungal spores.

This paper suggests that removing a severely infected plant may be the only realistic management option.
https://www.extension.purdue.edu/extmedia/bp/bp-68-w.pdf

I have heard about treating Downy with a systemic soil drench of Aliette, but this obviously isn't cost effective for one plant if you have already have that variety. Makes more sense to propagate another one, if that variety is no longer under patent.

Hi Moses,

You can get Aliette in smaller quantity internationally on Ebay, as in the example here for $35:

http://www.ebay.com/itm/KB-Aliette-600-Gr-150-Fungicida-Sistemica-La-Base-De-Fosetul-Aluminio-/112270262415?hash=item1a23d4408f:g:TJgAAOSwjDZYe7hH

They do ship to US, and I bet it'd still be significantly cheaper. With the money saved, you could get some of that nifty new Mint Compost from Heirloom, too :)

Thank you Outrider. At least I don't feel like I'm the only one.

That sure looks like blackspot to me. Out of everything I have tried , Mancozeb stands out as super effective.

(Disclaimer: Haven't tried the Mint Compost...waiting for someone else to take one for the team first).

Looks like blackspot...

Blackspot.