If you want to prevent bs, you need to start spraying as soon as the roses leaf out. And you need to keep spraying regularly. For prevention you can use any fungicide meant for blackspot.

Once you have blackspot, you need to use a product that can stop bs. I use the Bayer Advanced Disease Control. It will not cure the leaves that are already affected, but will stop it. I normally spray that every 3 weeks or so, depending on how the bushes look. You should see an improvement in about a week.

Also, when you spray, concentrate on the new growth so that doesn't get bs. Also, the Bayer is systematic, so you don't have to spray the underside of the leaves as you do with other fungicides in order to get the protection there. IT will be absorbed into the plant to protect it internally.

I am in 9ab Florida.I spray from End of Feb. until beginning of Dec..I spray every week during this period.I use the Bayer advanced garden disease control at the rate of 1 and 1/2 tablespoons per gal.
Cutting to the chase after several years of spinning wheels and backing and filling,I find this gives me zero signs of blackspot.
You aren't going to improve on perfection[zero blackspot].
Since this product kills and controls blackspot you need that frequent of spraying to keep the disease from activating in my yard.lol.In other areas with different temperatures and humidity levels I gather you can use different routines.
Its a nuisance and costly but all I have to do is look at other peoples roses to figure its worth it to me.
I have no proof but feel that roses sprayed to keep them disease free have much more vigor.

Thanks, Pete and buford. I was looking for y'alls response, particularly. If I continue to spray every 7-10 days, will my black spot go away?

If you use the Bayer,it should.
It can not reverse the process of course but if you have blackspot-watch what happens,after you spray.
It will turn grey and crumble at that point.The fungus is dead but the leaf is still alive if it hadn't progressed too far.What you can do is pick a couple of bushes that BS and use them as a test to see how long you can go between spraying and the rest as a control.Spray the majority once a week and the test ones two weeks.If you can get along with the longer period-fine.If not keep loping off a day.

Go to the Rosmania (Rosemania.com) website and take a look at all their fungicides. They have some good explanations of what each product does and how often it should be used. One year I had a terrible time controlling blackspot and followed their advice to spray Manzate (a contact fungicide that kills blackspot) 3 times in a row, 3 days apart,thereafter going back to a routine of using the systemics. It worked.

I rotate the systemic fungicides. The Bayer products work excellent, as does Honorguard (same as Banner Max-slightly less expensive), and Compass.

Sandy

I guess what I'm asking is, if I see a black spot on my leaves, is it too late for the fungus/disease to be cured, even if I have been spraying every week? Seems like no matter how often I spray (according to the label) the next day I have leaves with black spot.
Amy

amy, I stopped spraying last October, per usual. But it stayed warm and I had blackspot very bad on most of my roses. Some of them carried it into the spring, especially my climbers that don't get pruned that much.

The Bayer took care of it. I would do it one week and see how it does. If you don't see an improvement, spray the next week. But really, I don't think you need to spray every week. Just be careful with the concentration, follow the directions. One time I got over zealous and used a higher concentration and really sprayed a couple of very disease susceptible roses too much. The leaves on these bushes curled and didn't look right.

If I do have bs and there are dropped leaves on the ground, I also spray that to kill any spores on the dropped leaves. That also helps prevent the spores from getting back on the leaves.

I don't think it's that expensive. A bottle of concentrate is about $14 and lasts me a whole season. I have about 70 rose bushes, a lot more than last year,so maybe I'll need 2 bottles this year.

Amy-are you sure you are seeing blackspot??????/
Might you be mistaking the leaves that turn yellow and have very dark green spots.These are leaves that the plant is shedding in the growth process.If thats a possibility I will try to get some pictures and non-sprayers can post some of blackspot.If you have been using Bayer hard to believe you are still getting Blackspot.
With banner-maxx its possible-why I switched.

If you are using a regular fungicide, you will still have bs. That's why you have to begin those at first leaf till they defoliate. Because once you get it, it's almost impossible to get rid of (with regular fungicides).

All this worrying about bs is also why some of us insist on planting only disease-resistant roses in our gardens. Even disease-resistant roses can get bs sometimes, but at least they cut down on all the worrying and fussing. Let's face it--some roses are disease-magnets. No matter what you do, they are always coming down with bs. Those are the ones you should throw out of your garden as fast as you can.

Can you tell us the names of some of your roses? Maybe we can help you identify the ones that are going to give you regular bs headaches.

Kate

First of all, I don't remember posting the phrase 'no arguing' in my subject line. Is there a moderator that might have changed my subject line...or have I had too much wine?? Anyhow, my main offenders of black spot are Just Joey, Peace, Wild Blue Yoder, Disneyland (I think this is the name of the rose...I inherited it), Aromatherapy, Lavender Simplicity, and the yellow ground cover from J&P that I can't remember the name of, and all of my mini's. My Iceburg tree's, Simply Marvelous, and Moondance are uninfected. Pete, I'm (pretty sure)it's bs, but I will post pictures soon. Please check back.
Amy

I understand that new mulch under the roses are helpful and I put newspaper under that.

I've been reading about new mulch also, but I hope this is not necessary b/c that could be somewhat costly. zyperiris, have you tried this with any luck?
Amy

What new mulch will do is cover any spores hanging out under the roses (the spores then splash up onto the rose foliage when it rains, or so I've read). When I first started with roses, I read that you should replace all the mulch every spring. Yeah, right, who's going to do that!

Some of the roses I have that have good resistance are, Diana Princess of Wales, Rose Rhapsody and Melody Parfum. Although all had some last fall and even a bit this spring, perhaps because they were weakened by the freeze.

The worse ones for me are Iceberg, Golden Showers, Ballerina, and of course Peace and Double Delight.

I have planted many Austins and some OGRs, but it's too soon to tell how resistant they are.

amy, I vote for too much wine :)

Amy, you don't say which fungicide(s) you are using, that would help answer some of your questions.

Blackspot is ALWAYS PRESENT. Remember that. ALWAYS. What you are doing with your fungicide sprays is to assist the plant in resisting the outbreaks. You want to start spraying as soon as possible after pruning. I usually start a week or two after. And keep on schedule. YOu might have to shorten your schedule, depending on the amount of blackspot pressure in your area, you may have to spray every 7 days instead of 10 days.

Once blackspot emerges on the leaves, the lesion will always be present on that leaf. That does not mean that the outbreak will spread, depending on the fungicide that you are using. You might need to add a contact/surface fungicide in order to control any active blackspot.

I can't find the original thread, but Mike Rivers posted this information about the different types of fungicides and mode of actions, this might help you.

RE: Blackspot (Follow-Up #1)
posted by: mike_rivers on 03.10.2007 at 08:40 am in Roses Forum

I'm assuming you plan to use modern synthetic fungicides. Your choice of weapons are:
1) Systemics. These inhibit germination of BS spores and some, maybe all, also kill an established infection. The most popular seem to be propiconazole (Banner Maxx, Infuse), tebuconazole (various Bayer products) and myclobutanil (Immunox). These three all have the same mode of action (MOA) and it is pointless to rotate among them - pick the best (either propiconazole or tebuconazole, in my opinion) and stick with it. Performance of each is improved with addition of a spreader-sticker (I just add two tsps of any liquid dish detergent per gallon to act as a spreader, you can tell if you need a spreader by examing the sprayed leaves for a uniform film of wetness, rather than beads of spray) Compass is a more expensive systemic which has a different MOA.

2) Surface Fungicides. The most popular seem to be Mancozeb or Manzate and Daconil. These sit on the surface of the leaf and are not absorbed into the plant, mostly because they are very water-insoluble. This, in turn, means they are sprayed as an emulsion rather than as a water solution. They function by killing spores, perhaps on contact or perhaps during the germination stage. They are not supposed to kill an established infection. Daconil can be phytotoxic to the leaves, especially during hot weather and Mancozeb is worthless unless your tap water is adjusted to an acidic pH close to 5.

A reasonable way to conduct your warfare is to use the minimum force necessary. The backbone of your campaign should be a systemic. I would suggest Banner Maxx sprayed biweekly, from leaf-out to leaf-off, as a start. This is all it takes to obtain satisfactory control in my garden. If that isn't sufficient, move up to weekly application. If that isn't sufficient, then you could rotate in a surface fungicide and so forth. In BS hell, you might also want to rotate in Compass and include a dormant-season application, typically lime/sulfur or one of the above surface fungicides.

No offense meant but in blackspot hell forget the others and go with the Bayer.Its the best and its also one product kills and controls.
You aren't going to improve on zero visible blackspot and thats the result faithful Bayer users get down here in BSH.lol

Ok, thanks everyone. I was using Bayer and I switched to Infuse, but maybe I'll give Bayer another try. Would alternating between the two make a difference?

So far haven't heard of Bayer becoming immune to.[That sentence reflects Pennsylvania Dutch heritage]lol.
If I try to stretch Bayer to 8 or 9 days my protection fails.I would stick with it and have a weekly spraying.If that fails I would take a sample to State lab.Could be something else.

There is some misinformation on the Rosemania site (unintentional, they are a good company). Good advice higher in this thread to use a fungicide containing propiconazole or tebuconazole immediately and continue at regular intervals-- at least every two weeks until the disease is under control. Possibly the best choice would be Bayer Advanced Disease Control containing only tebuconazole, which can be applied weekly (if needed during an outbreak) without harmful effects on the plants.

Some fundamentals: blackspot carries over winter primarily as lesions on the old canes, secondarily in fallen leaves, and in zone 9 on evergreen leaves. It is not a soil disease. Picking up fallen leaves and refreshing the mulch is useful sanitation, but not necessary if you use a systemic fungicide. Blackspot usually appears first on the lower leaves because these are closer to the old canes and fallen leaves. Once established in the foliage, the disease can move rapidly from leaf to leaf. Spores are not normally airborne, but are carried mainly by splashing water and the gardener's hands. Spores germinate only after long continuous soaking at moderate temperatures (60s and 70s), which typically happens overnight in warm seasons, or during the day in spring and fall. Fungicides like mancozeb act by killing spores during this process of germination, if there is a complete film of fungicide on all leaf surfaces.

After germination, the fungus develops inside the leaf. Spots become easily visible in about two weeks. After perhaps a month, the leaf will be damaged irreversibly. Systemic fungicides can prevent germination, but if germination has occurred, they can kill the fungal body inside the leaf. The leaf will then survive if the damage has not progressed too far. Tebuconazole (in Bayer) has been shown to arrest blackspot infection if applied even 19 days after inoculation of the leaf with the fungus.

When you spray during an outbreak, there will be infections at different stages. If you use mancozeb or Daconil, spots can continue to appear for two weeks from previous infection. Even with systemics, severely injured leaves will still continue to die from old infections causing irreversible damage.

You need to determine for sure whether your spots are from spray damage, blackspot, or some other disease. Blackspots have notchy or fringy edges.

Amy, regarding your last post, as Mike_Rivers said, propiconazole and tebuconazole (Infuse and Bayer) are too similar for there to be any benefit from rotation. If you spray Bayer weekly for a month on every leaf, your outbreak should be controlled.

For future reference, after I have planted my bare roots, how long must I wait before I begin spraying them? My mom had cautioned me against spraying them too soon. Obviously I want to avoid that. I'm thrilled to see that Diana Princess of Wales is bs resistant. I've been wanting that one for a long time and that is all the reason I need to get it next season.
Amy

I've generally sprayed bareroots as soon as they leaf out (some leaves fully expanded), and that's often been with stuff more likely to burn than Bayer. Roses from pots are more likely to burn because they are more likely to run out of water. In fact, they may burn in the sun even without spraying. If you have susceptible roses in an area of high disease pressure, you need to spray them anyway, starting a week or two after planting, IMO, and watering moderately every other day.

NC chiming here.It's been a very hot and humid summer here. I recently moved and took several rose bushes with me. This is the first year since growing roses I have not been plagued with black spot hell. Well maybe one has a little bit and that would be Ballerina. The others are Tamora, Heritage, Sharifa Asma, Cherry Parfait, Tiffany, Grenada, Veterens honor, Virginia, Dream weaver, Cherries n cream, Mary Rose, Guinevere, New Dawn and Sally Holmes. I have been using Immunox 3 in 1. I spray about every 7 - 10 days I am still amazed at how my roses look. Usually by this time of year they have a lot of black spot or are completely defoliated. So I am gonna stick with the immunox for now. Kills the JB's too.

Tammy

I always spray in the morning when the leaves are a bit dewey and before the sun hits them full. I've never had them burn.

Also and electric sprayer that can deliver a very fine mist coats the leaves without drenching them, and cuts down on the amount of solution you need.

Whatever you do, don't use a hose end sprayer, unless you have a HUGE climber that needs spraying.

Where ever there is humidity you will have blackspot, no getting away from it. I use the Bayer Advanced Disease Control Concentrate. I mix 1 1/2 TBS. with 1 gallon of water in one gallon spray bottle. I spray in the evening 2 hours before it gets dark. I make sure my roses are well watered the day before or that morning I am spraying. Last year my Ambridge Rose had BS very badly. I sprayed the Bayer ADCC every other evening for 3 days. It worked great, no trace of BS. You have to try and remove most of the infected leaves that you can. Also a very important thing to remember is to wash your hands after handling an infected bush. Do not go from bush to bush after touching the blackspot leaves.

I hope someone is still reading this thread that can help me.

I have terrible, terrible, black spot and maybe some other spot that has gone out of control. Almost all leaves are gone on many bushes and infection is spreading to others. The bushes where most leaves are gone look very weakened.

Reading on Gardenweb I have so far hurriedly bought a Ortho product with chlorothalonil in it which I hear is the same as Daconil. I have ordered Mancozeb. I will be using Mancozeb every three days as suggested. And I should alternate the two?

The next product I should get is Bayer Advanced Disease Control, right? or Banner Maxx? And I should use the Bayer product after I have used Mancozeb for a while?

I am still confused how to go about this.

Your help is so appreciated!

I clean up active blackspot by spraying with mancozeb 3 times, with 3 days between each spray. I then return to my regular spray schedule of BannerMaxx/mancozeb/Indicate5 (pH balancer with sticker properties to hold the products onto the leaves, some people use dish soap instead)/liquid seaweed. I "usually" spray my regular mixture every 14 days (I've been very lax in spraying this year).

Many people use Bayer Advanced Disease Control as both the contact and the systemic. Michaelg noted above that spraying the Bayer product weekly for a month will get control over the blackspot and provide the systemic properties needed to control future outbreaks. Others will have to chime in on this as I am not well-versed on the Bayer product.

You don't need to alternate between the Ortho Garden Disease Control and the mancozeb, it won't buy you anything. Just a note, though, that the Ortho product can burn at temps over 80 degrees, but mancozeb does not burn. You will also need a few drops of dish soap in the mancozeb solution to hold it on the leaves.

Thank you so much Diane. I just ordered Bayer Advanced Disease Control. I am getting the hang of it now (in my mind). Just wondering if my roses will make it till all sprays arrive.

Katyajini

Your roses will be fine. Just start your spray program when you get your stuff, and pick off any infected leaves. They'll bounce back.

Sandy

I would not replace all my mulch..I just put new mulch on top..

I will maintain this garden but we are moving as my MIL passed away on July 4th. We will close out her estate her and move..then I will plant lots of new roses..let me tell ya..if that yard will not handle 100 roses then I am not moving there

Sorry for your loss.

Bill

zyperiris, sorry about your mother in law.

Hope the move goes well, and good luck planting all the new roses.