Suggestions for Black Spot

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Author Message   Carolyn  Posted on Monday, November 04, 2002 - 07:33 pm EST :    I really love roses but they dont do very well in this semi tropical climate. I think the humidity gives them that horrible black spot. Do your roses over there get it. I use a rose dust which is a combination for bugs and fungus. Does anyone have any other suggestions. Carolyn Carolyn - Queensland, Aust. Semi-tropical   Ej  Posted on Monday, November 04, 2002 - 08:02 pm EST :    Carolyn I use a spray, I place them on a routine schedule. Maybe swamprose would chime in? EJ Southern California Zone 10a   Swamprose  Posted on Tuesday, November 05, 2002 - 06:35 pm EST :    I don't use fungicides or pesticides because I don't want chemicals in the garden, so I don't plant HTs, which are the worst for BS. The first thing I find out about a rose is how resistant it is to blackspot. If it doesn't have decent resistance, I just don't buy it. I planted all HTs when I first started and shovel-pruned most of them, except for Tiffany, which I spray once in a while with Miracid, which seems to help. Her blooms are so pretty I put up with a lot from her leaves. SwampRose western WA Zone 8   Phyllis66  Posted on Sunday, November 10, 2002 - 06:35 am EST :    Wish I could be of some help Carolyn. I spray mine with baking soda ( mix it with water) or Listerine (half Listerine half water)for mildew, rust and black spot. Have no clue if it will work where its so Tropical..You could try it.... phyllis66 zone 9 So.California   Tony  Posted on Monday, November 11, 2002 - 05:48 am EST :    New Orleans area is known by some as the rain capital of the world Roses that are resistant to black spot and other fungal infections are not only susceptible but guaranteed to have it in time. I use a ten day rotation of Dithane M 45 powder (contact)and Banner Maxx (systemic) for control. Works real well. Tony Tony Louisiana 8-B   Swamprose  Posted on Monday, November 11, 2002 - 08:17 am EST :    Tony, have you tried Knockout? It's the most BS-resistant rose I know of, and it has never had a speck of BS here. I don't spray it with anything at all. Its leaves are absolutely perfect, all the time, even in the rainy season. I would be curious to know how it does for you there. (hey, I thought I was in the rain capital of the world western WA Zone 8   Tony  Posted on Monday, November 11, 2002 - 08:34 am EST :    Hi Swamprose Yep it does get rainy and humid here. Of my 90 rosebushes only a few of my old garden roses, like Mutabilis and Little Pink Pet are BS free. I have tried many products, with varying success. Daconil is great but causes leaf burn in my zone. I will look up your suggestion, thanks. Tony Louisiana 8-B   Phyllis66  Posted on Monday, November 11, 2002 - 12:02 pm EST :    You are right Swampy, I have 3 'Knock Outs' none of them have every had any thing but blooms upon blooms. Almost year round for me here in So. Cal.As you can see by the Photo, the plant is clean. Worth a try Tony...;)SwampRose knows her stuff. phyllis66 zone 9 So.California   Swamprose  Posted on Monday, November 11, 2002 - 12:58 pm EST :    phyllis, your rose pics are so pretty, just what I need to see today...my garden has no color now. Lucky you to have them bloom most of the year. I can't even imagine that! western WA Zone 8   Clary  Posted on Saturday, November 16, 2002 - 09:16 am EST :    Carolyn, Here's the recipe for the "Cornell University Formula" I garden organically and this is what I use. I don't know about the availability of some of the ingredients in your area. This is a good "all around spray" for powdery mildew (fungi), spider mites, aphids, etc. and the superthrive and seaweed make it good for the foliage also. Organic Spray Formula: Mix into one gallon of water, in the order listed: 1 tbsp. of mild dishwashing soap (such as Palmolive green -- but see note below) 2 tbsp. of ultrafine horticultural oil (such as Sunspray™ oil) 1 heaping tbsp. of baking soda 1 tbsp. of fish oil/seaweed emulsion 3-5 drops of Superthrive® If needed, add the label recommended dosage of Bacillus thuringiensis (Bt) for control of caterpillars. [Note: Labels on newer containers of Sunspray™ oil indicate that it now contains an emulsifier. In that case, the dishwashing soap can be omitted.] Mix well and spray with a pump-up sprayer late in the evening, after first watering your roses thoroughly and spraying them with the hose to scare off some, most, or all of the beneficial insects. DON'T ADD VINEGAR. NEVER USE ANY TYPE OF FISH OIL/SEAWEED PRODUCT CONTAINING SULFUR WITH A HORTICULTURAL OIL SPRAY. AND NEVER MIX A CHLOROTHALONIL FUNGICIDE (e.g. Daconil™ or Fung-onil™) WITH HORTICULTURAL OIL OR USE THEM ON ANY PLANT WITHIN 10 DAYS OF EACH OTHER. For black spot control, it is important that you spray all of the plant's wood, as well as the foliage. It has been found that the black spot spores reside in lesions in the canes and that they attack, not only the foliage, but also the canes and prickles. Clary   Swamprose  Posted on Sunday, November 17, 2002 - 06:27 pm EST :    Clary, have you really noticed a difference in BS when using the formula? I tried it a couple years ago. It seemed to help at first, but then it didn't really seem to make any difference whether I used it or not, so I stopped using it. I think I used it for one whole season. How long have you been using it? SwampRose western WA Zone 8   Clary  Posted on Monday, November 18, 2002 - 11:19 pm EST :    SR I've only started using it this season. Notice a definite improvement on powdery mildew on the English Sachet and Black Spot on the leaves of my Zeph. Still have some signs of black spot (I guess that's what it is) on the canes of the Zeph. I'm really not very deligent with my spraying. Whenever I see one that needs it I just shot em all. I will probably shot everything when all the leaves drop. I should be able to give you a better answer as to if I think it was effective in the spring. Now you need to keep in mind SR I'm new at roses...I don't have the experience you have...I'm just fumbling my way through and learning as I go. I'm always open to suggestions and opinions. Clary   Swamprose  Posted on Thursday, November 21, 2002 - 08:41 am EST :    Clary, I'm looking for suggestions and opinions too! :o) I only used it for a season, maybe not long enough to see if it really works. I've removed the roses that regularly defoliated from BS and replaced them with less fussy roses, so BS isn't really a problem in the garden now. Would be interested to see how yours does over time with the Cornell formula though. I've heard good and bad things about it, but suspect people mix and spray it differently too, which could account for the differences in results. SwampRose western Washington zone 8   Carolyn  Posted on Saturday, November 23, 2002 - 03:04 am EST :    Thanks for the recipe Clary. Tamborine Mountain, Queensland, Australia - Semi-tropical   Phyllis66  Posted on Saturday, November 23, 2002 - 04:36 am EST :    Good of you to post that formula Clary, I will be trying it, as I garden organically also.. & phyllis66 zone 9 So.California   Ronda  Posted on Friday, November 29, 2002 - 08:32 pm EST :    I have been told that when days AND nights are above 70 degrees, blackspot cannot spread. I do spray a bit, but because of our warm temps only have to spray in spring and fall. I have had fantastic foliage all year. Just now one of my roses shows some BS. Not enough to even drop leaves, so I just let it be. I haven't sprayed in a long while. HTH ~~ Ronda Upstate SC Zone 7a ~~

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