My Roses Have Terrible Black Spot; Help?

Question

This is a question for all you experienced rose-handlers, out there.

It's been so wet in Oklahoma this year, that BOTH of my roses, a baby Footloose, and a three year old Fragrant Cloud, have black-spot. The Footloose I managed to catch early, but...the Fragrant Cloud is about a fourth yellowed leaves, by now, and I'm frantic to save them.

I've put grass around their bases, and I'm spraying them about every....6 to 8 days, with Spectracide Immunox 3-in-one; they're on their second treatment, and I can't tell if its helping.

Does anyone have ANY ADVICE?

((The Fragrant cloud is a Hybrid Tea-Rose, the Footloose is a Ground-cover/Shrub type Rose.))

http://www.spectracide.com/ProductCategories/RoseAndFlowerCare/SpectracideImmunox3in1/
((And...Here's a link to the fungicide/pesticide I'm using.))

Thank-you very much for any help I get in advance. T.T

Answer 1

Black spot is caused by the fungus Diplocarpon rosae. The black spot fungus over winters in fallen leaves and in lesions on infected canes. So the treatment for the disease must include the canes or they will serve to reinfect the rose later.
Your mulch under the rose will help but is only part of the job. Dust the ground around roses with cornmeal, and water in. This helps to eliminate black spot spores that attack roses, and also helps to eliminate the spores in the soil around roses. Work in corn meal at 2 pounds of cornmeal for every 100 square feet. Water well to activate the fungus killing properties. There is a cheap, nonfood grade available at some garden centers.

Immunox uses an acropetal/basipetal bidirectional movement so is locally systemic in its effect.
I would add another to be sure not to breed resistant fungi.
Fosetyl aluminum; Aliette is the only truly systemic fungicide, moving to root and crown, so is the really bid gun in treating BS. Note that it is carcinogenic so use full precautions in spraying this.
Another group to consider is Thiophanate-methyl found in Cleary’s 3336, Domain, Halts Systemic, Greenlight Systemic, Topsin M. Class IV toxicity so much safer to humans and other mammals.
One from those two groups in addition to Immunox then you need a contact fungicide to maintain prevention once you have this infection under control.
Contact fungicides remain on the leaf surface, acting as an exterior shield. They provide a barrier to protect against infection by fungal spores so they must be applied before infection and very completely. Baking soda/horticultural oil — Tests performed by Cornell and Auburn universities in the U.S. confirm this as a good powdery mildew control. Mixed at a rate of 4 tsp baking soda (sodium bicarbonate) and 1 tablespoon horticultural oil per gallon of water, this material is sprayed on foliage and stems weekly before the disease first appears. Use caution to keep the spray confined to the plant foliage and canes, thus reducing the potential for sodium bicarbonate buildup in the soil.
Neem oil works well & is a miticide.
Sulfur and sulfur compounds — Both wettable powders and premixed solutions are currently available. But must not be used within two weeks of horticultural oil.
Come winter a dormant oil should be used in Feb & Mar or until the first leaves appear. Then the contact sprays will be sufficient and less harmful.
Vinegar Fungicide
Mix 3 tablespoons of natural apple cider vinegar in one gallon of water. Spray during the cool part of the day for black spot on roses and other fungal diseases. Adding molasses at 1 tablespoon per gallon will again help.
. Garlic naturally contains high levels of sulfur and a few cloves crushed in water can be used to make a homemade spray.
To make garlic tea, liquefy 3-4 bulbs of garlic in a blender 1/2 to 2/3 full of water. Strain the solids and add enough water to the garlic juice to make 1 gallon of concentrate. Use 1/4 cup of concentrate per gallon of spray. Add 2 T of blackstrap molasses as a sticker.

Another really good method is milk spray ...... In 1999, a Brazilian scientist found that milk helped control powdery mildew on cucumbers just as effectively as a synthetic fungicide. So far, there has been success reported on the use of milk to control powdery mildew and black spot on roses.
Any type of milk can be used from full milk to skim to powder. However, the low fat milks produce less odour. The recipe calls for milk to be mixed with water at a ratio of 1 part milk to 7 parts water and applied every 5-7 days for 3 applications.


Every leaf infected will stay that way, the black spots will not heal. You have to be patient for the rose to regrow new foliage. Spraying the rose with kelp & fish emulsion will help give it a boost towards recovering.

Answer 2

Hello sister Okie, Stillwater here. I've been growing roses for 20years now and I've never seen such black spot. My roses are down right unhappy. However, I have just come across a gardening blog in which rose growers are discussing the use of Apple cider vinegar as a defense against black spot. The fungus that causes black spot can't stand the higher pH the vinegar creates on the leaves and will not grow there. A couple weeks ago I used a commercial product that didn't seem to work that well. It slowed it down, but more leaves were infected the following week. Last week I tried the vinegar and it seemed to halt the black spot in it's tracks. I just gave my roses another weekly treatment and plan to do so until dormancy. Anyhow, if you want to try this just put 3 tablespoons of apple cider vinegar in 1 gallon of water and spray on your roses once a week. Make sure you rake up all the fallen leaves and pluck off the really nasty looking ones. This fall change out your mulch and add new. Also, remember to water at the base of your rose to help keep the fungus at bay.
Next spring you can use the vinegar as a deterrent for black spot as soon as your roses start to leaf out.

Answer 3

Treatment For Blackspot On Roses

Answer 4

Black spot can be caused by several things, insects, fungus and soil pH imbalance. In my experience it is usual an insect. My preferred treatment is Fertilomes' 3n1 insecticide, fungicide. It is different than the 3n1 you're using, i.e. it does not feed the plant and the insecticides are different. The fertilome 3n1 can be used as a systemic and topical treatment. I use it both ways for 2 weeks, then only as a once per month until the plant has new growth and shows no sign of damage in the new growth. I also insure that the underside of the foliage is wetted with the fungicide. It will take at least 2 weeks for the plant to show signs of recovery. During recovery I use a balanced, water soluble fertilizer at 1/4 recommended strength applied about every 3-4 days.

Answer 5

I read the label on the product you are using, Its ok, but I think with the wet humid conditions we are having it will take more than that. I would recommend that you go get a fungicide that will handle the black spot alone. Im fighting black spot,& aphids on my roses, powdery mildew and aphids on my crepe myrtles. Its a crazy year in Okla. so far. I use commercial use chemicals so I dont know too much about what you can get, but alternate the fungicide with what you are using. Sometimes the environmental conditions are more than any chemicals abillity to fight off disease.

Answer 6

If you live in an area that gets a lot of summer rain you probably have a serious rose disease called blackspot. It is a serious problem especially in the eastern US. You can read more on this disease by searching "blackspot of roses" If you live in a relatively dry summer area you probably have a minor fungus disease called Anthractnose usually found only on older leaves. That disease can ignored or you can dispose of infected leaves as others have suggested. I would use any fertilizer that is labeled as a rose food. Follow diretions on the label.

Answer 7

The easiest way I found to get rid of the black spot on my roses was to remove all the modern hybrids and only grow old garden roses. They have very few pest and disease problems, are much more fragrant, and are just as beautiful!