Roses forum→How to stop black spot

Views: 411, Replies: 19 » Jump to the end
Guam
aliciah
Dec 12, 2020 5:18 PM CST
Can someone help me control black spot. I tried Safer, mancozeb, copper, Bayer bio advance insect spray. Not working. Was told to remove leaves and do regular cleaning . Spending hours to do all these, everyday and this pest seems uncontrollable,
Any advice?
Thank you
Alicia
Name: Suzanne/Sue
Sebastopol, CA (Zone 9a)
Sunset Zone 15
Plant Database Moderator Region: California Cottage Gardener Garden Photography Roses Clematis
Houseplants Foliage Fan Keeper of Poultry Dog Lover Birds Hummingbirder
Image
Calif_Sue
Dec 12, 2020 5:40 PM CST

Moderator

What plant? Roses?
My gardening Blog!
Handmade quilts, face masks, new & vintage fabrics in my Etsy store. Summer Song Cottage
Instagram Sewing posts
Livonia, Michigan (Zone 6a)
He who dies with the most toys wins
Region: United States of America Critters Allowed Growing under artificial light Echinacea Hostas Region: Michigan
Butterflies Lover of wildlife (Raccoon badge) Orchids Cat Lover Birds Bee Lover
Image
BigBill
Dec 12, 2020 6:17 PM CST
Copper can kill a lot of plants so I would never use it on anything.
If you are asking about fungal black spot, an insecticide like Safers or Bayers bio advance won't do a single thing.

You spraying something everyday is just you panicking. It won't cure a thing. Curing insects or fungal problems take a little time. You can't rush it! All of these chemicals might harm the plant far worse then the black spot!!!
Images images images please!
The key to orchid growing is to match the orchid to your conditions.
Guam
aliciah
Dec 13, 2020 1:10 AM CST
To BigBill/ Thank you so much for responding. I sprayed after 12 to 14 days or after it rained. My roses plants are 10 and 8 months old. Do you spray them with something else? What do I do?
Thanks Alicia


To: Suzanne
Yes sorry it's for Rose plants .
Alicia
Name: Lynda Horn
Arkansas (Zone 7b)
Eat more tomatoes!
Lover of wildlife (Raccoon badge) Container Gardener Lilies Cat Lover Lover of wildlife (Black bear badge) Zinnias
Organic Gardener Heirlooms Bee Lover Hummingbirder Echinacea Tomato Heads
Image
gardenfish
Dec 13, 2020 3:01 AM CST
First, please understand that once roses get blackspot, there is no cure, so what you are doing is controlling it. I have no issues with copper. I've used it for two years, not only on my roses, but other plants with fungal issues and no damage to plants. I would like to say there is potential plant damage that could occur from using ANY type of product, whether it is copper, a systemic, Neem oil or manzoceb. ,The decision to start spraying plants with anything should always start with a correct analysis of the problem. That's where pics of your rose leaves would be very helpful.
I've had numerous black spot discussions on various threads in the rose forum, and while most of our rose growing members agree that black spot is incurable, their recommendations of treatment vary according to their growing conditions and personal experience. Some members have had success with systemic, some with name brand fungicides, while others, like me, prefer copper.
One area of agreement over all is that any infected leaves that fall to the ground must be removed and destroyed, and that it's highly recommended that when spraying roses, the product needs to be sprayed on the ground/ mulch surrounding the bush, in a circle of around two feet.
The treatment of stripping all leaves from the bush has come up recently, IMO, it's too radical, and the result is to weaken the plant further and possibly add to the plants demise, yet I know of a member that does this and has beautiful roses.
I do agree that throwing everything but the kitchen sink at the plant, one product after another, is counterproductive and could seriously weaken the plant further. It's best to carefully choose a product and stick with that one for a specified amount of time before switching to something else.
Personally, I switch products every two to three years because it seems that black spot becomes somewhat immune to the same product used over a long period of time. I also spray the bushes and the ground with dormant oil after my first hard freeze; this was recommended to me by a respected horticulturist in my state.
As with anything that you would apply to a plant, whatever fungicide you choose to apply should be according to the instructions of that product. Many gardeners think that if a a little is good, a lot is great, but this only increases the possibility of damage to the plant.
Choosing a fungicide is therefore mainly a matter of choice. A phone call to your local extension agent is an excellent idea; he/she might be able to tell you what works well in your area. If you choose a systemic product, be sure to pick one that does not contain Imadicloprid, this ingredient has been found to damage honey bees.
“ Be kind whenever possible”
14th Dalai Lama
Guam
aliciah
Dec 13, 2020 4:13 AM CST
Hi Lynda
GARDEN FISH

THank you so much. Yes it becomes a dedication to ensure I clean the dropped sick leaves on the ground. It's too much that I can't be sure I missed some. Yes, it needs more mulch since I last put them around. It also rains always and humid on most days. Again thanks.
Name: Lynda Horn
Arkansas (Zone 7b)
Eat more tomatoes!
Lover of wildlife (Raccoon badge) Container Gardener Lilies Cat Lover Lover of wildlife (Black bear badge) Zinnias
Organic Gardener Heirlooms Bee Lover Hummingbirder Echinacea Tomato Heads
Image
gardenfish
Dec 13, 2020 4:16 AM CST
You're welcome! I just noticed where you live; very warm and humid! A perfect place for fungal diseases. Good luck with your roses!
“ Be kind whenever possible”
14th Dalai Lama
Name: seil
St Clair Shores, MI (Zone 6a)
Roses Garden Photography Region: Michigan
Image
seilMI
Dec 13, 2020 6:09 PM CST
Alicaih, you need to know that spraying once you have disease symptoms will only protect new growth. Any leaves that have already been infected, whether they have symptoms or not, will not get better. They will continue to spot, yellow and fall off until ALL infected leaves are gone. Don't assume any green leaf is not infected but do not remove the green ones until you know if it is infected or not. The plant needs those leaves to continue photosynthesis to feed the plant. After spraying the protected plant will then regrow healthy leaves. So spraying every day is a waste of time, money and energy. You have to wait for the new clean growth to happen. Follow the package directs on how often to spray to keep your roses looking their best.
Name: Lynda Horn
Arkansas (Zone 7b)
Eat more tomatoes!
Lover of wildlife (Raccoon badge) Container Gardener Lilies Cat Lover Lover of wildlife (Black bear badge) Zinnias
Organic Gardener Heirlooms Bee Lover Hummingbirder Echinacea Tomato Heads
Image
gardenfish
Dec 13, 2020 6:20 PM CST
I agree Seil knows what she's talking about. She grows beautiful roses.
“ Be kind whenever possible”
14th Dalai Lama
Name: seil
St Clair Shores, MI (Zone 6a)
Roses Garden Photography Region: Michigan
Image
seilMI
Dec 13, 2020 6:31 PM CST
Aw, thank you, Lynda, so do you!
Name: Lola
Tasmania
Keeps Sheep Roses Cottage Gardener Garden Photography Birds Farmer
Image
LolaTasmania
Dec 13, 2020 7:09 PM CST
It is also wise to grow plants that are more disease resistant. I had a few roses that were prone to blackspot so I replaced them with ones that were considered to be far less prone to it. Help Me Find Roses and the database here have a heap of information from members about the health of different rose varieties in different climates. If there is a rose society near you they should be able to advise you too. Just because a rose is available to buy in your area that doesn't mean it suits your climate.
Guam
aliciah
Dec 13, 2020 8:01 PM CST
To: SeilMe and Lola,
Thank you very much! Your information and advices are highly appreciated.
Aliciah
Minnesota (Zone 3b)
RpR
Dec 15, 2020 12:02 PM CST
As usual pick off infected leaves, if you do not the plant is trying to support leaves already on life support rather than healthy leaves, then treat with a Bio-fungicide, designed to stop Black Spot and other SIMILAR nasties.
Do not use the wonder this , that or the other thing products, as Bayer, and others offer.
It IS a good idea to find several types of Bio-fungicide and alternate , at least yearly so the nasties cannot adapt to the same old, same old.
In your climate you will probably have to treat often , weekly, not just spraying the top of the plant but under the leaves, and DOUSE the ground around the plants monthly till you have it under control.
Be careful when you buy plants they do not come pre-infected. I have had clear beds screwed up by a high bucks infected rose.
I use Serenade, Sonata, Oxidate and Actinovate but am always on the lookout for another to keep the nasties off balance.
[Last edited by RpR - Jan 12, 2021 7:43 PM (+)]
Give a thumbs up | Quote | Post #2399076 (13)
Name: aka Annie
WA-rural 8a to (Zone 7b)
Sandsock
Jan 5, 2021 12:20 PM CST
I had BS and very small children and found that milk spray worked about as well as anything...cheaper and safer: 60% milk to 40% water...Since found they have done studies that shows it is almost as effective as anything else...I still go with safe, cheap, easy to get from my fridge: milk.

You will have to go with what you feel fits you.
Minnesota (Zone 3b)
RpR
Jan 6, 2021 10:46 AM CST
Sandsock said:I had BS and very small children and found that milk spray worked about as well as anything...cheaper and safer: 60% milk to 40% water...Since found they have done studies that shows it is almost as effective as anything else...I still go with safe, cheap, easy to get from my fridge: milk.

You will have to go with what you feel fits you.

I have read that in several places but as I use two five gallon pails, on average when I apply and at the two to one ratio , that means , minimum two gallons of milk each time I do it.
Well at three plus dollars a gallon, I would be spending 40 to 50 dollars on milk in the summer for application.
I buy the two and one-half gallon jugs of bio-fungicide, 100 bucks, plus or mins 20 depending on brand, which lasts years and by my calculation saves a lot of money.
As I said earlier , use BIO-fungicide, not some whiz-bang miracle cure.

Guam
aliciah
Jan 11, 2021 3:05 PM CST
Thank you so much.
I had given up on those whiz bang miracle cure and so depressed looking at my rose plants that once so healthy. And envied by neighbors jogging by .
I will try the milk. Thank you so much.
Name: Rj
Just S of the twin cities of M (Zone 4b)
Garden Ideas: Level 1 Plant Identifier Million Pollinator Garden Challenge
Image
crawgarden
Jan 11, 2021 3:09 PM CST
Guam, would be a difficult spot with all of the humidity and daily afternoon thunderstorms, excellent location for tropicals.
Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed.
Guam
aliciah
Jan 11, 2021 4:43 PM CST
Hi would you kindly provide me how many times to spray milk as suggested?
Re spray if it rains?
Twice a week!
Every 7 days? 10 days?
Thank you so much.
aliciah
Name: Rj
Just S of the twin cities of M (Zone 4b)
Garden Ideas: Level 1 Plant Identifier Million Pollinator Garden Challenge
Image
crawgarden
Jan 11, 2021 4:51 PM CST
https://www.hunker.com/1255247...
Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed.
Name: SoCal
Orange County (Zone 10a)
Lazy Gardener
Image
SoCalGardenNut
Jan 11, 2021 4:59 PM CST
Interesting, I also use milk and water for mildew too, 8:1ratio. But for BS, I just removed all the leaves and they started over again without any problem. I'm in California so roses grow year round.
I try to grow everything, sometime not successful.
[Last edited by SoCalGardenNut - Jan 11, 2021 5:16 PM (+)]
Give a thumbs up | Quote | Post #2414695 (20)

« Garden.org Homepage
« Back to the top
« Forums List
« Roses forum
Only the members of the Members group may reply to this thread.

Member Login:

[ Join now ]

Today's site banner is by Char and is called "Phlox paniculata Flame Pink"

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.