Ask a Question forum: Coleus new mildew disease

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KarenKees
Mar 5, 2016 6:05 PM CST
Have any coleus enthusiasts found a cure or treatment for the new mildew disease that is destroying coleus? it just reached my Southern California garden last summer. Unfortunately, I didn't know about the mildew and brought it home on a nursery plant. Now, my entire grounds and all my mother plants are infected.
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Name: Karen
NM , AZ (Zone 7b)
Region: New Mexico Region: Arizona Greenhouse Cactus and Succulents Adeniums Garden Art
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plantmanager
Mar 5, 2016 6:07 PM CST
Darn, I don't know anything to help, but I love your Coleus garden! That is gorgeous! I hope there is a solution. They are such nice plants.
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Name: Jennifer
48036 MI (Zone 6b)
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jvdubb
Mar 5, 2016 6:08 PM CST
Welcome! KarenKees

I have not heard anything about this. We are still in the midst of the mildew epidemic of impatiens here. Very frustrating. I'll have to research the coleus problem
[Last edited by jvdubb - Mar 5, 2016 6:09 PM (+)]
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Name: Caroline Scott
Calgary (Zone 4a)
Charter ATP Member Region: Canadian Bulbs Winter Sowing Enjoys or suffers cold winters Lilies
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CarolineScott
Mar 6, 2016 7:54 AM CST
I wonder if a spray with dilute peroxide would help?
Just an idea---I have no experience with it.
Name: Tiffany
Opp, AL (Zone 8b)
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purpleinopp
Mar 6, 2016 7:58 AM CST
Hi & welcome, Karen! Your gardens are magnificent!! I'm blown away!

So sorry to hear the mildew has found you. I heard about this a few yrs ago & haven't bought any new Coleus since. From what little I understand about it, it can't thrive in high temps. The links have some suggestions for treatment.

Here's some info on this awful downy mildew:
http://www.greenhousegrower.com/production/crop-inputs/resea... (worth waiting for the ad, IMVHO)

http://pnwhandbooks.org/plantdisease/coleus-solenostemon-spp...

Some other colorful plants you might like...
Perilla
Perilla (Perilla 'Magilla')
Perilla (Perilla 'Magellanica')
Iresine herbstii (a red plant)
Beefsteak Plant (Iresine herbstii)
Hypoestes (comes in white, pink, red)
Polka Dot Plant (Hypoestes phyllostachya)
Tradescantia zebrina (purple/green/gray stripes)
Inch Plant (Tradescantia zebrina)
Tradescantia pallida (a purple plant)
Purple Queen (Tradescantia pallida)
Tradescantia spathacea (dramatic purple back of leaves, various pink stripes)
Oyster Plant (Tradescantia spathacea)
Begonias (too many to paste links to, various rhizomatous, wax, and cane types are amazingly colorful and easy to care for)
Alternanthera (various)
Calico Plant (Alternanthera ficoidea 'Partytime')
Ruby Leaf (Alternanthera dentata 'Purple Knight')
Joseph's Coat (Alternanthera ficoidea)
Joseph's Coat (Alternanthera ficoidea 'Red Threads')
Alternanthera ficoidea 'Snowball'
(and many others in the plant database in search for Alternanthera.)
Breynia
Snow Bush (Breynia disticha)
Euphorbia tithymaloides (dramatic pink highlights)
Variegated Devil's Backbone (Euphorbia tithymaloides 'Variegatus')
Bromeliads & earth stars (too many colorful/variegated ones to link)
Aglaonema (Chinese evergreen, many colorful cultivars)
Gynura (a fuzzy purple plant)
Purple Velvet Plant (Gynura aurantiaca 'Purple Passion')
Plectranthus (various variegated ones)
Variegated Cuban Oregano (Plectranthus amboinicus 'Variegatus')
Plectranthus (Plectranthus discolor 'Green & Gold')
Plectranthus (Plectranthus forsteri)
Stromanthe Stromanthe (Stromanthe thalia 'Triostar')
Codiaeum (Croton)
Croton (Codiaeum variegatum)
Cordyline (Ti plant)
Ti Plant (Cordyline fruticosa) (look at individual cultivars too)

๐Ÿ‘€๐Ÿ˜๐Ÿ˜‚ - SMILE! -โ˜บ๐Ÿ˜Žโ˜ปโ˜ฎ๐Ÿ‘ŒโœŒโˆžโ˜ฏ๐Ÿฃ๐Ÿฆ๐Ÿ”๐Ÿ๐Ÿฏ๐Ÿพ
๐Ÿ€๐Ÿ‘’โ˜€๐Ÿ„๐Ÿ๐ŸŒฑ๐ŸŒฟ๐ŸŒด๐ŸŽ„๐Ÿ‘ฃ๐ŸŒต๐ŸŒทโš˜๐ŸŒน๐ŸŒป๐ŸŒฝ๐Ÿก๐Ÿƒ๐Ÿ‚๐ŸŒพ๐ŸŒฟ๐Ÿโฆโง ๐Ÿƒ๐Ÿ๐Ÿ‚๐ŸŒพ๐ŸŒป๐ŸŒบ๐ŸŒธ๐ŸŒผ๐ŸŒน๐ŸŒณ๐ŸŒฒ
โ˜•๐Ÿ‘“ The only way to succeed is to try.
Name: Ken Ramsey
Starkville, MS (Zone 8a)
[url=www.tropicalplantsandmore.com]
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drdawg
Mar 6, 2016 8:19 AM CST
That is sure a gorgeous landscape scene, @Karenkees. Three fungicidal products come to mind, Daconil, Immunox, and Neem Oil. I don't grow coleus so you would have to check on the labels to make sure the fungicides are safe to use on them.

Welcome to ATP.
drdawg (Ken Ramsey) - Tropical Plants & More
[url=www.tropicalplantsandmore.com]www.tropicalplantsandmore.com[/url]
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Name: Christine
Saugerties, NY zone 5a
Charter ATP Member Hostas Container Gardener Hummingbirder Cat Lover Birds
Region: New York Lover of wildlife (Black bear badge) Dog Lover Tropicals
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Christine
Mar 6, 2016 9:15 AM CST
I have never seen such a beautiful coleus garden, I hope you dont loose any. Welcome to the forum
[Last edited by Christine - Mar 6, 2016 9:16 AM (+)]
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Name: Karen
NM , AZ (Zone 7b)
Region: New Mexico Region: Arizona Greenhouse Cactus and Succulents Adeniums Garden Art
Plumerias Hibiscus Houseplants Plant Lover: Loves 'em all! Dog Lover Cat Lover
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plantmanager
Mar 6, 2016 10:48 AM CST
Christine said:I have never seen such a beautiful coleus garden, I hope you dont loose any. Welcome to the forum

I agree Welcome!

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Name: Elaine
South Sarasota, Florida (Zone 9b)
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dyzzypyxxy
Mar 6, 2016 11:27 AM CST
Hi Karen and Welcome to ATP, that sure is a beautiful display of Coleus you've got going. Housekeeping is always the first line of defense for fungus, if you can keep removing every leaf you see infected, as quickly as possible, that will slow the spread, at least. (don't compost them, put in a plastic bag and throw away in the trash)

We've always used a mild baking soda solution to prevent the spread of mildew-type diseases. It works but must be sprayed often since the baking soda is very soluble and if you use sprinklers, it will be rinsed off each time you water, as well as whenever it rains. It works by altering the pH on the leaf surface making it inhospitable to the fungus.

That being said, I also grow orchids outdoors in Florida where we have every fungus known to man floating around in the air. I've "fought the good fight" for 5 years now, to try to use only mild, organic means like Neem Oil, but recently gave up and bought an excellent fungicide that prevents a wide range of fungal attacks. The active ingredient is Thiophanate methyl, the brand I got is Southern Ag's Thiomyl and it is a generic (less than half the price) than the widely used Cleary's 3336 and available on Amazon. It's a systemic so only needs to be used every 6 weeks or so and is rated for use on fruit trees, so the most non-toxic one I could find.

I'm sure you have excellent watering habits, but it's worth saying that watering first thing in the morning is another strong preventative measure for fungus - the leaves dry off during the day and stay dry at night. Never, ever water at night so moisture sits on the leaves through the cool, dark hours. It's an open invitation.
Elaine

"Success is stumbling from failure to failure with no loss of enthusiasm." โ€“Winston Churchill
Name: Sue
Ontario, Canada (Zone 4a)
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sooby
Mar 6, 2016 11:38 AM CST
Tiffany, I found that link too and I know what you mean about the ad! The article gives some specific fungicide suggestions based on research trials for this particular downy mildew:

"The most effective active ingredients in research trials conducted in New York and Michigan over the years have been mefenoxam (Subdue MAXX as a drench at 1 fl oz/100 gal), dimethomorph (Stature at the high labeled rate of 12.8 oz/100 gal), fenamidone (FenStop at 14 fl oz/100 gal), ametoctradin + dimethomorph (Orvego at 14 fl oz/100 gal), boscalid + pyraclostrobin (Pageant at 18 oz/100 gal), azoxystrobin (Heritage at 4 oz/100 gal) and fluopicolide (Adorn 4SC at 2 fl oz/100 gal), as well as mancozeb (Dithane at 1 lb/100 gal). Used preventively, these materials have effectively suppressed or eliminated symptoms and sporulation of the downy mildew."
Name: Arlene
Southold, Long Island, NY (Zone 7a)
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pirl
Mar 6, 2016 8:17 PM CST
Welcome to ATP, Karen.

Your gardens are breathtaking!

KarenKees
Mar 7, 2016 12:44 PM CST
Thank you every one for all your nice comments and useful suggestions. I'm going to try Neem Oil first. But, this nasty mildew is so bad and invasive that I think we will have to develop a mildew resistant strain of coleus. Your thoughtfulness and encouragement is much appreciated.
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