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Mar 5, 2016 6:05 PM CST
Thread OP

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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Mar 5, 2016 6:07 PM CST
Name: Karen
New Mexico (Zone 8a)
Region: New Mexico Region: Arizona Region: Ukraine Cactus and Succulents Plant Identifier Plays in the sandbox
Greenhouse Bromeliad Adeniums Morning Glories Avid Green Pages Reviewer Brugmansias
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.
Handcrafted Coastal Inspired Art SeaMosaics!
Mar 5, 2016 6:08 PM CST
Name: Jennifer
48036 MI (Zone 6b)
Cottage Gardener Houseplants Spiders! Heucheras Frogs and Toads Dahlias
Hummingbirder Sedums Winter Sowing Peonies Region: Michigan Celebrating Gardening: 2015
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 Icon for preview
Mar 6, 2016 7:54 AM CST
Name: Caroline Scott
Calgary (Zone 4a)
Bulbs Winter Sowing Plant Lover: Loves 'em all! Peonies Lilies Charter ATP Member
Region: Canadian Enjoys or suffers cold winters Million Pollinator Garden Challenge Garden Ideas: Master Level
I wonder if a spray with dilute peroxide would help?
Just an idea---I have no experience with it.
Mar 6, 2016 7:58 AM CST
Name: Tiffany purpleinopp
Opp, AL @--`--,----- ๐ŸŒน (Zone 8b)
Region: United States of America Houseplants Overwinters Tender Plants Indoors Garden Sages Plant Identifier Garden Ideas: Level 2
Organic Gardener Composter Miniature Gardening Million Pollinator Garden Challenge Tender Perennials Butterflies
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: (worth waiting for the ad, IMVHO)

Some other colorful plants you might like...
Beefsteak Plant (Perilla 'Magilla')
Perilla 'Magellanica'
Iresine herbstii (a red plant)
Bloodleaf (Iresine diffusa f. 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 Heart (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)
Joseph's Coat (Alternanthera ficoidea 'Partytime')
Calico Plant (Alternanthera dentata 'Purple Knight')
Joseph's Coat (Alternanthera littoralis)
Joseph's Coat (Alternanthera ficoidea 'Red Threads')
Alternanthera ficoidea 'Snowball'
(and many others in the plant database in search for Alternanthera.)
Hawaiian Snowbush (Breynia disticha)
Euphorbia tithymaloides (dramatic pink highlights)
Variegated Devil's Backbone (Euphorbia tithymaloides 'Variegata')
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 (Coleus 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)
The golden rule: Do to others only that which you would have done to you.
๐Ÿ‘€๐Ÿ˜๐Ÿ˜‚ - SMILE! -โ˜บ๐Ÿ˜Žโ˜ปโ˜ฎ๐Ÿ‘ŒโœŒโˆžโ˜ฏ
The only way to succeed is to try!
The best time to plant a tree is 20 years ago. The 2nd best time is now. (-Unknown)
๐Ÿ‘’๐ŸŽ„๐Ÿ‘ฃ๐Ÿก๐Ÿƒ๐Ÿ‚๐ŸŒพ๐ŸŒฟ๐Ÿโฆโง๐Ÿ๐Ÿ‚๐ŸŒฝโ€โ˜€ โ˜•๐Ÿ‘“๐Ÿ
Try to be more valuable than a bad example.
Mar 6, 2016 8:19 AM CST
Name: Ken Ramsey
Vero Beach, FL (Zone 10a)
Bromeliad Vegetable Grower Region: United States of America Tropicals Plumerias Orchids
Region: Mississippi Master Gardener: Mississippi Hummingbirder Cat Lover Composter Seller of Garden Stuff
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 (Dr. Kenneth Ramsey)

The reason it's so hard to lose weight when you get up in age is because your body and your fat have become good friends.
Mar 6, 2016 9:15 AM CST
Name: Christine
NY zone 5a
Deer Charter ATP Member Region: United States of America Lover of wildlife (Black bear badge) Tropicals Region: New York
Hummingbirder Hostas Dog Lover Container Gardener Cat Lover Birds
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 Icon for preview
Mar 6, 2016 10:48 AM CST
Name: Karen
New Mexico (Zone 8a)
Region: New Mexico Region: Arizona Region: Ukraine Cactus and Succulents Plant Identifier Plays in the sandbox
Greenhouse Bromeliad Adeniums Morning Glories Avid Green Pages Reviewer Brugmansias
Christine said:I have never seen such a beautiful coleus garden, I hope you dont loose any. Welcome to the forum

I agree Welcome!
Handcrafted Coastal Inspired Art SeaMosaics!
Mar 6, 2016 11:27 AM CST
Name: Elaine
Sarasota, Fl
The one constant in life is change
Amaryllis Tropicals Multi-Region Gardener Orchids Master Gardener: Florida Irises
Herbs Region: Florida Vegetable Grower Daylilies Birds Cat Lover
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.

"Success is stumbling from failure to failure with no loss of enthusiasm." โ€“Winston Churchill
Mar 6, 2016 11:38 AM CST
Name: Sue
Ontario, Canada (Zone 4b)
Annuals Native Plants and Wildflowers Keeps Horses Dog Lover Daylilies Region: Canadian
Butterflies Birds Enjoys or suffers cold winters Garden Sages Plant Identifier
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."
Mar 6, 2016 8:17 PM CST
Name: Arlene
Southold, Long Island, NY (Zone 7a)
Region: Ukraine Dahlias I was one of the first 300 contributors to the plant database! Houseplants Tomato Heads Garden Ideas: Level 1
Plant Identifier Photo Contest Winner: 2014 Million Pollinator Garden Challenge Celebrating Gardening: 2015
Welcome to ATP, Karen.

Your gardens are breathtaking!
Avatar for KarenKees
Mar 7, 2016 12:44 PM CST
Thread OP

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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