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A reminder about Impatiens Downy Mildew

Posted by rhizo_1 7a AL (My Page) on
Sat, Feb 16, 13 at 6:04

I thought that it might be time (or past time) to remind everyone about the deadly and internationally ubiquitous disease that is wiping out plantings and baskets of Impatiens everywhere.

Downy mildew is a common disease on many kinds of plants but this strain is specific to Impatiens walleriana hybrids. The spores are spread by wind, rain, plant to plant contact, splattering of water, humans, etc. There is no cure.

It can be prevented by two measures : early and frequent chemical intervention using a variety of fungicides OR not planting Impatiens walleriana at all until we start seeing new introductions proclaiming resistance. That day is probably not far off....heavy duty research has been on going for years all over the world. This is a billionS dollar business....research dollars are not scarce.

The 'Sunpatiens' hybrids appear to be highly resistant but require more sunlight than the shade loving walleriana. New Guinea impatiens are also unaffected...but need lots of sunlight.

Many of us have discussed this problem at length in the past. We've come up with some very interesting substitutions for shady locations. This isn't a new problem, it's just more widespread.

So, be a smart consumer.


Follow-Up Postings:

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RE: A reminder about Impatiens Downy Mildew

Keeping my fingers crossed. I just got a new impatiens, and am including a pic. And I've saved a couple from last year and they're fine. I haven't seen this disease here in Houston at any nursery and all of the ones I bought last year were fine. Hopefully, it won't show up this here year, I really like impatiens.


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RE: A reminder about Impatiens Downy Mildew

  • Posted by mxk3 z5b/6 MI (My Page) on
    Sat, Feb 16, 13 at 8:45

I usually grow from seed, hope that alleviates the problem in my own yard. My neighbors aren't too big on flowers, so hopefully nothing will get carried over to my property. (shrug)


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RE: A reminder about Impatiens Downy Mildew

Mxk3, growing your own from seed doesn't protect you, unfortunately. The propagules could be blown in from miles and miles away in a storm or on the feet of a bird.

It certainly improves your chances, though. Many of the people who have posted here feel very strongly that they brought this disease home with them from the garden center.

Eahamel, your impatiens is a beauty.


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  • Posted by zenman Ottawa KS 5b (My Page) on
    Sat, Feb 16, 13 at 18:23

And I think Eahamel's impatiens is New Guinea, so it should be safe from the dreaded Downy Mildew. Incidentally, I once saw some Downy Mildew on a zinnia, and it is weird stuff.

ZM


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RE: A reminder about Impatiens Downy Mildew

Rhizo, are most nurseries aware of this disease? Because, they make most of their money selling impatients and petunias. Can it linger in the soil?


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Zenman, I'm pretty sure that the Silhouette series of Impatiens is I. Walleriana. Please correct me if I'm wrong. Anyway, I get a Downy Mildew on my zucchini sometimes, and it IS a weird disease. I've never seen any on my zinnia....powdery mildew sometimes. That's bad enough!

Ladyrose, I honestly don't know how aggresive the education program is
beyond the actual growers. I'm thinking that very little official research data filters down to the garden centers, but feel certain that the professional growers are getting plenty of information. Of course, consumers get zero info, unless they stumble into it. I think I might call my local Extension office next week, just to see how informed they are! I hope that I'm pleasantly surprised.

Downy mildew of Impatiens (Plasmopara obducens) is tricky. It's not a fungus so not easily controlled by the chemicals available to us (consumers) . It also has two stages....one exists in free water such as rain, droplets on the foliage, etc. The other stage is located within the infected plant cells. When diseased leaves fall to the ground, those spores can last in the soil for years!

Let's add more means of prevention, which I should have mentioned first......housekeeping! Remove fallen leaves and infected plants regularly. Also, avoid overhead irrigation at all costs. Plant tissues can only become infected when droplets of water are present.


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RE: A reminder about Impatiens Downy Mildew

  • Posted by zenman Ottawa KS 5b (My Page) on
    Sun, Feb 17, 13 at 13:23

Hi Dorie,

"I'm pretty sure that the Silhouette series of Impatiens is I. Walleriana."

After a lilttle googling, I'm pretty sure you are right about that. And thanks for the info that Downy Mildew is not a fungus. That stuff is weird scary. And you are very helpful in sharing your horticultural expertise. This ongoing threat of Downy Mildew against Impatiens walleriana is troublesome, and potentially dramatic.

Good save on Silhouette not being New Guinea. I don't know where I got that misconception. It is an expensive patented (Syngenta) cultivar, which would make its loss to Downy Mildew even more troubling. It's good that people like you help prevent the spread of horticultural misconceptions.

ZM


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You're so kind, Zen...I figure that we're all learning together. :-)


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Zenman, no, mine isn't a New Guinea, I've never had any luck with those. It's hard to see detail in the pic I took, sorry.

Dorie, thanks for the info about how downy mildew is spread. I just about always water from overhead, usually rain water. I'll try to remember to put the baskets in a bucket of water instead.

Has anyone tried to treat the downy mildew with milk? That's been used successfully on zucchini and other crops.


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Eahamel, downy mildew aside, putting any plants in a same bucket would be a sure way to spread any common pathogens like botrytis and pseudomonas. Would you be able to use a watering can with a small funnel-type spout you can aim between the foliage? I do that, with a milk jug for refilling in the other hand.

I'm sure "they" are trying everything to find a cure and/or develop a resistant hybrid. I've heard of milk being recommended for powdery mildew, which is an unrelated, different issue (as well as being a topical issue vs. systemic.) Such a bummer. Maybe little sterile bubbles (like the bubble boy from Seinfeld?)

I wonder if this is like when a plague ravages humans, like smallpox. The few left standing are immune. Is that possible with this kind of disease in plants?


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Purple is right...Downy mildew is not Powdery mildew.

Eahamel, the secret to watering with disease prevention in mind is to water the top of the SOIL, not through the foliage. That's pretty easy to do in containers....not so much in the garden or border.

Purple, this particular strain of Downy mildew is not new. I think that it has exploded for a lot of reasons.


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First off thanks for bringing this issue up again.

"Rhizo, are most nurseries aware of this disease?"

I'm going to say yes. Here in SW Florida (my winter retreat) I was practically lied to from a "vendor" in Home Depot. He was carefully cleaning out the bad ones three months ago. Have you ever seen that before? Nope. In the past they would flourish in the home centers.

I asked if he had heard of the disease. The reply was no, but I sensed he was well aware of it. I mean this guy was pulling trays and trays off the floor and simply replacing them with "healthy ones" I could see a wave of infected plants and some that did not show the disease...yet.

By the way these places are perfect for incubating (right word?) the disease. All plants are watered heavily daily, throw in a few cool nights and bingo, it starts up again.

My personal experience in both Florida and North Georgia shows they are affected during wet/damp cool periods. The soil issue is probably right on target as well. However the disease is almost non existent/stops when warmer/hotter weather appears. I noticed that last summer in North Georgia. It was also a wetter summer than usual. I'm going to experiment this year by waiting until mid June (average last frost April 20) to plant because I really miss those buggers. If they make it into mid September I’ll be pleased.

Another thing. While the big growers may not seem to "be aware" I look around at dozens of well manicured golf course communities here in SW Florida that probably have their own nurseries and none have touched Impatiens this season. Instead Begonias are mostly being used.

I’m also thinking Impatiens may not be as affected in drier climates where humidity levels are low?


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I spent many years in the wall to wall golf course area of coastal S Carolina and never knew one to have their own large production greenhouses. It wouldn't be cost effective. Anyway, you are so right about the kinds of temperatures to be aware of. Humidity is not so much of a problem as free water, but could certainly be an issue.

The disease is alive and well in any location that isn't given an opportunity to dry in between irrigation cycles, even in very arid sites. That tried and true rule of not watering at night or late afternoon is a good one to stick to.

Golf or resort communities are limited as to when they can do their watering. Those pesky property owners or club members want their walking and bike paths dry in the early morning. And if you don't think that there would be some major squawking from the golfer....holy moly. The greenskeepers are on the job pre-dawn, and everything has to be dry by then for the early mowing. That means that the irrigation system must be programmed to run at night.

Now, here's the thing about the golf course industry....it is supported by billions of research, education, and outreach dollars. You just wouldn't believe the quality and quantity of information available to superindents. Those folks will know ALL about this or any other pest or disease trend.

I've never seen anything like it in other 'green ' industries.


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I'm still not clear, if there's a clear answer, is it possible for individual plants to be immune?

"I've never seen anything like it in other 'green ' industries. " Rhizo, by this, did you mean the golf course superintendent education, or this disease?


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Rhizo:

You'd be surprised with clubs that want $150K as a membership fee. I'm only talking about main drive throughs and around the clubhouse. Some here actually maintain the center mediums of the main highway along the property.

Good points, but how do you clean up morning dew?

purple: Both, they know what's going on. Big, big money in maintaining some of these golf courses with the education, and continued learning at the top levels.

Individual? It's roulette.


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  • Posted by gerris2 Zone 7a Delaware (My Page) on
    Wed, Feb 20, 13 at 17:48

There are reports of induced disease resistance in certain plants which are grown in potting mix which has a certain percentage of vermicompost or worm casts. Maybe it's worth giving worm poop a try this summer in the plant containers.


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Purple, I meant the bombarding of information, research data, new products, free seminars, etc. that seems to be available to golf course employees....especially if they belong to one of the associations pertinent to the industry. There's soooo much money in the golf industries.

Purple, yes to the inherent resistance to individual plants. I suspect that some acreage is devoted to that kind of research. Plant selection for special qualities is an on going technique in the development of new cultivars of all kinds of plants. But most of the work in this instance is likely to weigh heavily on the side of breeding. We want an impatiens with the colors, shade tolerance, and bloom period longevity of our favorites AND superior disease resistance, too. We ain't askin ' for much, are we?

Gamountains, I'd be surprised if high end clubs produced their own annual stock. I've worked for and consulted for quite a few of those places from Myrtle Beach to Hilton Head. It's all about contract growers.

The plant orders are placed months (even a year) in advance to these big growers. The deliveries can be staggered to accomodate the needs of the club. Logistically, the growing and staging of hundreds of thousands of plants is NOT something that can be done in-house. Let the burden of production, delivery, and quality be on the contract growers. Win win.

Over the years, I've coerced a couple of such properties to build a commercial size production greenhouse for me. I was able to grow some out of the ordinary plant material that our contractors didn't want to mess with at the time. That was great fun! But I sure did have to fight for the real estate.

Gerris, anything that helps plants to be healthy is bound to promote natural resistance. We need to foster a healthy soil and follow BMPs (best management practices) ...if we do that, we'd probably see fewer incidences of infection. With vermicompost, though, a little goes a long ways in container. You don't want to add a lot of something that will turn mucky in a few weeks.


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  • Posted by gerris2 Zone 7a Delaware (My Page) on
    Thu, Feb 21, 13 at 4:31

Here's a link to a research article with good references at bottom of abstract page.

Here is a link that might be useful: literature on disease suppression using compost tea


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Rhizo:

Makes sense. They have the dough. I though perhaps some may buy large quantities of plugs and go from there.


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  • Posted by gerris2 Zone 7a Delaware (My Page) on
    Mon, Feb 25, 13 at 13:01

Here's a related article in which the researcher was able to control to a certain extent development of powdery mildew on balsam using aqueous extracts of vermicompost sprayed onto the plant leaves.

Here is a link that might be useful: Singh, et al 2003 Antifungal activity using aqueous extract of vermicompost vs. powdery mildew of balsam


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  • Posted by zenman Ottawa KS 5b (My Page) on
    Mon, Feb 25, 13 at 15:52

Powdery mildew on balsam is a far cry from Downy mildew on Impatiens walleriana hybrids. And since just plain water is a control for Powdery mildew, it isn't too surprising that an aqueous extract of vermicompost might have an effect, since the water, and not the earthworm byproduct, would be the active ingredient.


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  • Posted by gerris2 Zone 7a Delaware (My Page) on
    Mon, Feb 25, 13 at 17:47

Are you a plant pathologist?


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RE: A reminder about Impatiens Downy Mildew

One doesn't need to be a plant pathologist to be acquainted with basic fundamentals.

You clearly have some interesting information to offer. May I suggest that you would have a wider audience if you started a brand new thread in the Garden Clinic forum? The topic of this thread is, after all, about Downy Mildew of Impatiens.

This is not new information by any means...it might be interesting for you to post in the Organic Gardening forum as a reminder.


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  • Posted by gerris2 Zone 7a Delaware (My Page) on
    Mon, Feb 25, 13 at 20:15

I was merely trying to learn from someone who was knowledgeable. Good luck folks.


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Gerris, you didn't make your intent clear at all...all I was doing was trying to give you the best opportunity possible to share your ideas. Absolutely no intent on my part or our parts to do anything but be helpful.

I don't know that there are any plant pathologists, entomologists, soil scientists, plant physiologists, etc. who frequent the forums, but you'll find an abundance of knowledgeable and experienced people.


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As someone who works in the young plant industry for an EXTREMELY large grower, I can say that any any greenhouse that grows and sells plants as a profession must be living under a rock to not be aware of the Downy Mildew epidemic. Anyone who thinks that they are "immune" has unrealistic expectations. MILLIONS of dollars have been and continue to be poured into this problem both in trying to discover treatments for prevention as well as development of resistant strains of wallerana genetics. Trust me, the professional breeders of these plants have already tried all of the "home remedies" with no success. If you insist on purchasing impatiens, plan on losing them. It will make absolutely no difference if you start them yourself from seed or cuttings, or if you buy plants from a Big Box or little garden center. Rhizo has presented some EXCELLENT information on how it is spread, and it doesn't matter how ideal your conditions are, how good of a grower you are, you stand an extremely good chance of losing your plants.


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I always plant mine from seed and last year they were a disaster anyway. Avoiding them this year.


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I still have most of mine from last year. No problems, but keeping those digits crossed.


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This has been around since 2003 (in the UK) and nurseries are certainly fully aware - the more responsible growers have stopped growing any I.walleriana at all. The I,hawkeri (New Guinea hybrid) has some tolerance and supposedly, the Sakata Seed Co has bred Sunpatiens, another hybrid which is reportedly immune (as well as being appropriate for sunny situations).
Anyone selling I.walleriana is definitely pulling a sharpie since this is not just a little localised nuisance but has had a devastating impact on many nurseries who have, for years, relied on this super-easy, fast growing, cheap and colourful bedding plant - Bizzie Lizzies, as we call them in the UK, were always the top selling and absolutely ubiquitous bedding plant, for indoors and outdoors.


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The 'Sunpatiens' hybrids appear to be highly resistant but require more sunlight than the shade loving walleriana.

I was *just* about to post a question re the amount of shade under which 'Sunpatiens' can thrive i.e. flower. I was hoping it would be comparable to the walleriana but it seems not...oh darn.


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Goblugal (or other experts on Sunpatients),
What is your opinion about the Sunpatiens?
I was just getting ready to pick up a 6 pac of Orange Sunpatients at Lowes. But will not waste my $8.95 if you give a thumbs down.
Thanks


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Huge thumbs up for Sunpatiens from my growing climate. Florida performance is supposed to be excellent, and they have not exhibited any traces of Downy Mildew infection - probably because of their New Guinea parentage


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Excellent! Thanks goblugal.
Don't need more plants. I just thinned 50+ petunia seedlings, many blacked eyed susan seedlings and tons of salvia seedlings.
But I will make room for these.
Thanks,
Bob


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OK...it's obviously been a long time since I purchased a pack of annuals...$8.95!!!? Yikes!

Robert's been coming home with a tray of a dozen 4" pots of Angelonia for the last couple of years. Now I know why he's not been telling me how much they cost!


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Just got home. They were 6 plants for $7.98. The Waves came in the same pac/price.
I never pay full price for any plant, but I spent so darn much for seeds this year that I thought I would blow the rest of the budget on these. Hopefully the only plants I will buy this season. Won't tell you how much your 4" pots are. :-)
I am a push over for fertilizer bargains. Embrassed to tell you how many types I have (each has it's purpose, I rationalize.) So bought a 30lb bag of all organic fertilizer for $7.99 marked down from $19.99.
Jungle Grow. Sold as a lawn fertilizer. But since organics are slow to break down versus Scott's Turfbuilder, people probably thought it didn't work. Poor repeat sales; now a good markdown.
Both at Lowe's.


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Rhizo, you can still get flats of seed propagated annuals fairly cheap, but the input costs of the vegetative varieties (like Sunpatiens and Angelonia) is much higher, not to mention that the cost of producing them has gone up for the greenhouses.


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globlugal wrote:

Huge thumbs up for Sunpatiens from my growing climate. Florida performance is supposed to be excellent.

I don't want to wear out my welcome but does anyone here have experience with "Sunpatiens" in lots of shade?


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Roue21,
I am wondering the same thing. I read a post somewhere where someone was pretty upset about them not taking as much sun as they claim. (Could have been the Sunpatients homepage).
They were upset about (what's his name..Jimmy?) who does all the hot weather trials in Dallas, who just raved and raved about their hot weather performance. That person said his irrigation systems are so over the top that of course they performed.That's one reason I bought the 6 pac. I will place them in 3 different light senarios.
If I can hit on the perfect location in my micro gardens, then I will buy next year.
Others in our forum would know the answer to your question; I should
know in the fall :-)


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Bugbite - you are talking about Jimmy Turner, who is the trial Director at the Dallas Arboretum. And his "irrigation systems" aren't over the top. Are they good? Absolutely. You can't grow in Dallas without some type of system!


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Goblugal,
In the link are some comments.
For a few years I have been reading the trial results from several trials sites including Jimmy Turner's. Last year I thought I would fly to Dallas to visit the trials but it seemed to be closed to non-commerical people. Is that true? I realize I should just call them, but thought you might know.
(My favorite is Allen Owings.)
Thanks,
Bob

Here is a link that might be useful: Some Sunpatient comments.


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What advice can y'all offer IF a garden center is offering impatiens IF the downy mildew is known to be in your area. I'm in Metro Atlanta.

It's way early here for planting annuals, but I suspect they are already in stock. Planning throwing a hissy fit anywhere I see them for sale. Suggestions for who to talk with at the retailer to get results, that is, pulling them from stock will be welcome.


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I would be so very impressed with any garden centre which makes the conscious decision to not carry the walleriana impatiens.

Having said that I find it very unlikely that will be the case.

What you might do is to find a one page detailed description of this 'disease' on the internet and have it with you when out and about this spring and summer so that you can give a copy of it to the manager (although I do find it hard to believe that 'they' dont know about this problem).

Or you might even be proactive and make contact with your favourite nurseries right now and ask about their plans with respect to stocking this plant.

This post was edited by rouge21 on Sun, Mar 24, 13 at 11:26


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Hmmmm, It might be worthwhile talking to the store owner or manager. Just to let them know that this disease is active around the country, and what to look for...how to answer questions about it...what to do when customers complain about their plants collapsing at home, etc. The Big Box stores can't do a thing about it....they pretty much have to stock what is shipped to them. And we all know that the level of horticultural knowledge is not the best or non-existent in those places. Not criticizing, just being factual. I like rouge's idea about providing an internet fact sheet...one from a research university. Rosie, out of curiosity, I typed UGA impatiens downy mildew into Google and came up with all kinds of good hits.

Retail outlets will face many very angry consumers if they DON'T stock impatiens, please remember that. If I had my own garden center, I'd probably carry them but have an information sheet to give to each customer who buys some. At least they will be well informed, As a matter of fact, I would rather a customer buy them at my store and become educated then to huff off and buy elsewhere not knowing a thing.

Then, you can be darned tootin' that I'll make it a marketing tool for me. I'd offer a slew of other shade-friendly options to replace impatiens in baskets and the garden and plant up lots of examples and show beds. I'd provide lots of substitutes....which is important when trying to pry impatiens out of someone's hands.

My garden center (the one in my head) would be all about education. This subject would be one of the morning lecture series...I'd bribe an expert from one of the universities to help.

My brain is thinking now....I'd contact the newspaper to let me do a feature story about this disease and to show all of the different suggestions that everyone can find in MY garden center! ;-) Our local television stations also showcase business stories and I'd sure get myself and my business on the news....explaining the facts about this disease and trying to get people to try some safer options.

This post was edited by rhizo_1 on Sun, Mar 24, 13 at 11:25


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  • Posted by mxk3 z5b/6 MI (My Page) on
    Sun, Mar 24, 13 at 11:30

My sister told me she read in the gardening column of the local paper that some of the nurseries around here will not be carrying impatiens this year as they do not want their reputation ruined (because, you know - consumers blame everything on the STORE...), they will be offering other shade-loving annuals. I imagine they will have signs and sheets everywhere about why they aren't carrying impatiens and what else to grow instead. It's the independents that are doing this. Good for them!


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I'm not encouraged about what I'm reading here and on google.

rhizo, please help me understand this statement of yours: "If I had my own garden center, I'd probably carry them but have an information sheet to give to each customer who buys some".

I was heartened when my SIL said his company would not be planting any impatiens this year and not in the foreseeable future. They normally would be planting hundreds of flats. And I feel it is not right for anyone to until the cause is found and a 'do-able' treatment is found. Maybe applying fungicides every two weeks, maybe more frequently, could hold it at bay.

I'm done ranting for the moment. Time to take a deep breath.And not even proofing this, just sending, possible warts and all.


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I stopped by 1 of the biggest garden centers in my area this AM.They had a whole section of impatiens.If I had seen someone working back there I might have struck up a conversation about the mildew problem.
I'm going to a garden club meeting tomorrow night where my favorite grower is giving a presentation. I can't wait to ask him about the downy mildew in impatiens & also coleus.
rose


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Bugbite - The Dallas Arboretum is open to the public. The trials are part of the Arboretum, so can be viewed.


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  • Posted by saldut 9-10 st pete, fl (My Page) on
    Tue, Mar 26, 13 at 19:32

Well, I didn't get any Impatience this spring, not worth the hassell......I had planted some red Salvia last year and they are still blooming out there, so I got some more of them, also I found that Gaillardia and Rudbeckia and other daisy types do well in that area, I got some seeds and grew them and now they are doing well out there....also Snapdragons do well there..... that bed is under a large magnolia and the tree roots are right up near the surface, so it stays 'poor', also dry, also it is partly shaded with some afternoon sun.... I'm hoping this all works out this summer when the heat and humidity hits!! goodbye Impatience plants, it's been good to know 'ya......sally


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Back from my winter retreat in Florida and I see the local Lowes is offering them and so early to boot! I did get a refund from the local store manager last year on two flats, but she did not know of the problem or was just ignoring it. Nice gal, but perhaps pressured by profit ridden upper management.

So what did they say Rose?


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The local greenhouse man addressed this to garden club. He said he has not seen this in our area & is growing them.He said no doubt the disease is coming but plant & enjoy if you wish. Don't fill your shade spaces with impatiens & wail if they succumb.
Rose,Iowa


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Iowa? Makes sense. Probably just a matter of time.


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I've seen Impatiens at every store I've shopped so far this year. That's not saying a whole lot, not many shopping options around here, but they're out there, at every store that sells plants.


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They are in every place I've been & I've been to quite a few places.
rose,Iowa


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I wonder if the way certain annuals were "domesticated" and hybridized over decades is the problem here. Like the potato, they've become highly inbred...a factor which indirectly contributed to the potato blight. There are actually genetic tests for determining the degree of heterozygosity in an organism, at least in mammalian genetics. (Amusingly enough, this is part of the '23andme' testing service. Yes, you can find out how inbred you are compared to other people) It would be interesting to compare annual hybrids with their wild-native, parent species.


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I plant hundreds of impatiens every year and first had symptoms and some dying plants in 2011. Thought it was animal damage.

Last year, my plants begain to die at an alarming rate. I went online and discovered the cause. All contracted the disease, the containers and hanging baskets last. After all that money and labor, I had to pull all out and put them in trash bags--heartbreaking.

Yes, I'm very annoyed at the large, well-known nursery that sold them last year and should not have This was not a big-box store and there was no way they did not know what was afoot.

My one clump--six plants-- of New Guinea impatiens was unaffected but they are too expensive to replace I. wallerana.

The surprise to me as a longtime gardener is that pests or disease have not struck impatiens sooner as they are so widely grown and planted. This was a disaster waiting to happen. And despite the good intentions of many, there really is no replacement for the profuse color and easy care of impatiens.


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RE: A reminder about Impatiens Downy Mildew

If you owned a store, would you be the first to NOT have them? Do you think people would be satisfied with your explanation? The mom'n'pop garden center here in town has a great selection of them, one of about 10 diff annuals you can buy there, the same as every year, about every store. "They" will sell whatever people will buy, (like the trays of Hedera helix at WM yesterday,) and many people may buy more Impatiens if they keep dying and don't bother to find out why. Sure, there are some altruistic retailers out there, but the bottom line is the bottom line, if you look at it from the other end.

The simple facts are that there's still plenty of healthy Impatiens out there, from somewhere, and people are buying them. Those who know about the mildew know they are gambling, but when you get to the end of the thought process, is there really any harm in that? Not to be too controversial, I don't have a strong opinion one way or the other, but wonder... if this one plant is the only known one susceptible to this pathogen, why not use them unless/until the germ shows up at your house? What is the benefit of NOT doing that, if any, besides the obvious financial/visual gamble? Further imagine enough people did it so that it didn't show up in any new spots - a completely ridiculous stretch of the imagination considering something spread by the blowing of the wind, and the certainty that people are going to move plants around, and that the ones for sale would likely travel through infected areas on their way to stores in non-infected areas. Anyway, then what? How long would everyone need to wait until it was safe to go back to normal?

Is there really any righteousness or "for the greater good" possible in extremely small numbers of widely scattered people not using them "just in case?" At this point I don't want to bring any new ones home since I don't like the odds of the gamble, but some potted roots I thought were dead have sprouted new foliage, and I see a few sprouts around. Who's going to buy some, love them enough to "see what happens?"


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RE: A reminder about Impatiens Downy Mildew

I have one local nursery selling it this year whom I had a lot of respect for until they claimed this years crop has been "treated at the source" before it arrived at their place. What that means is anyone's guess.

Maybe they found the solution? I'm still too confused.


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RE: A reminder about Impatiens Downy Mildew

gamtns, I read a lot about this fairly recently. The growers with a conscience were using a very intensive fungicide treatment program in their greenhouses. Maybe, just maybe, maintaining a rigorous program in a home garden will protect them. I'm not a completely organic gardener, but pretty darn close, and know I don't want to plant something I'll be a slave to. Also, since the virus is airborn, my plants could be contaminated by my neighbors.

In short, I feel sad that I won't be seeing impatiens all over the place. They are so wonderfully colorful in a shade garden. My son-in-law owns a commercial landscape company - lots of big color beds, will not be planting the first impatiens this year and probably not for several years, until plant scientists cure this. Of course, commercial companies guarantee their plantings and would incur huge expenses in replacing.

Rosie, in Sugar Hill, GA (north Atlanta metro)


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RE: A reminder about Impatiens Downy Mildew

I'll buy 2 or 3 packs of a certain red & white one I get every year. If they die they die. I won't get any more.Simple as that.Would I fill every shady spot on the place with impatiens ? No.
Rose


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RE: A reminder about Impatiens Downy Mildew

Rosiew:

Like I've said before, I think...The disease almost comes to a stop when warm, humid weather hits. I watched it very closely last year where a few batches did surprisingly well in two areas on my property. I'm gonna give the nursery a try. They did claim this years crop order was considerably less because of the problem. If they last 2-3 months I'm fine by it, but I won't buy more than a few dozen

If you get anywhere near MaCaysville, check it out. With their growing conditions (perfect) you can pick up four packs (May) that are two to three times the size of the pint containers sold at Lowes & HD for the same price.

Here is a link that might be useful: Quinns Greenhouse


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RE: A reminder about Impatiens Downy Mildew

What has been everyone's experience with Downy Mildew this year with impatiens? It's been very wet and humid this summer and I'm surprised they haven't started to decline yet here in Maine.


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RE: A reminder about Impatiens Downy Mildew

Will try to remember to check the only ones I've seen planted in my small neighborhood, potted on a porch.

We've had seemingly nonstop rain and being Georgia, of course humid.


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RE: A reminder about Impatiens Downy Mildew

I love impatients and have never had problems with mildew, in fact my one pot of them are doing wonderful, I have heard about this disease


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I plant impatiens in the same spot every year and also potted up on the deck. I was looking at my potted ones today and noticed they weren't as heathy as they were a few weeks ago. Checked the undersides of a leaf and, yes, my plants have downy mildew. I will be getting rid of all my impatiens plants tonight. So sad, they've always done so well for me.


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RE: A reminder about Impatiens Downy Mildew

I have one plant in a planter with torenia and it's doing fine....
so far!


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RE: A reminder about Impatiens Downy Mildew

Here in California known for its low humidity, the local news contained a warning that Downy Mildew has arrived. Al


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RE: A reminder about Impatiens Downy Mildew

I planted a dozen or so from six packs a few months ago in the same spots they failed last year against popular belief that the soil would be affected for years to come. No effect whatsoever. Growing just as well as previous years. This batch came from Lowes.

I suppose it's more of your mileage will always vary. Similar to the way plants in general grow. They may do miserably on one side of the house and great on the other. At this point in time time I'm not holding back next year.


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RE: A reminder about Impatiens Downy Mildew

I was in Vancouver last week and saw impatiens everywhere...not one sign of Downy Mildew. Don't know if their climate has anything to do with it, but I know I won't be buying these again for many years.


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RE: A reminder about Impatiens Downy Mildew

  • Posted by mxk3 z5b/6 MI (My Page) on
    Sun, Aug 11, 13 at 12:52

My seed-grown ones are fine so far....


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RE: A reminder about Impatiens Downy Mildew

I have them in a few spots and they are doing well like gangbusters! I'm in Portland, OR though (similar climate to vancouver as previous person mentioned). Low humidity in the summer and its been an even drier than normal spring and summer.


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RE: A reminder about Impatiens Downy Mildew

UHOh! Apparently the dreaded impatiens virus has been found in a town near me.There was a piece in the paper by a member of the garden club. My garden buddy who lives in that town had several impatiens in pots .I gave them to her. I haven't talked to her yet & am anxious to see if hers are still OK.
Rose


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RE: A reminder about Impatiens Downy Mildew

A friend in the Atlanta area told me this morning that 'all of a sudden her impatiens died'. She'd never heard about Downy Mildew. I told her to bag and dispose of everything.

I sure do miss impatiens in my back garden.

Rosie


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RE: A reminder about Impatiens Downy Mildew

This thread has surely been interesting to follow these many months. I hope that we can keep posting our observations and experiences.


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RE: A reminder about Impatiens Downy Mildew

I bagged and threw away my affected impatiens in all areas except for one row in my side yard. For some reason, I let those ones die naturally, but to my surprise, I found three plants still alive and when I checked the underside of the leaf, they were not coated in white. I still won't plant any more but it was interesting to see that a few managed to fight it off.


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RE: A reminder about Impatiens Downy Mildew

When a historical plague or flu wipes out most of a population of people, there are always a few individuals who are just somehow immune. I wonder if it is similar with plants and their diseases?

Thought I'd lost mine to this last year, but it perked up, overwintered, and has been propagated and spread to various parts of the yard and several pots. May have just gotten too dry or wet last year, IDK. My Mom has a HUGE white one bought this spring.


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RE: A reminder about Impatiens Downy Mildew

I have a gorgeous mauve impatiens that I didn't plant. It showed up in one of my container pots. I have no clue where this seed came from. The other plants have all passed away in their time and the pot is taken over by this amazingly healthy plant.

The one I DID plant in a pot with torenia is still looking good, although it's being overrun by the torenia.

Yes, plants can have natural, genetic disease resistance just like people.

It's been raining a lot up here in the New York Catskill Mountains, too.


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RE: A reminder about Impatiens Downy Mildew

I had a huge bed of impatiens that survived into October. At least until this last week, when we had a 3 day rainy spell. Now all have been infected. I suspect windblown spores from other areas and/or triggered by the change in temps.

I have a question. I know walleriana will be a no go for next year, but could I try in a future year? How many years do the spores survive? Would I be safe to try walleriana impatiens in 2-3 years? Or does that mean forever?


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RE: A reminder about Impatiens Downy Mildew

Field, researchers and plant breeders all over the world are working very hard to find or create disease resistant strains of Impatiens. The development of new cultivars takes a very long time since field testing can't be rushed.

Once the testing has been completed, it will take a long time to build up enough propagation stock that the plants can be introduced to the world's market place.

I'm sure that most of the major seed houses are hot on the track. It will be interesting to see what comes out in the future.

Keep Googling for disease resistant impatiens; I expect that we'll begin seeing some worthy of trying pretty soon.

I strongly suspect that the new Impatiens may be a hybrid and might


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RE: A reminder about Impatiens Downy Mildew

If the "new" Impatiens are covered by a Plant Patent and associated reproduction restraints, they may be too expensive to replace the current seed-grown varieties. If you have a relatively large area to plant, it can be very expensive to fill that with grower-grown plants. I will be very surprised if truly disease resistant Impatiens become available in seed packets.

I think a systemic fungicide might be a better solution. Has anyone tried the currently available systemic fungicides on existing strains of Impatiens? I realize that isn't an acceptable solution for organic gardeners, but not everyone is one.

ZM


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