Treating leaf anthracnose

bkay2000(8a TX)June 18, 2012

I received the diagnosis from A&M of the disease bothering my Blue Angel. It's leaf anthracnose (Colletotrichum). Apparently, it's a common pathogen in farm land and in some types of trees I don't have. I have no idea where I got it or how. It's spread by watering or by rain.

They suggest removing all diseased leaves and spraying with fungicides (the report is in photos below). If you were removing diseased leaves, would you cut them, tear them or do you suggest another way to remove the leaves?

I'm debating throwing away the Blue Angel and a couple of others that show sumptoms. I've had problems with BA almost since I've had it and also on Radiant Edger. I see some limited symptoms on Guacamole and Blue Cadet, so they will have to be treated.

Does it make sense to just chunk the BA and the RE? They've been showing symptoms for a couple of years and I just didn't know what it was. Most of the others have very few or no symptoms. Is this a case of cutting my losses or am I going to have this problem forever anyway, so there's no point in getting rid of the plants?

bkay

BA starting to show symptoms in 2010

A couple of months later

also 2010

2011

2012

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irawon(5a Ottawa)

Bkay, here I go again about cornmeal and NOT corn gluten meal. It's supposed to increase the bacterial population in your soil that eats the fungus. I see these symptoms at nurseries all the time. Don't throw out your hostas as this is treatable.

    Bookmark   June 18, 2012 at 7:21PM
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bkay2000(8a TX)

So what do you do with the cornmeal?

bkay

    Bookmark   June 18, 2012 at 8:23PM
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i-like-to-grow(6)

yeah.. have you repotted with new soil? I know you only grow in pots... could also remedy the problem... I had this badly when I used shredded hardwood mulch.. the mulch would mat up and the mycellum would form.. and all my plants would get anthracnose... I used bayer fungicide once or twice the next year in the spring and switched to pine nuggets... and now you very rarely see it on my hostas.. I feel like I bring it on sometimes with overhead watering... but its not really a big deal... throwing away your hosta would be like cutting off your foot for getting a ringworm...
John

    Bookmark   June 18, 2012 at 9:07PM
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ken_adrian Adrian MI cold Z5

how do you water???

wand or overhead???

if it were me.. i would simply grab the stalk near the bottom.. and rip it out ...

i would remove every affected leaf ... and then i would use a preventative spray on what is left ...

and then i would see how it responds...

if the problem continues ... report back ...

you know you are pushing the limit of hostadom.. down your way ... and you are now dealing with something.. many of us are not too familiar with ... i dont know if i would go to chemical lengths ... will have to mull that ...

you said: I have no idea where I got it or how.

well.. the answer .. my friend.. is blowin in the wind.. and answer is blowin in the wind ...

which leads me to another question.. how damp and musky is it at night??? what is the usual as to air movement at night ....

i think you are on the cutting edge here.. and we are going to be hard pressed.. to give you spot on advice ... i think you are going to have to become the expert in this area ... i am impressed you got the professional diagnosis.. keep up the good work

ken

    Bookmark   June 19, 2012 at 8:05AM
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bkay2000(8a TX)

Actually, we have pretty good wind until it get real hot. When that high pressure system settles over us, nothing moves, but it's dry. All the gulf moisture hits the edge of the high and slides right around us.

I talked to the county agent's office today. They said not to remove the whole leaf, just the diseased parts. He said take scissors and cut out all those spots, being careful not to cut through the spots. If so, do the 10% bleach solution followed by a rinse before making another cut. Then, apply the fungicide.

I'm still hoping for irawon to tell me about the cornmeal. There might be an organic solution there.

bkay

    Bookmark   June 19, 2012 at 6:46PM
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Charlie44(7b)

I don't know if this will help but I found it on the Dirt Doctor's web site.

DISEASE CONTROL - Use whole ground cornmeal for root and soil borne fungal diseases at 10-20 lbs. per 1,000 square feet. Cornmeal works as a disease fighter in the soil by stimulating beneficial microorganisms that feed on pathogens such as brown patch in St. Augustine, damping off in seedlings and other fungal diseases. Use cornmeal at about 2 lbs. per 100 square feet to help control any soil borne fungal diseases on both food and ornamental crops. One application may be all that is needed, but multiple applications are okay if necessary because cornmeal serves as a mild organic fertilizer and soil builder. Cornmeal needs moisture to activate. Rain won�t hurt cornmeal�s efficacy because, like all organic products, it is not water soluble. Cornmeal tea can also be used for disease control. Soak 1 cup of cornmeal in 5 gallons of water for 30 minutes to an hour, strain out the solids and spray the foliage of plants.

    Bookmark   June 19, 2012 at 7:40PM
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Babka NorCal 9b

There are all sorts of uglies that can get to those leaves.

You can scroll down to the Anthracnose part. I like the part where it says it won't kill the plant, just make it look ugly.

-Babka

Here is a link that might be useful: Hosta diseases

    Bookmark   June 19, 2012 at 7:46PM
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Steve Massachusetts Zone 5b

bkay,

Corn meal is hocus pocus. Let's see on the one hand we have the recommendations from the plant pathology clinic at Texas A&M and on the other hand we have an organic Internet Dirt Doctor.

Good grief.

You don't want to turn this into another "chemical/fungicide organic cesspool of vermin and horror."

Steve

    Bookmark   June 19, 2012 at 7:51PM
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Moccasin(z9aMobileAL)

BKay, if you are cutting edge for this, then that means I am in a heap of trouble here too. But look at it this way, we are almost to the first day of summer.

All the rain we had last week made a quagmire of my garden, and I could not walk around in it. I noticed that there was soil splashed up on every pot, so I'm supposing it was also splashed on the leaves as well. Some of the hosta, like Paradise Island for one, have signs of insect damage, perhaps slugs or perhaps the cutworms. On my shopping trip today, I stocked up on the Bug-geta (they did not have Sluggo Plus at Lowes), and the Bayer fungicide, including some for trees. What I have to deal with here is like a primordial soup, and I have to make up my mind to use some chemicals but pick carefully.

I'd be very interested in the way Irawon uses corn meal. If that is not a common product in these parts, I don't know what is.....except grits. I have just one question: self rising or plain?

BKay, I hope you keep all the information on this issue so it can be collected for a FAQ or maybe a report back to A&M about your experience. The series of photos documenting the condition of your hosta is admirable.

    Bookmark   June 19, 2012 at 8:02PM
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Moccasin(z9aMobileAL)

BKAy, I was wondering if anything was posted so I googled for corn meal insecticide.

They did a project at Texas A&M--bless those Aggies!!!--and I found a link below that pretty much says it is not an effective fungicide. You might want to take a look until you hear from Irawon.

Here is a link that might be useful: Is cornmeal a fungicide?

    Bookmark   June 19, 2012 at 8:23PM
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bkay2000(8a TX)

Steve, the dirt doctor is the local "organic" guru, Howard Garrett. He is credentialed. (I think he's a landscape architect by training.) He's been a player in the local gardening scene for years and years. He hasn't always been "organic", though. Charlie knew I would know who he was talking about.

I try not to use any more chemicals than I have to. I will do everything I can to eliminate the conditions that allow this fungus to live here, which might include spreading some cornmeal. But I'm still going to spray with a fungicide and cut out all the spots on all the hosta.

bkay

    Bookmark   June 19, 2012 at 8:39PM
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bkay2000(8a TX)

Yeah, bless those aggies! You can count on them, though. (Most all the Vets in Texas are aggies, so we all love aggies, naturally.) They run a good horticulture department, too.

bkay

    Bookmark   June 19, 2012 at 8:51PM
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irawon(5a Ottawa)

Well bkay, I did a bit more research. While I was writing this reply Charlie posted.

I started using cornmeal about 2 years ago based on a research study done in the 1930's in which a bacterium by the name of actinomyces albus grown in a cornmeal medium was found to inhibit the growth of Colletotrichum lindemuthianum as well as several other fungi. It was found that it was something that the bacterium produced that was the inhibiting factor. The study involved controls. The study was conducted by Kent State University.

Basically what I did was sprinkle cornmeal around my hostas in order to increase the beneficial microbes in my soil, hoping that it would control foliar nematodes as well. The earthworms and the rain, I felt, would work the cornmeal into the soil.

I wanted to do some more research before answering your question. I came across a second paper published in 1994 regarding the views of Dr. Teruo Higa, a professor of Horticulture in Japan, and a doctor James F. Parr, a soil microbiologist at the U.S. Dept. of Agriculture in Maryland. The bottom line in the paper about inoculating your soil with specific beneficial microbes was that there were too many variables to have a consistent beneficial outcome. The paper recommended applying organic amendments (seaweed, fish meal and crushed crab shells) in order to balance the micronutrient content of soil so as to encourage a broad spectrum of beneficial microbes, including an increase in the population of antibiotic producing actinomycetes to keep the pathogens in check when environment favours them.

In the end I came away with the impression that depending on individual soil type what might work for me might not work for you. I did come away with a commitment to vary the organic material that I add to my soil in order to increase the disease suppressive flora in my soil, and to provide my hostas with the nutrients to maintain their health.

Since you grow your hostas in pots, I would would follow ILTG's advice and replace your potting soil after scrubbing your pots with the 10% disinfecting solution.

Thanks for the information about not having to discard the whole athhracnose infected leaf.

    Bookmark   June 19, 2012 at 9:00PM
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Steve Massachusetts Zone 5b

My philosophy is to use the least toxic thing that will actually work. If there is real evidence that corn meal works as a fungicide, I'm all for it. But I can't find any, and that's because it's voodoo gardening.

Steve

    Bookmark   June 19, 2012 at 9:05PM
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Charlie44(7b)

Have you ever tried it ?? Howard Garrett is a landscape architect by training, with extensive experience in landscape contracting, greenhouse growing, golf course planning and maintenance, and organic product development and has a BS in Landscape Architecture.

    Bookmark   June 19, 2012 at 9:17PM
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Steve Massachusetts Zone 5b

Linda Chalker Scott is a professor at Washington State University. She often debunks gardening myths that are perpetrated by those espousing horticultural nonsense.

"Nevertheless, we're informed that a gardening personality has "continued the study and finds cornmeal effective on most everything from turf grass to black spot on roses." This is directly refuted by Dr. Jerry Parsons, who by happy coincidence is an extension faculty specialist at Texas A&M. His informative (and hilarious) column on brown spots in lawns states "Lately there have been claims made that corn meal and a garlic extract is effective. This is absolutely false! Everyone trying to do the "environmentally friendly-to-a-fault" thing have been wasting their money. They would have been better off making corn bread and using their garlic for cooking purposes!""

Here is a link that might be useful: Cornmeal myth busted

    Bookmark   June 19, 2012 at 9:17PM
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Charlie44(7b)

I meant to say that no I haven't tried it so I don't know for sure and can't say it's voodoo gardening for that reason.

    Bookmark   June 19, 2012 at 9:26PM
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Steve Massachusetts Zone 5b

It's voodoo gardening because there is no evidence that it works! These people are trying to sell something. In this case this Howard Garrett dude is selling himself. Read the link it's nonsense.

Can't we agree to use actual science and research? This is the kind of stuff that gives the Internet a bad name among professionals.

Steve

    Bookmark   June 19, 2012 at 9:32PM
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Charlie44(7b)

I read the link and all I saw was that Marie Iannotti has been gardening for years, no mention of any formal training. Maybe cornmeal works and maybe it doesn't I can't say for sure.

    Bookmark   June 19, 2012 at 9:43PM
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Steve Massachusetts Zone 5b

When you become a Master Gardener the first thing they teach you is that you use research and evidence when presented with gardening problems or questions. Marie Iannotti should be ashamed of herself for perpetuating nonsense without any proof. Your refusal to admit that cornmeal doesn't work even when presented with incontrovertible evidence that proves this, disappoints me.

Steve

    Bookmark   June 19, 2012 at 9:51PM
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Charlie44(7b)

Steve I didn't mean for this to deteriorate this way. All I was trying to say is I have no firsthand experience using it. I don't like to say something does or doesn't work if I haven't tried it. That's for someone else and I certainly in no way meant to imply that I am a master gardener because I'm just a hobbyist.

    Bookmark   June 19, 2012 at 10:06PM
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i-like-to-grow(6)

LoL..... All this talk of cornmeal makes me wanna fry some tilapia...
Anyways... You can kill a lot of fungus with bleach...
John

    Bookmark   June 19, 2012 at 10:50PM
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irawon(5a Ottawa)

Cornmeal is NOT a fungicide. It is a FOOD. People eat it. From what I have read microbes eat it too and multiply. From Charlie's post I read that the DirtDoctor also considers cornmeal a mild fertilizer.

As I understand it some soils may lack some of the beneficial microbes for various reasons including pesticide use. Some of the microbes that may be lacking may keep certain pathogens affecting hostas in check.

A good means of introducing a wide variety of microbes to your soil is by adding a wide variety of organic fertilizers (manure, seaweed, mushroom compost etc.) to your soil. Some microbes make the nutrients in soil available to plants. Other microbes feed on fungi. There are various fungi. Some fungi are pathogens. Other fungi stimulate root growth. Not all organic fetilizers contain the same microbes. Synthetic fertilizers contain no microbes.

It is my understanding that nature provides checks and balances, which can be disrupted by environmental factors. Why do farmers rotate their crops? It allows certain used-up nutrients to be rebuilt in the soil. The same relationship exists between the soil and microbes; the nutrients which support microbal and plant life have to be replenished.

I'm not recommending cornmeal as a replacement to the chemical fungicides available when they are needed. From what I read, I believed that cornmeal promotes the growth of the beneficial microorganism that keep pathogens from infecting our hostas.

I have no problem with being corrected if I am in error in my assumptions. We all have a common interest in promoting the best growing connditions for hostas.

    Bookmark   June 19, 2012 at 10:55PM
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i-like-to-grow(6)

Howard might have stock in cornmeal lol

    Bookmark   June 19, 2012 at 11:13PM
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irawon(5a Ottawa)

"Howard might have stock in cornmeal"

John, I can't stop chuckling.

    Bookmark   June 20, 2012 at 12:46AM
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Moccasin(z9aMobileAL)

The lab in Maryland would of course be the one coming up with using crab shells--that is a very common by product in that area. Just like we have lots of it down here too.

And in Iowa and Texas and such where agricultural products of the land are common, they come up with uses for major industrial (ag. industry) by products.

And BK, one of my dear friends here in Mobile has a horticulture degree from TX A&M.

    Bookmark   June 20, 2012 at 1:54AM
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