Damping off in green beans

Asked June 29, 2017, 3:25 PM EDT

I am a resident of Cass County and am hoping that you can help me with a problem I have had for the last several years. I am at my wit’s end with the green beans in my garden. I never had any problem with them at all until the last 3-4 years. But now I am having a problem with what I would call “damping off.” The seedlings sprout and grow nicely until they are about 6-8 inches tall or even taller. Then they rot at the base and fall over. From what I have read, there must be a fungus in our soil . . . this affects only green beans. It is so disappointing! I have tried moving the green beans around in the garden, not planting in the same part of the garden each year. This is a fairly large garden (for us), so we can do that. (maybe 1500 square feet). I’ve also tried planting different varieties . . . Blue Lake was the one we always planted, but this year we tried Contender, with the same sad result.

Again this year I have young plants just branching out to preflower stage, and they are dying. I would like to replant, but I am sure the same thing will happen over again. Please help! Can I treat the soil with something before I plant? And is the fungicide that you may suggest available to a home gardener like me?

Cass County Michigan green beans vegetable diseases vegetable gardening

3 Responses

Hello,

Your problem could be one of the root rots that affect beans. Damping off is a related fungi and most commonly occurs from seed planting to seedling stage, and less often - but not impossible- at several weeks later. All of these diseases are managed by cultural practices and using seed pre-treated with a fungicide.

I will give you some detailed Extension information on managing damping off/rot in case you haven't gone through it, yet: You can compare the three common root rot symptoms to what you see-- here is a link, with pictures that you can magnify to get a close look---

http://www.extension.umn.edu/garden/yard-garden/vegetables/edible-bean-disease-and-disorder-identifi...

You mention you have rotated your crops. If you have one of the other crops that also fosters diseases of beans, perhaps that could be why your rotation didn't help? Rotation is more effective the farther apart you can move plantings.

These links have details on managing damping off/rots, and more pictures to compare. Some are for commercial growers but contain practices that may help you---

http://www.oardc.ohio-state.edu/sallymiller/Extension/factsheets/Damping%20off%20beans.pdf

http://ipm.ucanr.edu/PMG/PESTNOTES/pn74132.html#MANAGEMENT

https://ag.tennessee.edu/EPP/Extension%20Publications/SP277-O%20Plant%20Diseases%20Root%20Rots%20and...

Since this is beginning again in your garden, I recommend submitting samples to MSU Pestid lab for exact diagnosis. There is a fee, usually 10-20 dollars. Their website has the instructions, sample submission form and mailing address.

If you decide this is something you will do, dig 2-3 plants with roots the day you will mail them, retaining some soil around the roots. Soil should be moist but not dripping. (they need enough roots and soil to make a diagnosis). Bag the root ball and tie it closed so that soil doesn't touch the leaves. Package an extra cup of soil from the planting hole in a separate bag. Mail them early in the week so they do not sit in the mailroom over a weekend. Choose a plant that is just starting to show disease, as well as a sample that is further along. If you have any questions on this process you can consult the lab directly --- 517-355-4536. Here is the site---

https://pestid.msu.edu


I would replant beans now, as the conditions for rot and damping off are reduced when the soil is warm. Best bet would be to move your planting to rows that haven't had any of the 'problem' crops for 3 years, if possible. Follow the suggestions in the articles, above- hill up soil for good drainage-shallow planting- use treated seed.

Captan is a fungicide available to home gardeners and It is labeled for managing damping off; and is one of the products commercial seed companies use to pre-treat seeds. Please follow all directions and precautions when using chemicals. Here is an article which includes how to pre-treat seed with and without chemicals---

http://swfrec.ifas.ufl.edu/docs/pdf/veg-hort/transplant/trans_ds2.pdf

I hope this has been some help. If you submit lab samples, the lab report should suggest a fungicide if one is available for the pathogen involved. Thank you for using our service.



Thank you for your speedy response. I had actually read some of the articles you cited already, but I also had searched for home remedies + root rot / damping off. Some posts mentioned sprinkling cinnamon on top of the soil. Do you know anything about that? Could I mix it into the soil?

Also, I have a fungicide here called Maneb. Would that be of any help? Should I drench the soil before planting? Or mist the seedlings with it? I don't have Captan, but I will look for it as well to see what it says to do.

I intend to replant soon . . . will try a new part of the garden as far away as I can from the current crop.

Hello again,

I can find no scientific research on using cinnamon in the garden for controlling damping off. I did find a reference in an article discussing horticultural oils used to control insects-

"The food grade plant extract oils (rosemary, thyme, clove, cinnamon, etc.) function as antifeedants, repellents, or neurotoxins and thus affect pests differently than the traditional petroleum or plant/seed-based horticultural oils discussed here."

Since cinnamon is ground bark of a specific tree, I don' t think it would harm the beans. You may want to experiment with 10-12 plants.

Some Maneb formulations can be used on beans but, I couldn't find any listing that states it controls rots or damping off, only for controlling anthracnose and rusts.

If the label on your Maneb lists it for green beans you may use it as directed on the label.


Treating soil is a more expensive way to go, since the quantity of chemical needed to treat acres can be cost prohibitive. This is why pre-treating seed is recommended. After some more 'digging' I found references that list PCNB fungicide:

http://www.aces.edu/pubs/docs/I/IPM-1306/IPM-1306.pdf

http://www.lsuagcenter.com/NR/rdonlyres/C5AFCD25-0663-4BBA-961E-64EB0821C1BB/46974/pub3050DiseaseMgm...


You see the first chart lists PCNB for control of Rhizoctonia, but not the other fungi that cause damping off. As you can see, the use of a chemical isn't an easy decision.

Another resource I just discovered from Wisconsin extension lists streptomyces lydicus for control of damping off, and more, in vegetables and other plants. Extension does not recommend brands but I will give you two examples ( this is not an endorsement of these products) that contain this ingredient- Actinovate and Actino-Iron. I don't know how effective this product is.


In summary, you have several things now to try and manage this tough problem: one of the pre-treatments for your seed ( page 2 "Seed Treatments" in http://swfrec.ifas.ufl.edu/docs/pdf/veg-hort/transplant/trans_ds2.pdf), or use seed already treated; PCNB or an actinovate-type product; improved drainage; planting seed 1 inch deep; crop rotation.


I hope you get some beans this year- and that these techniques start working for you!