Southern Blight

Unfortunately, my suspicion of Southern Blight on my beans and tomatoes was confirmed by the county extension office.  Here is what they said.
 

Diagnosis: Southern Blight, Sclerotium rolfsii 


Recommendation: Nice images! May use them in talks if that is OK. Pretty clearly Sclerotium in the images. This problem has been very common lately due to hot, humid weather. While many plants can be infected, the fungus seems to prefer beans, tomatoes, and peppers. The problem with raised beds is that they tend to be used constantly often leading to more soil pathogens. The soil also tends to get mixed and will distribute the pathogens more than in natural soils. Not sure what to say about reusing the soil. A couple of plants with this disease is normal since the fungus is in most soils. If the problem is widespread and many plants are dying then the soil may be heavily contaminated, although may be ok if the beds are only used for cool season crops such as greens. Another problem with reusing soil in raised beds is that the fungus will get mixed throughout the soil profile instead of staying in certain areas. Excess water and constantly wet soils will increase disease. Allow the soil to dry out completely before watering. Water deeply but less frequently. Keep the water away from the crown area if possible. A better rotation plan should be used where beds with tomatoes, peppers and beans this year are not used in the same beds for the next couple of years. Remove and discard diseased plants. Do not compost.

The pictures of the tomatoes just show wilted plants and there is no indication on the pictures that it is actually Southern Blight.  So I may ask that those plant samples be sent to an actual lab for testing.  The picture of the bean was good and here is a copy of the plant and the stem where is goes into the soil.  See white stuff growing around the stem.  That was what they used to identify this disease.  The same white stuff was growing around one of the three tomatoes that were also affected.





The only redemming aspect about this whole mess is that I had planned on replacing the exact beds that have been affected by the disease anyway.  But I had planned on saving the soil and reusing it.  Now, I think I may just toss it.  My research on the internet shows this type of Blight is bad stuff.  It is soil borne and stays in the soil for years.  I do rotate my tomatoes every year so that is not a problem.  I have been planting beans in this same spot for 3 years in a row due to the trellis set up.  

Have you thought about solarizing the soil in your bed? Will solarizing kill the southern blight fungus?

I have never heard of this before, so I looked it up. Southern Blight is specifically mentioned to be cured by this. Here is the link:

http://ipm.ucanr.edu/PMG/PESTNOTES/pn74145.html

in case you were wondering or if somebody wants a quick explanation. Thank you John for recommending this, I learned something new!

johnmcc wrote:Have you thought about solarizing the soil in your bed? Will solarizing kill the southern blight fungus?

Yes I have thought about solarizing the soil.  The affected soil is in one 4 x 4 bed and 3 beds that are 2 x 2.  The U of Fl says you can reduce the number of disease organisms if the temp remains high enough.  So I have considered it.  I am going to replace the bed frames this fall/winter anyway due to decay.  So the only question is whether to reuse the soil after solarization or just start over with new soil.  This is Mels Mix which is now 5 years old so I would already be reconditioning it some anyway.  We shall see.

Thanks for that information yolos.  I'm so sorry about what happened.  

In my garden beds, after about 3 years, despite the addition of compost, the mid is pretty spent and I dig out the mix and toss it onto my perennial flower beds.

camprn wrote:In my garden beds, after about 3 years, despite the addition of compost, the mid is pretty spent and I dig out the mix and toss it onto my perennial flower beds.

Thanks Camprn, that is kind of what I was thinking.  Except I am not sure I want to spread the disease around.  I think I remember reading that there are 500 plants that can act as a host for the disease.  So I may just dump it way out in the woods behind my house.

yolos wrote:

johnmcc wrote:Have you thought about solarizing the soil in your bed? Will solarizing kill the southern blight fungus?

Yes I have thought about solarizing the soil.  The affected soil is in one 4 x 4 bed and 3 beds that are 2 x 2.  The U of Fl says you can reduce the number of disease organisms if the temp remains high enough.  So I have considered it.  I am going to replace the bed frames this fall/winter anyway due to decay.  So the only question is whether to reuse the soil after solarization or just start over with new soil.  This is Mels Mix which is now 5 years old so I would already be reconditioning it some anyway.  We shall see.

How old are the beds? What kind of wood did you build them with? 

I built my raised bed out of cedar. I've wondered how long it will last. I thought about using a composite material in my next bed but the stuff is very expensive.

johnmcc wrote:

yolos wrote:

johnmcc wrote:Have you thought about solarizing the soil in your bed? Will solarizing kill the southern blight fungus?

Yes I have thought about solarizing the soil.  The affected soil is in one 4 x 4 bed and 3 beds that are 2 x 2.  The U of Fl says you can reduce the number of disease organisms if the temp remains high enough.  So I have considered it.  I am going to replace the bed frames this fall/winter anyway due to decay.  So the only question is whether to reuse the soil after solarization or just start over with new soil.  This is Mels Mix which is now 5 years old so I would already be reconditioning it some anyway.  We shall see.

How old are the beds? What kind of wood did you build them with? 

I built my raised bed out of cedar. I've wondered how long it will last. I thought about using a composite material in my next bed but the stuff is very expensive.

The frames were made from 2" by 10" pine boards.  I treated them with raw linseed oil.  So far, they are 5 years old.  I think they could limp along for at least one or two more years.  But, roots from the nearby oak and dogwood trees have invaded my garden.  So I am starting to raise all my beds at least 12 inches off the ground.  So these few beds have to be reworked anyway.  Yea, I have considered composite materials also but so far I just can't see growing in composite material, just seems unnatural.

Yolos, what about cement? That's what we're going to go to once these rot...

AtlantaMarie wrote:Yolos, what about cement?  That's what we're going to go to once these rot...

Yep, I have seriously thought of cement.  Would you mix it yourself or get a cement truck to deliver it.  I have also thought of concrete blocks for the base.  Then I would need a bottom to the top that will sit on the cement block or concrete lower box.

Those pictures look like my cucumber vines and tomatoes and  beans.  One planting of beans  and all the tomatoes are in new MM.

Has anyone tried mustard greens as a cover crop for soil pathogens?  http://www.johnnyseeds.com/p-8964-mustard.aspx

http://wallacewow.com/products/mighty-mustard-seed

I'm not going to be planting a fall garden this year and though maybe I'd plant this in all my beds in Sept  

Kay

yolos wrote:

AtlantaMarie wrote:Yolos, what about cement?  That's what we're going to go to once these rot...

Yep, I have seriously thought of cement.  Would you mix it yourself or get a cement truck to deliver it.  I have also thought of concrete blocks for the base.  Then I would need a bottom to the top that will sit on the cement block or concrete lower box.

I used cedar to build my bed, plywood for the bottom, and cinder blocks to get my bed off the ground.

yolos wrote:

AtlantaMarie wrote:Yolos, what about cement?  That's what we're going to go to once these rot...

Yep, I have seriously thought of cement.  Would you mix it yourself or get a cement truck to deliver it.  I have also thought of concrete blocks for the base.  Then I would need a bottom to the top that will sit on the cement block or concrete lower box.

We'll do it ourselves. Mike's (DH) got a lot of experience with pouring concrete and setting up forms, etc.

I've also thought about blocks (like Brainchasm's), but don't really like the look that well. Although the extra places for herbs, etc would work...

sanderson wrote:John, nice looking bed.

Thanks!..

So sorry you have to go thru this!

I've been a member for a few yrs. now and have had most diseases and animals that affect gardens.
I had Southern Blight, and had a bad time with the county ext. folks. They did not like SFG, because it used MM. Well, it spreads very quickly, a heavy rain can put it in the isles, next heavy rain can put it in the next bed, on and on. I had it all over,  part due to me, picking veggies in 1 bed, then going to next bed, without scrubbing and changing clothes between beds,  and soil solarizeing was sort of out of question since I have too many beds. You won't know if you have it in the next bed until you try planting something that is affected like tomatoes.
I found an article about using mustard to fumigate soil. I got some cheap seed for mustard from the farm store. I planted every spot that was bare, and just sprinkled in the isles, and kept watered til it sprouted. I picked some to eat(it's good in cool weather) When it got grown, maybe the size of lettuce, I turned under as best as I could. I also planted between the mustard plants.
I cannot promise that this will def. work, but, it worked for me. I have not had S. Blight since this 1 time. Instead of just leaving some beds fallow in winter, I always plant some mustard, since it is easier than weeds to pull, and it makes good compost material!
Jo Ann

Thank you. What wonderful, helpful info, After reading, I noticed/recalled I don't have that problem where mustard, onion or garlic is planted.

little jo - does the variety of mustard make any difference ????

Yolos, I bought the cheapest one available. I didn't choose the more expensive ones that don;t get bitter in heat for I thought they maybe bred out the part that works. Mustard is usually a cool weather crop, at least down here.
Jo

littlejo wrote:Yolos, I bought the cheapest one available. I didn't choose the more expensive ones that don;t get bitter in heat for I thought they maybe bred out the part that works. Mustard is usually a cool weather crop, at least down here.
Jo

Thanks for that info little jo.  I am now trying to figure out what to do with the aisles. The water from those beds that are infected routinely leaked into the aisles.   There is hard packed clay under the pine bark mulch in the aisles.  I doubt anything will grow in the aisles.  Maybe rake off the mulch and cover with plastic to solarize or to just keep the bad guys from moving around the garden as I walk.

yolos
You  are lucky to have isles that won't grow weeds! I would grow plenty of mustard elsewhere, then put in a blender to puree. Put in Sprayer with water and spray isles. Don't do anything to cause isles to grow! Good luck!
Jo

littlejo wrote:Yolos, I bought the cheapest one available. I didn't choose the more expensive ones that don;t get bitter in heat for I thought they maybe bred out the part that works. Mustard is usually a cool weather crop, at least down here.
Jo

Glad to know it made a difference.  I happen to love mustard greens and will put some of the plants to use as food, but I also plan to plant in every bed and every bucket this fall, except for the garlic bed  For that I will use one of the new MM beds. Maybe I'll also plant it in the compost piles and around and under the tabletops.  

Kay

Because Southern Blight has infected some of my beds, I have been researching the best way to sterilize tools.  One think I did learn is about bleach.  I don't think the chlorine bleach will be the best disinfectant.  This article and others I have read say that the mixture will become impotent after a very short time.  

https://ag.umass.edu/fact-sheets/cleaning-disinfecting-greenhouse

Chlorine bleach. There are more stable products than bleach to use for disinfecting greenhouse surfaces. Chlorine bleach may be used for pots or flats, but is not recommended for application to walls, benches or flooring. When used properly, chlorine is an effective disinfectant and has been used for many years by growers. A solution of chlorine bleach and water is short-lived and the half-life (time required for 50 percent reduction in strength) of a chlorine solution is only two hours. After two hours, only one-half as much chlorine is present as was present at first. After four hours, only one-fourth is there, and so on. To ensure the effectiveness of chlorine solutions, it should be prepared fresh just before each use. The concentration normally used is one part of household bleach (5.25 percent sodium hypochlorite) to nine parts of water, giving a final strength of 0.5 percent. Chlorine is corrosive. Repeated use of chlorine solutions may be harmful to plastics or metals. Objects to be sanitized with chlorine require 30 minutes of soaking and then should be rinsed with water. Some would say that rinsing is not necessary. Bleach should be used in a well-ventilated area. It should also be noted that bleach is phytotoxic to some plants, such as poinsettias.


I mixed a solution and leave it near the garden and use it whenever I use any tools.  But now I learned that the solution will degrade very fast.  One article I read says to use it within 20 minutes.