Fungal problems, in mulch or soil

[Anthony_Toronto]

Three years ago, decided to put landscape fabric over soil, and about 5 (or 6) cubic yards of mulch on top of this. In the first year plants did fine, but had some odd and extensive fungal growth in the mulch. For the last two years, plants have had extensive fungal-type foliage difficulties; a slow progression of blight-type problems. I am rather reticent to remove 5 cubic yards of affected mulch, if that is the problem. Is there anything that I could use to treat the mulch to get at least some relief from this problem?

thanks...

[RayR]

What kind of mulch are you using?
I'm not a big fan of landscape fabric, it can keep too much moisture on the soil surface and promote fungal growth.

[Anthony_Toronto]

Mulch was just small bark chips. Was sick of being inundated with weeds, but it seems the suffering performance of my plants over the last two years has been more of a problem than the weeds ever were (and the weeds are doing a very good job of growing in the mulch). Will be a rather large job to de-mulch the area, but maybe that is what I will have to do.

[Too Tall Toms]

Where did you get the mulch?

[Anthony_Toronto]

Local garden supply. I'm sure the mulch itself was not the problem, and that the nature of using landscape fabric and mulch, combined with the apparent abundance of fungal problems over the last few seasons, has simply created a favourable growth medium for fungus.

Are there any products (besides sulfur) that could be used to treat the mulch without harming the soil or plants?

[Too Tall Toms]

A few years ago my Mom got some free hardwood mulch from a nearby "dump"......it was a place where people threw cut grass, garden scraps, etc. Anyway she would go down to get this mulch whenever she needed to mulch some plants. Sometime shortly after that, we noticed septoria leaf spot(I think that's what it was called) scattered around the garden. It would only affect daisy-like flowers, galardias, and seedums. Copper sulfate powder was the recommended treatment.
Anyway, we put two and two together and figured out that free mulch must've been the culprit.

[habitat_gardener]

I'd get rid of the landscape fabric and leave the mulch. The landscape fabric may be making the plants' roots unhealthy, so even if you "treated" the fungi, the basic problem would remain. If possible, you can remove small sections of the fabric near some affected plants and see if this makes a difference.

How deep is the mulch? It can be up to 4-6 inches in root zones; any more than that can suffocate the plant (they need air!).

I almost always get odd mushrooms/fungi growing in bark mulch during the rainy season. They haven't harmed my plants, though.

[Suze]

Originally Posted by Anthony_Toronto

Are there any products (besides sulfur) that could be used to treat the mulch without harming the soil or plants?

Maybe a good spray or drench with some Actinovate? Edit/add - if I had a problematic soil or mulch situation (and also w/o knowing more about the specifics of what "fungus" or "blight" you are dealing with), that is probably what I would try first. Or maybe a combo of Exel LG and Actinovate.

[RayR]

The fungus species that grow on dead wood and bark are just doing their job, breaking it down. They are unrelated to the fungus and fungus-like pathogens that attack living plant tissue, but the conditions may be right in the mulch to harbor pathogenic spores that can splash up on the plants. The small bark chips may be contributing to the problem too, the experts say that a course bark mulch is less prone to fungal growth in landscapes.

I think Suze has the right idea, if fungus are dominating the mulch, it is probably because the acidic conditions are benefiting fungal growth and reproduction, but not benefiting healthy competition from bacteria. Inoculating the mulch with good bacteria may or may not help, it all depends on whether the environment of the mulch can sustain bacterial growth over time. and if those species of bacteria are effective in controlling the type of fungus thriving in the mulch.

I've experimented with landscape fabrics, plastic mulches and wood mulches before and they never reduced plant disease pressures in my experience, might even made it worse.
Compost mulch seems to work the best for disease prone veggies and to improve the soil also.

[PaulF]

I, too, have used different mulches but not wood mulches in my vegetable garden. Landscape fabric did an excellent job of weed control especially when covered with a straw mulch. I used a water permeable landscape fabric rather than a thick water holding style. Non-permeable plastic held the water and did seem to increase disease problems. Although that is a memory without proof. I did remove the mulch and fabric each fall and reinstalled it in the spring.

Newsprint groundcover with straw mulch works best for me. Minimal weeds and minimal disease pressure. I have used wood mulch around flowers and shrubs and have seen the fungii breaking down the mulch. It becomes nice compost after a few years.

[amideutch]

I agree with Suze. The timing of the applications is the key. Maybe hit it now with EXEL LG and come spring hit it with Actinovate and alternate with EXEL LG after that on a weekly basis. Might need to get a read from Boomer (Natural Industries). Ami

[Anthony_Toronto]

thanks for all of the advice. whatever the foliar problem is, it is slow moving but insidious. leaves turn crispy green, then brown. does not match any of the foliar diseases that i can find, but sure does seem to be some fuzzy fungal growth on at least some of the leaves. will try to post some links to pics (if i can find where i stored my pics).

Ok found some pics from July 2009, landscape fabric and mulch had just been applied a few months earlier...and this is pretty much what my plants looked like in 2008, 7, 6...etc:

http://www.flickr.com/photos/38701187@N08/6381388849/

http://www.flickr.com/photos/38701187@N08/6381384105/

http://www.flickr.com/photos/38701187@N08/6381378243/

http://www.flickr.com/photos/38701187@N08/6381372121/

And some from end of Aug 2011...largely the same varieties in pretty much the same spots as 2009 in the pics above...and this is what plants looked like in 2010 also. Late stage for development of the foliar problems. Started at the bottom with green leaves/branches drying out, then turning brown, then being pulled off...very different from typical yellowing of lower unproductive foliage, and natural shedding of lower branches by the plants.

http://www.flickr.com/photos/38701187@N08/6381365385/

http://www.flickr.com/photos/38701187@N08/6381359883/

[dice]

It is not verticillium. (That would have been my first guess given
your location.) If you look at the second picture on this page,
you can see how Verticillum affects the end of the leaf first.
I do not see that on your plants. edit: The link to the Verticillium
picture that I omitted: http://vegetablemdonline.ppath.corne...Vertic_Tom.htm

Botrytis? http://www.omafra.gov.on.ca/IPM/engl...gray-mold.html
(See if the descriptions of botrytis on the fruit rings a bell with what
you have seen in your garden.)

Maybe a really advanced case of Septoria Leaf Spot could look like that.

I was looking at pictures here:
http://www.omafra.gov.on.ca/IPM/engl...ers/index.html

Stuff that grows specifically on decaying wood is not going to affect
tomatoes. They are affected by fungi that infect live plants. The wood
can of course harbor spores of diseases like Verticllium, Botrytis,
Septoria, etc.

Finally, of course, it could be the dreaded fusarium wilt. Usually one can
see lesions on the stems, too, if that is it. Hard to get rid of. I did not think
it was particularly a northern disease, but Univ of Massachusetts mentions
it, so maybe it is known around there. It is the kind of thing that can build
up in the soil over time.

[RayR]

Looks like an advanced case of Septoria to me, sounds like it too from Anthony's description of the disease progression. That would make sense since Septoria spores could survive in the mulch over winter and come back at you the next year.

[Anthony_Toronto]

Stems don't seem to be impacted. Very little visible 'fuzz' anywhere. No greying that I can see. Leaves stay green, turn crispy green, then slowly turn crispy brown. Affects side branches, moving from the bottom of the plant upward. Fruits are not affected. It really does not seem to come even close to matching any tomato leaf disease pictures or description that I can find. Will try some general fungal treatments and get rid of the mulch if possible, and next year will take pics from beginning to end, as I know is it extremely difficult to tell anything from these end of season pics.