Here's a question for the master gardeners:  a lovely bed of shallots, a separate 4x4 raised bed, is showing a white fungus clinging to the bulb roots beneath the soil surface.  Fluffy, obvious stringing, some near solid clumps and the presence of three 6" mammoth mushrooms that tipped me to trouble yesterday.  Initially I thought it might be white onion rot after a google search, but a query sent to the source of the larger shallots, Territorial Seed, brought back this reply:

Ruthmarie,
Thank you for the heads up. I haven't had any other mention of white rot problems with Matadour. If it is white rot, then the leaves decay at the base, turn yellow, wilt, and topple over. Older leaves collapse first. Roots are rotted, and the top of the plant can be pulled out of the ground easily. Fluffy white mycelium may be on remaining roots and bulb. The affected bulb may become watery, and the outer scales crack as it dries and shrinks. Small sclerotia (masses of hardened fungus) form in affected bulb parts and on the surface, often around the neck. Sclerotia are smaller and rounder than those of the neck rot disease.
Are you seeing any of the above symptoms? If not, I think the fungus you are observing is the organic matter in the soil breaking down. If you are seeing these symptoms, then you need to remove and destroy the infected bulbs.
Marlece

It just breaks my heart that the whole bed may need ultimate disposal as there's near 15-18 pounds of allium lusciousness in there … none of the bulbs appear to be rotting, 80% of the leaves are green and hearty (some older leaves have withered but it's been whackin' hot lately!).  I did harvest several clumps about 3 weeks ago that had dry tops, not noting anything unusual, and we've eaten several to no ill effect.  The soil & mold doesn't smell sour, just dang disturbing in its gray proliferation.  Any thoughts?  Anyone else deal with this little surprise before?  Fungus doesn't appear in any other raised bed in the veggie lineup but this is a shallow 6" bed and might have had drainage issues (?).  Suggestions would be most welcome!  :^)

A couple of days down the road and a conversation with a local Master Gardener (there's a hotline), I'm convinced it's simply … and happily … a fungus running amuck in the soil.  Thank you, hershiesgirl, for taking the time to offer reassurance. I am so relieved!

DH has offered to take the small bed apart after we've harvested the shallots … which was rarely all that soggy (the soaking big storm in early June started it?) … and it will be pieced with other wood for a deeper raised bed for a dwarf Meyer lemon. The soil will be recycled into the compost where fungi will not give me heart failure.

gakaren said:

Ruth, you can generally tell that it is organic matter breaking down when mushroom appear.

Glad you got your answer from a MG!  Sorry, I was late to the party!  And HG, was right, not all fungus is bad, some are very needed to help all the biology happen under the top of the soil.

When I first spotted the mushrooms, there was an initial thought of "no harm" but, honestly, I slid into panic when I realized white fluff was gripping all those allium tushies throughout the whole bed!  It looked so alien.  I've never seen organic breakdown widespread but now I know better (relatively new gardener of only 4 years).  One of these days I'll pass the advice forward to another who is showing the whites of her eyes ….

Liz Pike said:

Hi Ruthmarie, I'm "late to the party" too.  Did you mulch your shallots, and if so, with what? 

Nope, no mulch, just a refresh with seasoned manure last year (which may be the culprit in breakdown) … I did research on growing and harvesting before attempting a higher end crop.  I was up on shallots don't like smothering, just maintain the weeding.  I'm in central CA which has mild winters, rarely dropping below freezing.  I'm also growing multiplier onions for the first time which behave much like shallots … that bed is twice as deep and no surprises.  The only conclusion I've deducted is that the shallow bed the shallots are in didn't drain as easily into the stubborn ground granite + clay underneath that is a thin cover for concrete bedrock.  Lesson learned.  No shortcuts on the native dirt.

Oh my goodness … Mycelium and Allium are having a love tryst in my garden!  Suddenly the fluffy grey alien seems so much more innocuous despite the passionate snuggle on allium tushies.  I'll go out and apologize to the alliums drying in the garage that I ripped out of the mycelium embrace while trying to decide what the white fungi was all about.  (Before I eat them, heheh)  I think you're right, Liz, about the mycelium … a quick look for web images looks very much like some of the dense patches I found.  May have to do some more reading … I wonder if mycelium is as fond of other root crops?  DH is going to eye-roll if I suggest creating a bed of meandering mycelium …..

Oops, didn't explain our local soil that well … it isn't impervious nor rock solid.  It's ground rock mixed with mucho clay that requires more amendments to fluff it up than building the beds.  And we have invasive weed issues that came with the house.  Our raised beds, with the exception of the shallow bed, were built two 8" boards high, are not sunk in the soil but were bottom-lined with layers of newspaper before filling with amended soil (infernal bermuda creeps under the edges!).  Even with the frequent watering required in high summer heat, rarely is there a soggy issue in the deeper beds.  But the shallow bed is definitely too short thanks to all of your welcome input!  <img class="sfsmiley" title="yes" onclick="sfjLoadSmiley('icon_yes.gif', 'yes', 'http://chickensintheroad.com/w…..eys/', '', '1');" src="/wp-content/forum-smileys/icon_yes.gif" alt="yes" />