Pensacola News Journal

For:  Saturday, Jan. 22, 2005

By:   Daniel E. Mullins

        Extension Horticulture Agent

        Santa Rosa County

 

 

Mysterious Bad Odor Occurring in Some Landscapes

 

 

            When some local residents say that their landscape stinks, they mean it literally.  The odor is that of rotting meat and is coming mostly from shrub and flower beds, but in some cases even from the lawn.

            This strange occurrence is the result of a fungus that decomposes organic materials that are high in cellulose.  There are several of these decomposing organisms which are broadly classified as the stinkhorn fungi, sometimes called stinkhorn mushrooms. 

            The one most commonly seen, or smelled, in Gulf Coast landscapes is the squid stinkhorn.  It arises from an egg-like structure that is attached to the ground by long strands.  The stinking part breaks through the “egg,” with several arms that join at the top.  The resulting structure is two to three inches tall and almost as wide.  It is usually yellow, later turning to a bright orange and contains a stinking fluid.

            Botanically this fungus is Clathrus columnatus , belonging to the Basidiomycete class and the order Phallales.  Though the fruiting structure reeks, it is an interesting species.

            Clathrus is one of the great decomposers of organic material such as leaves, twigs and dead branches.  Under forest conditions, it is an important part of the natural environment, helping to break down dead materials to simpler compounds.

            A problem for homeowners occurs when it does the same thing in your mulched landscape beds and lawns.  Woody debris left over from the recent hurricane has added to the potential food for this fungus.  It loves to grow in wood chips, sawdust, dead roots, stumps and other high cellulose containing materials.

            Most of the time the fungus is unseen, producing fine strands within the soil and dead organic material.  When it matures enough and when weather conditions are right, it reproduces by developing the smelly fruiting bodies.           Spores are produced on the fruiting structure within a slimy, stinking substance.  Certain insects, especially flies, are attracted and then spread the spores to other areas.

            Even when the fungus is actively growing in certain areas, the mushrooms do not occur constantly, appearing for several weeks once or twice per year.  So homeowners who are being grossed out by the odor can take heart in the fact that they are seasonal.  Also, the fungus growth and fruiting will decrease as the available dead organic material advances in decomposition.  Depending upon the amount of food present, this time can vary from months to several years.

            There is no safe chemical control that can be recommended, so if relief is necessary only cultural methods can be used.  First look around to see if you are providing a food source for the fungus.  Remove sawdust piles, dead roots and underground stumps if feasible.  This fungus particularly likes fresh hardwood chips and it grows and fruits profusely when this material is used as mulch.

            Sometimes it is most practical to simply move the mushrooms as they occur.   Using a shovel – preferably a long handled one, carefully scoop up and move each one away from the house.  Though a fungus, stinkhorns don’t cause plant disease, so they can be deposited in more remote areas of the yard or even in the compost pile without concern. 

 

Question of the Week:  Tomato spotted wilt virus killed my tomato plants last year.  Are there any varieties that are resistant?

Answer:  A few varieties have been developed that show resistance to this disease.  They include Amelia, Quincy, Top Gun and Christa.  These are new varieties which have been tested for several years and have only recently been released.  They will likely be difficult to find and seed might not be available except in larger, commercial sized packages. 

 

Note to the Editor:

Attached are two photos of these stinking mushrooms!

Photo 1:

     

Caption:  Squid stinkhorn showing the “egg” and the mature stage.

 

 

Photo 2:

Caption:  A thick layer of chipped oak wood provides an ideal environment for the stinkhorn fungus.