HARMFUL SAC FUNGI

Ceratocystis ulmi

This fungus causes the Dutch Elm Disease.  This fungus first appeared in the U.S. in 1930.  Apparently it appeared in transported elm logs.  The main carrier of the disease are bark beetles that carry the fungus from tree to tree as they feed. The observable symptoms and the progression of the disease differ among trees which are inoculated through beetle feeding and those which are infected through root grafts. Trees infected by beetles first show wilting, curling and yellowing of leaves on one or more

branches in the upper portion of the tree. Large trees may survive and show progressively more symptoms for one or more years. Trees infected through root grafts wilt and die rapidly; this frequently occurs in the spring soon after the trees have leafed out and progresses from the base of the tree upward.

 

Endothia parasitica

This particular fungus has virtually eliminated the American Chestnut, as a commercial species, from eastern hardwood forests.  Although roots from trees cut or killed many years ago continue to produce sprouts that survive to the sapling stage before being killed, there is no indication that a cure for this disease will be found.  The fungus is widespread and continues to survive as a non-lethal parasite on chinkapin, Spanish Chestnut, and Post Oak.

The fungus forms yellowish or orange fruiting bodies about the size of a pin head on the older portion of the bark.  Spores may exude from these fruiting bodies as orange, curled horns during moist weather.

 

Claviceps purpurea

This fungus affects grains (rye and sorghum) during its overwintering stage of the grain’s life cycle.  The overwintering stage concentrates molecules called alkaloids as a metabolic by-product.  These alkaloids, can be highly toxic to humans and other animals.  Excessive consumption of rye flour contaminated by this fungus causes the disease ERGOTISM.  Below are ways in which this fungus can affect animals:

Extended periods of cool, wet weather can encourage the growth of this fungus.  It is most likely that much of the “witchcraft” of the Middle Ages and the trials that followed (including the Salem witch trials) were ultimately due to ergotism.  The first documented occurrence took place in Germany in 857 AD in which a “great plague of swollen blisters consumed the people by a loathsome rot, so that their limbs were loosened and fell off before death”.  When Peter the Great attempted to conquer port cities along the Black Sea, his troops ate contaminated rye flour and fed it to their horses, which came down with “blind staggers”.