Fungal Detectives Uncover the Truth About
Green Mold By Amy
January 2, 2003
Pennsylvania farmers grow more mushrooms than farmers in any
other state, according to U.S. Department of Agriculture statistics. But in the
mid-1990s, farmers in Chester County--the states mushroom-growing
capital--came under siege, experiencing crop losses of 30 to 100 percent due to
a green mold epidemic.
Initially, scientists identified the green mold culprit as
Trichoderma harzianum, a common fungal species that has commercial
applications. Recently, however, scientists at the
Agricultural Research Services
Systematic Botany and Mycology Laboratory (SBML) in Beltsville, Md., gave this emerald
invader its true name: Trichoderma aggressivum.
T. harzianum has long been known for its beneficial uses.
It can be used to control other fungi that induce plant diseases, and it has
the potential to enhance plant growth. It has also been credited with degrading
pesticides in soil and preventing mycotoxin synthesis.
If T. harzianum were the fungus causing the green mold
epidemic, though, its commercial viability would be in jeopardy. For it would
be attacking mushrooms--a valuable and popular food commodity that U.S.
consumers spend more than $860 million on every year.
Dodd were not so sure that T. harzianum was the cause of the green
mold epidemic. Through their morphological and molecular studies, they were
able to exonerate T. harzianum and name a new Trichoderma
species. The scientists named this new species T. aggressivum
because of its aggressive nature against mushrooms.
Mushrooms are a good source of selenium, potassium and copper,
and some types have significant amounts of three B-complex vitamins.
more about their nutritional benefits and how the SBML researchers
identified the fungal attacker in the
December issue of
Agricultural Research magazine.
ARS is USDA's chief
scientific research agency.