Submitted to: Aflatoxin and Food Safety
Publication Type: Book / Chapter
Publication Acceptance Date: April 6, 2004
Publication Date: October 28, 2005
Citation: Horn, B.W. 2005. Ecology and population biology of aflatoxigenic fungi in soil. Aflatoxin and Food Safety. CRC Press, Boca Raton, FL. Interpretive Summary: Aspergillus flavus and A. parasiticus form carcinogenic compounds called aflatoxins that contaminate agricultural commodities destined for human and animal consumption. These fungi reside in soil where they produce spores that infect peanuts, corn, cottonseed and tree nuts. Climate and crop history in different geographic regions of the United States greatly affect the density and aflatoxin-producing ability of soil populations. Infected crops during drought years periodically replenish soil populations of these fungi. A thorough understanding of the activities and population structure of A. flavus and A. parasiticus in soil is necessary for developing effective measures to control aflatoxin contamination of crops.
Technical Abstract: Soil serves as a reservoir for Aspergillus flavus and A. parasiticus, fungi that produce carcinogenic aflatoxins in agricultural commodities. Populations in soil are genetically diverse and individual genotypes show a clustered distribution pattern within fields. Surveys over large geographic regions suggest that climate and crop composition influence species density and aflatoxin-producing potential. Aflatoxigenic fungi reside in soil as conidia, sclerotia and hyphae, which act as primary inocula for directly infecting peanuts or for infecting aerial crops (corn, cottonseed, tree nuts) through wind and insect dispersal. Infected crops periodically replenish soil populations during drought years.