Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2003
Publication Date: 12/1/2003
Citation: Dorner, J.W. 2003. Long-term effects of application of nontoxigenic strains of aspergillus flavus and a. parasiticus to peanut soil for biological control of aflatoxin contamination. American Peanut Research and Education Society Abstracts. v. 35. www.apres.okstate.edu Interpretive Summary: NOt required for "abstract only"
Technical Abstract: Several studies have demonstrated the potential for biological control of aflatoxin contamination of peanuts by competitive exclusion using nontoxigenic strains of Aspergillus flavus and A. parasiticus. An eight-year (1995-2002) field study was conducted in southwestern Georgia to measure the long-term effects of application of nontoxigenic strains of A. flavus and A. parasiticus to peanut soil. Six distinct 0.25 acre plots (24 rows 150 ft. long) were treated with various nontoxigenic strains using different formulations and application rates during those years. Six equivalent plots in a different part of the field served as untreated controls. For the first five years (1995-1999) plots were planted to peanut, and "treated" plots were inoculated with nontoxigenic strains each year. Plots were not inoculated in 2000-2001 during which time a cover crop of rye was present. Plots were again planted to peanut in 2002 and treated plots were again inoculated. Monitoring of soil for A. flavus and A. parasiticus population densities in the spring and fall of each year beginning in 1996 showed that application of nontoxigenic strains significantly reduced the incidence of toxigenic A. flavus and A. parasiticus in soil. The incidence of toxigenic strains averaged > 95% in control plots compared with < 5% in treated plots. Total A. flavus and A. parasiticus populations were variable, sometimes being greater in control plots and sometimes greater in treated plots. Peanuts were exposed to late-season drought in 1997, 1999, and 2002, and were contaminated with aflatoxin each of those years. However, mean aflatoxin concentrations in peanuts from treated plots were reduced by 91.6, 89.5, and 98.3%, respectively, in each of those years.