Submitted to: Acta Horticulture Proceedings
Publication Type: Book / Chapter
Publication Acceptance Date: 11/8/2005
Publication Date: 11/1/2008
Citation: Doster, M.A., Michailides, T.J., Doster, L., Cotty, P.J. 2008. Biocontrol of aflatoxins in figs. In: Leitao, J., Neves, M. A., editors. III International Symposium on Fig. Vilamouran, Algarve, Portugal. 798:223-226. Interpretive Summary: Aflatoxins are toxic fungal metabolites that can inhibit human development, cause cancer and even induce death. Preventing the occurrence of these toxins in foods is very difficult. A biological control that uses strains of Aspergillus flavus to prevent aflatoxin contamination has been developed by ARS and is being evaluated for use of figs in California. Initial results suggest that this biological control strategy shows promise for reduction of aflatoxin contamination on figs. Further evaluations are required before commercial orchard testing is pursued.
Technical Abstract: For several years, we have investigated the use of atoxigenic strains (strains not able to produce aflatoxins) of Aspergillus flavus as biocontrol agents to reduce aflatoxin contamination of figs in California. The atoxigenic strain AF36 has been successful in reducing aflatoxin contamination of cottonseed in commercial cotton fields in Arizona. Approximately 6 percent of the A. flavus isolates obtained from commercial fig orchards in California belonged to the atoxigenic strain AF36. In 2003 and 2004, AF36 was applied in a Calimyrna fig orchard. In early summer, wheat seeds infected with AF36 were applied at the rate of 11.2 kg/hectare to the orchard floor. Almost all A. flavus isolates obtained from noncaprified figs collected from the orchard floor belonged to the applied strain AF36, indicating that AF36 had colonized debris in the orchard. In late summer, leaf and soil samples were collected. Results indicate that atoxigenic strains continue to show promise for the reduction of aflatoxin contamination of figs.