ARS | Publication request: Use of a Granular Bioplastic Formulation for Carrying Conidia of a Non-aflatoxigenic Strain of Aspergillus flavus

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 4, 2009
Publication Date: April 5, 2009
Citation: Accinelli, C., Sacca, M.L., Abbas, H.K., Zablotowicz, R.M., Wilkinson, J.R. 2009. Use of a Granular Bioplastic Formulation for Carrying Conidia of a Non-aflatoxigenic Strain of Aspergillus flavus. Biological Control. 100:3997-4004, 2009.

Technical Abstract: Previous research demonstrated that aflatoxin contamination in corn grown in Mississippi is reduced by field application of wheat grains pre-inoculated with the non-aflatoxigenic Aspergillus flavus strain NRRL 30797. To facilitate field applications of the biocontrol isolate, a series of laboratory studies were conducted on the reliability and efficiency of replacing wheat grains with the novel bioplastic formulation Mater-Bi® to serve as a carrier matrix to formulate this fungus. Mater-Bi® granules (5 mm long and 3 mm diameter) were inoculated with a conidial suspension of NRRL 30797, dried at 40 °C for two hours, to achieve a final cell density of ' log 7 conidia granule-1. The A. flavus strain was also formulated in Pesta granules and applied to microbiologically active or sterilized soil samples. Incubation of 20-g soil samples receiving a single Mater-Bi® granule for 60-days resulted in log 4.2 to 5.3 propagules of A. flavus g-1 soil for microbiologically active and sterilized soil, respectively. Increasing the number of granules had no effect on the degree of soil colonization by the biocontrol fungus, as evaluated by cultural methods and quantitative PCR. In addition to the maintenance of rapid vegetative growth and colonization of soil samples, the bioplastic formulation was highly stable. The formulations shelf life is comparable to that of the widely used wheat based “Pesta” granules, indicating that Mater-Bi® is a suitable substitute for biocontrol applications of A. flavus NRRL 30797.