Competition, displacement would favor less pathogenic strain "We can deliver this with typical granular application equipment," he says. "We inoculate the soil right around where these peanuts are pegging in the soil.
"Based on the formulation alone, it would cost about $5.80 to put out 20 pounds per acre. Earlier studies have shown that the more material we apply, the better control we'll get. We're in the early stages of talking about commercializing this method.
"The peanut industry has told us we need to do this for about $20 per acre or less. Even at 50 pounds per acre, we still can keep that cost under $20 per acre. Realistically, this is the range we're looking at for having an effective formulation at an affordable price."
Field tests using the 20-pounds-per-acre formulation have resulted in a 92 percent reduction in the amount of aflatoxin in a one and a half acre peanut field, according to Dorner. This was a worst-case field scenario with late-season drought, he says.
Drastic reductions in the amount of toxigenic A. flavus contamination also were seen in storage studies, where peanuts in storage were subjected to high humidity and temperatures to encourage contamination. The treated peanuts showed significantly less contamination than the untreated peanuts, reports Dorner.
"These tests demonstrated the carry-over effect that treating these peanuts out in the field can have in a storage situation where poor conditions exist."
If this technology is to be commercialized, the first step would be an experimental use permit (EUP) issued by the Environmental Protection Agency, says Dorner.
"The EPA might ask questions such as, `What about the amount of A. flavus in the crop?' Data indicates that we do not increase the overall amount of A. flavus in peanuts with the use of this technology. We're simply replacing the toxigenic strain of aflatoxin."
The EPA also might question the amount of aflatoxin in the environment, he adds. The agency will focus, he says, on whether or not there's a greater exposure to A. flavus as a result of using this biological control method.
"Finally, pathogenicity tests may or may not be required to prove that the strains of A. flavus being used are not more pathogenic to insects or birds than the normal strains of aflatoxin."
The second big step in commercializing this method will be increasing the production of the formulation, says Dorner. "If we are successful in obtaining an EUP, we'll need to produce an amount of the formulation necessary to cover the acreage allowed under the experimental use permit."