1a.Objectives (from AD-416)
Design, develop, and evaluate area-wide approaches to aflatoxin elimination using atoxigenic strains of A. flavus. Research characteristics required of processes and equipment for production of inoculum by grower run organizations. Produce inoculum and assess commercial compatibility and efficacy of the area-wide approach.
1b.Approach (from AD-416)
In consultation with Arizona growers and gins, an area-wide aflatoxin elimination program based on atoxigenic strain technologies will be designed and tested. Inoculum production will be scaled up and equipment designed and modified to permit production of sufficient inoculum for evaluation of an area-wide program. Requirements for the different stages of inoculum production will be empirically determined. The economics of atoxigenic strain based programs will be assessed and area-wide influences of atoxigenic strain applications will be quantified.
Research activities are carried out both at the Arizona Cotton Research & Protection Council (ACRPC) and at the Agricultural Research Service (ARS) laboratories in Tucson. In 2010, analyses were continued on both short and long-term area-wide influences of multi-year applications of AF36, the biocontrol strain of Aspergillus (A.) flavus which does not produce the potent carcinogen, aflatoxin, to cotton fields in Arizona. Both crop and soil samples were analyzed for aflatoxin producing ability. Thousands of isolates of A. flavus were placed into the S and L morphotypes (i.e. with different morphological characteristics) and the L morphotype isolates were classified by vegetative compatibility analyses (examining whether cell material from two strains will fuse) as either belonging to the same vegetative compatibility group as AF36 or not. This provided insight into the extent to which treatments continued to be effective. Throughout the reporting period, ACRPC continued to convey information on the results of these studies to the grower community within Arizona and worked towards optimizing use of AF36 in Arizona. Information was also transferred to grower communities in Texas and California. Trials were continued on 1,000 acres of pistachios in Arizona and biocontrol material was supplied to California pistachio growers to treat 3,000 acres. During the subject period, a full registration, on corn was received from Environmental Protection Agency (EPA) and ACRPC worked to facilitate the use of AF36 on expanded acreage in Texas. Work also continued in collaboration with the laboratory in Tucson on improving formulations of AF36 and developing new, more cost effective manufacturing procedures. Development of biocontrol product with improved cost efficiency is a key objective as it will increase the frequency with which farmers will utilize aflatoxin biocontrol products. Efforts to design new manufacturing procedures included consultations with United States Department of Agriculture (USDA) personnel working for both Animal and Plant Health Inspection Service (APHIS) and ARS and with personnel working for the Bill and Melinda Gates Foundation. Large scale production of sorghum based product providing a significant cost benefit over wheat based product was an emphasis and an additional year of field studies was performed with the Tucson lab. Research progress is monitored through phone conversations, laboratory visits, and team visits to collaborating industry members.