ARS | Publication request: Efficacy of Pichia anomala WLR-076 to control aflatoxin on corn in Texas, 2005

Submitted to: Plant Disease Management Reports
Publication Type: Other
Publication Acceptance Date: March 1, 2007
Publication Date: March 1, 2007
Citation: Isakeit, T., Betran, F.C., Odvody, .G., Hua, S.T. 2007. Efficacy of Pichia anomala WLR-076 to control aflatoxin on corn in Texas, 2005. Plant Disease Management Reports. 1. Available: http://www.plantmanagementnetwork.org/pub/trial/PDMR/volume1/sections/FC.asp.

Interpretive Summary: Aflatoxins are regulated under the federal Food, Drug, and Cosmetic Act (FFDCA). National economic losses are in the billions of dollars per year due to aflatoxin contamination of agricultural commodities. Even very low levels of infection of crops by A. flavus can result in aflatoxin levels above the mandatory standard, which is unacceptable for human consumption. A strain of yeast , Pichia anomala strain WRL-076 was shown to reduce aflatoxin production and spore formation of A. flavus.. Field tests were conducted in Texas ob hybrid corn. The results indicated that there was a trend of reduced aflatoxin levels with P. anomala treatments, but there was a significant (P=0.05) reduction in aflatoxin with two applications of P. anomala at Weslaco.

Technical Abstract: The experiments were conducted at three Texas Agricultural Experiment Stations on yellow corn hybrids to test the biocontrol yeast, Pichia anomala WRL-076. There were five replicates per treatment arranged in a randomized complete block design. The treatments were: (1) P. anomala WLR-076 applied when corn was at 50% silking; (2) P. anomala WLR-076 applied when corn was at 50% silking, then again two days later; (3) no yeast application (control). Only the top ears of corn in the two middle rows of replicates were treated. All plots were inoculated with Aspergillus flavus by placing corn kernels colonized by the fungus on the ground in between the rows. The yeast suspension was sprayed onto silks and adjacent portions of ears until run-off using a backpack sprayer and a hollow cone nozzle. The top ears from the two middle rows of plots were harvested. All corn from each replicate was ground using a Romer mill and aflatoxin was quantified from 50-g subsamples using the VICAM Aflatest fluorometer. Aflatoxin concentrations in ng/g were log-transformed to equalize variance. P. anomala treated corn showed a significant (P=0.05) reduction in aflatoxin at Weslaco. Aflatoxin was significantly reduced on Pioneer Brand 31B13 after two spray of P. anomala in Weslaco, Texas.