ARS | Publication request: PREVENTION OF FUNGAL COLONIZATION AND GROWTH ON WOUNDS OF ALMOND NUT-FRUITS BY A BIOCONTROL YEAST IN ORCHARD

Submitted to: Extension Reports
Publication Type: Other
Publication Acceptance Date: December 19, 2005
Publication Date: April 1, 2006
Citation: Hua, S.T. 2006. Prevention of fungal colonization and growth on wounds of almond nut-fruits by a biocontrol yeast in orchard. Nickels Soil Laboratory in Cooperation with The University of California, Extension Reports.

Interpretive Summary: Aflatoxin contamination of nuts continues to be a regulatory deterrent to the tree nut industry. The growers and processors lose millions of dollars per year in testing, sorting and paying expenses to deal with rejection of aflatoxin contaminated nuts by importing countries. The biopesticide, P. anomala WRL-076 reduced fungal population including A. flavus on wounded almond fruits by 90% in comparison to control without yeast spray. Pichia anomala WRL-076 is not known to produce any toxic compounds or causes disease in plants and animals and humans. The cost of spraying yeast in orchards should be comparable with most other biopesticide. Thus, P. anomala is likely to provide an economical means of managing aflatoxin contamination and other undesirable fungal infection in almond orchard.

Technical Abstract: Existing literatures indicate that wounds in plant tissues provide the entry to A. flavus. and fungi. By mechanically wounding pistachio nut-fruits, sufficient number of nut-fruits conducive to A. flavus and fungal infection are generated. The wounded nut-fruits are easily recognized for sampling. Experiments were conducted at Nickels Soil Laboratory in the summer of 2004. Nut-fruits of almonds were individually wounded with a dissecting needle. Nut clusters were sprayed with water or sprayed with an aqueous suspension of yeasts at 5x107 cells/ml. The biopesticide, P. anomala WRL-076 reduced fungal population including A. flavus on wounded almond fruits by 90% in comparison to control without yeast spray.