Postharvest Biocontrol of Green and Blue Mold and Sour Rot of Citrus Fruit by Debaryomyces hansenii. Edo Chalutz, Institute for Technology and Storage of Agricultural Products, Agriculture Research Organization, The Volcani Center, Bet Dagan 50250, Israel. Charles L. Wilson, Fruit Pathology Unit, USDA, Agricultural Research Service, Appalachian Fruit Research Station, Kearneysville, WV 25430. . Plant Dis. 74:134-137. Accepted for publication 20 August 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1990. DOI: 10.1094/PD-74-0134.

The yeast Debaryomyces hansenii, isolated from the surface of lemon fruit, inhibited incidence of green and blue mold and sour rot of several citrus fruit cultivars. It was more effective against green mold than blue mold or sour rot. The lemon isolate of D. hansenii inhibited green mold on grapefruit more effectively than did any of eight other isolates of the same species. Efficacy of D. hansenii was maintained when applied simultaneously or prior to inoculation with Penicillium digitatum. Efficacy was reduced when D. hansenii was applied after inoculation. Control of green mold of grapefruit was maintained for 21 days at 11 or 22 C. The yeast antagonist also reduced the incidence of green mold decay of injured, naturally infected grapefruit stored at 11 C for 21 days. D. hansenii did not inhibit the growth in culture of P. digitatum, P. italicum, or Geotrichum candidum. A culture filtrate of the yeast antagonist failed to provide any protection against green mold of grapefruit. It may be that D. hansenii inhibits the pathogens by a mode of action other than antibiotic production.