Citrus Could Get Microscopic Ally in Battle of the Rots

Tomorrow's grapefruit, oranges, lemons and limes might have a powerful ally to help them resist attack by microbes that cause costly decay. Scientists with the Agricultural Research Service and Texas A&M University have discovered a beneficial microbe that fights green mold on citrus in laboratory tests.

Researchers say the microbe--a helpful strain of a fungus--is easy to raise and harvest in the laboratory, and might someday reduce or eliminate the need for certain after-harvest fungicides.

The fungus is named Geotrichum candidum (gee-OUGHT-tree-come can-DEE-dum), strain AVIR. It is a beneficial or "avirulent" strain of the G. candidum fungus. In nature, wild or virulent G. candidum is the well-known cause of the fruit disease called sour rot.

Dipping, spraying or dusting fruit with a beneficial microbe to ward off rot-causing organisms is not new. But ARS and Texas A&M researchers were first to discover and test the avirulent G. candidum strain. They did the laboratory experiments with grapefruits and oranges, and suspect the microbe could be employed safely and effectively to protect other fruits as well, including apples, pears and strawberries.

Cynthia G. Eayre of the ARS Horticultural Crops Research Laboratory, Fresno, Calif., leads the research. Eayre and colleague Mani Skaria of Texas A&M University have patented their discovery.

Scientific contact: Cynthia C. Eayre, ARS Horticultural Crops Research Laboratory, 2021 S. Peach Ave., Fresno, CA 93727, phone (209) 453-3162, fax 453-3088, ceayre@asrr.arsusda.gov.