Prune trees planted next to vineyards allow early-season buildup of Anagrus epos, an important parasite of the grape leafhopper. After surviving the winter on an alternate host, the prune leafhopper, Anagrus moves into the vineyard in the spring, providing grape leaf-hopper control up to a month earlier than in vineyards not near prune tree refuges.

The authors express their appreciation for funding provided by the California Raisin Advisory Board, the California Table Grape Commission, and Winegrowers of California.