High-rate, deep-placement applications of the soil fumigant, 1,3-D, have been successful over a 3-year test period in controlling both the nematode vector, Xiphinema index, and the fanleaf-yellow mosaic virus disease of grapevines. A 250-gal-per-acre application rate appears to be necessary, especially on heavy soils, until results of trials with lower rates have been evaluated. Recent commercial applications of methyl bromide under continuous polyethylene sheeting indicate a good potential for control of fanleaf virus-dagger nematode disease; however, preliminary tests show that shallow applications do not give satisfactory control in the deeper layers of soil. Further tests are underway to improve the effectiveness of this material.

This work has been possible by the cooperation of many vineyardists including Christian Bros., Napa; George Guglielmo, Morgan Hill; and Karl Wente and Joseph Concannon, Livermore. The Shell Chemical Company provided the fumigants used in these experiments. Many members of the University of California Agricultural Extension Service also assisted, including W. H. Hart, Rudy Neja, John Joos and Douglas Hamilton.