Protecting Grapevines from Ozone Injury with Ethylenediurea and Benomyl

Soil and foliar applications of the antioxidants ethylenediurea (EDU) and benomyl were compared for their effectiveness in reducing oxidant stipple injury on Concord and Ives ( Vitis labruscana , Bailey) grapevine foliage. EDU was similar to benomyl in reducing oxidant stipple; but EDU did not have the fungicidal activity of benomyl on powdery mildew. Foliar applications of EDU were more effective than soil applications in reducing symptoms of oxidant stipple. EDU or benomyl applied at ozone episodes reduced oxidant stipple injury, but weekly applications of the antioxidants were more effective. EDU and benomyl were more useful in reducing oxidant stipple of Concord than Ives.