Comparative efficacy of ozone-injury suppression by benomyl and carboxin on turfgrasses

Abstract

The systemic fungicides benomyl and carboxin were evaluated in controlled environment chambers as ozone protectants on annual bluegrass (Poa annua L.), Kentucky bluegrass (Poa pratensis L. cv. Merion) and creeping bentgrass (Agrostis palustris Huds. cv. Penncross); and in open-top outdoor chambers on creeping bentgrass. Benomyl sprays were effective in reducing ozone-induced injury in controlled environments on all grasses at all rates used. Carboxin was not a satisfactory ozone protectant and had direct toxic effects on leaves of all 3 species. Growth retardation due to ozone or carboxin was generally proportional to leaf injury. Benomyl sprays in the outdoor situation limited ozone injury on creeping bentgrass for several weeks in the summer but for a much shorter time in the fall.