Effects of Three Foliar Diseases on Biomass and Seed Yield for 11 Cultivars of Subterranean Clover. M. J. Barbetti, Plant Pathologist, Western Australian Department of Agriculture, Baron-Hay Court, South Perth 6151, Western Australia. Plant Dis. 71:350-353. Accepted for publication 18 September 1986. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1987. DOI: 10.1094/PD-71-0350.

The losses in subterranean clover sward production and seed yield from foliar disease caused by Cercospora zebrina, Kabatiella caulivora, and Pseudopeziza trifolii were determined for 11 cultivars at a single field site in southwestern Western Australia. Benomyl sprays gave excellent control of C. zebrina and K. caulivora and often good control of P. trifolii. Foliar disease resulted in significant decreases (9–32%) in biomass (sward) production in five of the cultivars examined. All three pathogens were shown to be able individually to decrease sward production in at least one of the susceptible cultivars tested. In all but one cultivar, there were large decreases (25–91%) in seed yield from foliar disease, and overall mean seed yield decrease was 38%. K. caulivora or P. trifolii individually, or C. zebrina in combination with P. trifolii, were shown to decrease seed yield. This is the first record of P. trifolii causing yield losses in subterranean clover.