Effect of wart disease on survival and yield of the tropical pasture legume Desmodium ovalifolium

Desmodium wart, caused by Synchytrium desmodii, severely reduced soil seed reserves, seedling survival, and recruitment of adult plants of Desmodium ovalifolium ‘CIAT 350’ to the pasture sward from 1985 to 1988 at Carimagua in the eastern plains of Colombia. Under nonflooded conditions, wart did not reduce yield of adult plants of CIAT 350, while under intermittently flooded conditions, yield of CIAT 350 was reduced by 72.5%. Dry matter production of five accessions of D. ovalifolium was also greatly reduced in intermittently flooded, wart-inoculated treatments in another experiment. CIAT 13089 was distinguished by high dry-matter production under the same conditions. These serious effects of wart on legume yield and persistence will reduce long-term productivity and quality of perennial pastures based on D. ovalifolium.