Effect of seed treatments and root pathogens on seedling establishment and yield of alfalfa, birdsfoot trefoil and sweetclover

Abstract

Soil-borne fungal pathogens can reduce stand density in alfalfa (Medicago sativa), birdsfoot trefoil (Lotus corniculatus) and yellow sweetclover (Melilotus officinalis) by reducing seedling establishment and subsequent stand longevity. Fungicide seed treatments containing metalaxyl and fludioxonil were examined in inoculated greenhouse and field tests to determine their efficacy against seedling blight and root rot caused by Fusarium avenaceum and Rhizoctonia solani. Inoculation increased disease severity and reduced establishment, especially in field trials inoculated with Rhizoctonia solani. Under controlled conditions, fludioxonil (alone or in a formulation with metalaxyl) was effective against either pathogen in inoculated trials-seed treatment consistently increased seedling survival and reduced root rot on all three forage species. However, seed treatment had little impact on subsequent forage yield under field conditions. Metalaxyl alone was not efficacious. In fields with high pathogen populations, application of fludioxonil seed treatment on forage legume species could improve seedling establishment substantially. © 2006 Asian Network for Scientific Information.