The Lima Bean Scab Situation

Abstract

Lima bean scab, due to the fungus Elsinoe canavaliae , is a disease confined to this host. It is probably endemic in the Central American and West Indian regions, and is not known to occur in the United States. Being a well specialized parasite the fungus does not seriously injure its host, the outstanding damage arising from disfigurement of the pods. The evidence points to inter-season carry-over on living plants and to spread by wind. Temperature and moisture relations in Cuba indicate that it might be troublesome in at least some of our lima bean areas. Its relation to a long winter and frost are unknown and these might be limiting factors in the north. Successful control by spraying requires numerous applications involving excessive cost. The chief danger of introduction lies in the discarded pods, which may reach our fields by way of garbage. Point-of-origin inspection and certification is unsatisfactory; it both throws out too much of the crop and yet allows considerable scab infection to remain. Importation of lima beans in the shelled condition under refrigeration in transit would assure adequate protection and is regarded as a commercial possibility.