Seed-borne Fusarium species on subterranean clover and other pasture legumes

Abstract

Fusarium avenaceum (Corda ex. Fr.) Sacc. was detected for the first time on seed of strand medic (M. littoralis Rhode), lucerne (M. sativa L.), white clover (T. repens L.) and strawberry clover (T. fragiferum L.). The percentage of seed infected was 24% on medic seed, 2–3% on strawberry clover, 2–6% on white clover, and 10–14% on lucerne, compared with 1–42% on subterranean clover seed. The majority of infected seed lines were grown in the main seed-producing areas of Victoria. F. arthrosporioides Sherb., F. equiseti (Corda) Sacc., F, acuminatum Ellis & Everhart and F. culmorum (W. G. Sm.) Sacc. were isolated from subterranean clover seed for the first time, comprising between 1 and 8% of Fusarium spp. isolates, while F. oxysporum (Schlecht) and F. avenaceum comprised the remaining 55% and 35% of isolates respectively. In laboratory tests, isolates of F. avenaceum from each seed host were all strongly pathogenic on roots of subterranean clover, but there was no evidence of pathogenicity by other Fusarium spp. F. oxysporum had no effect on the severity of root rot disease either alone or in combination with F. avenaceum.