Description

Abstract: Transmission of the causal agents, isolated in Nigeria, of two forms (chlorotic rosette and green

rosette) of groundnut rosette by the cowpea aphid, Aphis craccivora, was compared in concomitant experiments. Aphids could acquire groundnut rosette virus (chlorotic) (GRV-C) within 4 hr and groundnut rosette virus (green) (GRV-G) within 8 hr. For both GRV-C and GRV-G, latent periods varied from 1 to 1 I days; median latent periods were 26.4 and 38.4 hr for GRV-C and GRV-G, respectively. After a 24-hr latent period, viruses of both diseases could be transmitted within 10 min (inoculation access period). Multiple plant infections (serial transfers) tended to occur more frequently with GRV-C than with GRV-G. Maximum retention time was the lifetime of aphids (about 14 days) for both viruses. Overall transmission efficiency of GRV-C and GRV-G increased from 26 to 3 1 to 49% when one, two, and five aphids, respectively, were allowed to feed on test plants. No major differences in transmission efficiency of GRV-C and GRV-G were detected, however, with increased numbers of aphids.