ABILITY TO TRANSMIT SUGARCANE MOSAIC-VIRUS AND SEASONAL PHENOLOGY OF SOME APHID SPECIES (HEMIPTERA, APHIDIDAE) IN THE ISIS AND BUNDABERG DISTRICTS OF QUEENSLAND

Rhopalosiphum maidis (Fitch), Aphis gossypii Glover and Myzus persicae (Sultzer) transmitted the Australian sugarcane strain of sugarcane mo saic virus (SCMV-SC) in a non-persistent manner, whereas Melanaphis sa cchari (Zehntner), Hysteroneura setariae (Thomas), Hyperomyzus lactuca e (L.) and Aphis nerii Boyer de Fonscolombe did not transmit the virus . Calculated transmission rate per aphid was higher (12-16%) when swee tcorn was the source of SCMV-SC than when sugarcane was the source (2- 5%). M. sacchari (a non-vector) and A. gossypii (a vector) were the mo st prevalent aphids caught on sticky yellow traps in the Isis and Bund aberg districts in 1989-91. Three vector species, A craccivora Koch, A . gossypii and R. maidis, were trapped mainly in spring, summer and au tumn, and a fourth vector species, R. padi (L.) was trapped only in wi nter. Since vector species were active during all seasons, there is al ways potential for transmission of SCMV-SC if host, virus and environm ental factors are favourable.