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 mosaic virus (SCMV‐SC) in a non‐persistent manner, whereas Melanaphis sacchari (Zehntner), Hysteroneura setariae (Thomas), Hyperomyzus lactucae (L.) and Aphis nerii Boyer de Fonscolombe did not transmit the virus. Calculated transmission rate per aphid was higher (12–16%) when sweetcorn 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 most prevalent aphids caught on sticky yellow traps in the Isis and Bundaberg districts in 1989–91. Three vector species, A craccivora Koch, A. gossypii and R. maidis, were trapped mainly in spring, summer and autumn, and a fourth vector species, R. padi (L.) was trapped only in winter. Since vector species were active during all seasons, there is always potential for transmission of SCMV‐SC if host, virus and environmental factors are favourable. Copyrigh

An abrasive pad rubbing method for inoculating sugarcane with sugarcane mosaic virus

An abrasive pad rubbing method was developed for inoculating sugarcane plants with sugarcane mosaic virus (SCMV). This method involved moistening an abrasive pad with sap extract containing SCMV and carborundum, folding the pad around the base of the youngest fully expanded leaf, and pulling the pad towards the tip of the leaf. The abrasive pad method was as effective as, and much less laborious than, inoculating the spindle leaf by Sein’s pricking method. Differentiation of resistant and susceptible sugarcane varieties was better when plants were inoculated at the advanced tillering stage than at either the 2-3 leaf or the tillering stages. In SCMV resistance trials done over 4 years with a set of eight ‘standard’ varieties, correlation coefficients of 0.92 to 0.99 were obtained for level of infection and disease ratings, indicating a high level of reliability of the rub inoculation method