Title: Thrips and seed transmission, and the epidemiology of Tobacco streak ilarvirus in Queensland Australia
Abstract: Tobacco streak virus (TSV) is transmitted by thrips and has recently been reported from several important crops in central Queensland Australia, including sunflower, mungbean, chickpea and cotton (Sharman et al. 2008). In recent years there have been important economic losses in sunflower and mungbean crops. However, until recently little was known about the causal strain of TSV or its key alternative hosts in the region. TSV was found to occur commonly in Parthenium hysterophorus, as symptomless infections, in central Queensland across a large area infested with this highly invasive and prolific weed (Sharman et al. 2009). Several isolates of TSV collected across the geographic range of P. hysterophorus were found to share identical coat protein sequence with each other and with TSV from crop plants in the same area. TSV is a pollen-borne virus and transmission relies on the virus particles from infected pollen entering plant cells through the feeding injury caused by thrips. The central Queensland strain of TSV was shown to be readily transmitted by the commonly collected species, Frankliniella schultzei and Microcephalothrips abdominalis using TSV-infected P. hysterophorus pollen. Seed transmission of TSV in P. hysterophorus occurred at rates of 6.8 to 48% and there was almost no change in this rate when P. hysterophorus seed was stored for up to 24 ½ months. These results indicate that P. hysterophorus is a key alternative host for the development of TSV disease epidemics in surrounding crops in central Queensland. [Murray Sharman, D.M. Persley1 and J.E. Thomas (2010). Thrips and seed transmission, and the epidemiology of Tobacco streak ilarvirus in Queensland Australia. Journal of Insect Science, Vol. 10, Article 166, n.p.]