Show simple item record Sharman, Murray 2021-03-29T23:31:44Z 2021-03-29T23:31:44Z 2019-06
dc.description.abstract This project aimed to enhance and support the sustainability of the Australian cotton industry by: providing continued capacity in plant virology expertise and diagnostics, building industry awareness of viral disease threats, and developing preparedness for viral diseases that pose serious biosecurity threats to the Australian cotton industry. Disease surveys targeting viruses in northern Australia were done over 4 years in areas that may be exposed to possible incursion pathways for biosecurity threats and also in emerging cotton production regions in far northern Western Australia and Queensland. No viruses were detected in cotton production areas of Kununurra and northern QLD. However, six different polerovirus species were detected in other hosts. None of the newly detected poleroviruses are likely to affect cotton but it does indicate there is a diverse range of poleroviruses in northern Australia and emerging cotton production regions may be exposed to new virus threats. Disease surveys were also done in commercial cotton in Queensland. From 158 disease counts from 35 farms, no symptoms typical of exotic viruses were seen. Generally, there was very low incidence of virus-like symptoms for endemic viruses (Cotton bunchy top virus – CBTV and Tobacco streak virus - TSV) in cotton crops inspected with the exception of a few sporadic disease outbreaks of CBTV. Old volunteer or ratoon cotton appears to be the major source of infection for CBTV moving into crops and as such it is recommended to maintain effective crop hygiene to break the infection cycle and reduce the risk of virus disease outbreaks. This project has confirmed that two distinct polerovirus species infect cotton in Australia, CBTV-1 and CBTV-2. We found that CBTV-2 is always associated with disease symptoms in cotton while CBTV-1 is not. All symptomatic plants were infected with CBTV-2, either with or without CBTV-1. This will help to focus any future work on the control of CBTV-2 which is likely the only causal agent for disease while it appears that CBTV-1 is most likely non-symptomatic in cotton and of little concern. Three virus surveys were done in Timor-Leste (East Timor) with the primary focus to establish how common Cotton leafroll dwarf virus (CLRDV) is and what potential threat there may be for incursion into Australia. Gossypium samples were collected from across much of the country and CLRDV was detected from more than 30% of plants tested from several sites. Hence, CLRDV in Timor-Leste was found to be relatively common and widespread in three Gossypium species (G. arboreum, G. barbadense and G. hirsutum). Improved diagnostics developed for CLRDV strains from Timor-Leste, Thailand and other countries will support preparedness for this biosecurity threat. Other new poleroviruses were also found in Timor-Leste and northern Australia, suggesting there may be natural movement of virus-infected aphids in wind currents from Timor-Leste. This example of potential virus movement may be of concern for the expansion of cotton production in northern Australia. en_US
dc.description.sponsorship Cotton Research & Development Corporation en_US
dc.publisher Queensland Department of Agriculture and Fisheries en_US
dc.relation.ispartofseries DAQ1601;
dc.title Surveillance and studies for endemic and exotic virus diseases of cotton en_US
dc.type Technical Report en_US

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