Grapevine nursery plants have been reported with latent infections of Botryosphaeria dieback (BD) pathogens. However, it is unclear if the BD infections in nursery plants contribute to the disease incidence observed in vineyards. Recent studies also showed that water-stress can increase the susceptibility of young vines to BD. However, latent infections have no internal or external symptoms and may be randomly distributed within a vine, thus, accurate quantification of the incidence and severity of infection is difficult. Investigations on the effects of water stress on young vines artificial ly inoculated with three different conidial concentrations of Neofusicoccum luteum may provide insight on the infection thresholds that result in disease expression in vineyards. A published inoculation method using a vacuum was evaluated for infiltrating 300 (low), 3,000 (moderate) and 30,000 (high) conidia of N. luteum into dormant grapevine canes (cv. Shiraz). Ringers solution was used to vacuum-inoculate control vines. The qPCR analyses showed the vacuum-inoculation was a reliable method, resulting in the pathogen infecting the basal, middle and apical part of the inoculated canes. qPCR analyses also differentiated the low, moderate and high infections with the highest amount of pathogen detected from canes inoculated with 30,000 conidia and the lowest from those inoculated with 300 conidia. No pathogen was detected in any of the canes inoculated with Ringers solution. This study showed that different levels of N. luteum conidia can be vacuum-inoculated into dormant canes without significant impact on plant viability. The method was used to standardise infection levels of N. luteum in Shiraz rootlings in newly established glasshouse and shade house experiments aimed to investigate the effect of water stress on BD symptom expression.
|Publication status||Published - Nov 2019|
|Event||Australasian Plant Pathology Society Conference - Melbourne Convention and Exhibition Centre, Melbourne, Australia|
Duration: 26 Nov 2019 → 28 Nov 2019
https://researchoutput.csu.edu.au/admin/files/43820252/APP_2019_Program_Book_WEB_003_.pdf (Conference program)
|Conference||Australasian Plant Pathology Society Conference|
|Abbreviated title||Strong Foundations, Future Innovations|
|Period||26/11/19 → 28/11/19|