Integrated management of grapevine phylloxera: Phase II

Summary

Objective

This project is a next-phase research program that will procure knowledge to improve phylloxera management practices and help protect Australian vineyards. It aims to address five key research components:

1. more effective surveillance and diagnostics
2. improved selection of resilient rootstocks
3. improved disinfestation procedures
4. improved knowledge of Australian phylloxera ecology, and
5. improved knowledge of functional biodiversity and conservation biological control.

Background

Phylloxera remains a significant threat to the production of grapes and wine in Australia. Management of phylloxera is costly to government and the sector and relies on containment practices that include surveillance, diagnostics, quarantine and availability of resistant rootstocks. Wine Australia’s Phylloxera IPM project (DED 1701) produced new tools and knowledge that have considerably improved the sector’s ability to manage phylloxera, including an in-field diagnostics tool, improved disinfestation protocols, identification of new phylloxera genotypes and genotype-specific resistance in commercial rootstocks, and a comprehensive re-evaluation of biocontrol options. A next-phase research program is required to further improve these techniques and to consolidate new learnings into effective extension products.

Research approach

The project will employ an integrated pest management approach to:

• Provide more effective in-field surveillance and diagnostics for phylloxera, including new statistical models for improved zoning and rezoning and to establish a level of confidence in detecting an infestation at different levels of prevalence. The newly developed in-field LAMP assay will be used for large-scale phylloxera surveys. Research will determine the detection benefits of using root inspection/bucket traps and LAMP in field surveys and the ability of the assay to diagnose phylloxera outside peak activity e.g. winter.
• Assess selected commercial rootstocks for their susceptibility and resistance status to phylloxera. Commercial rootstocks developed by CSIRO (M5489, M5512 and the newer ‘C’ rootstocks) will be screened for resistance against at least five genotypes of phylloxera selected from diverse clades. The project will add to previous rootstock screening and the ongoing collaborative efforts with CSIRO in rootstock evaluation.
• Determine the risk posed to vineyards by leaf galling forms of the insect. Recent field surveys showed a considerable number of previously unknown gallicoles (leaf galling forms of phylloxera). Further research will conduct targeted surveys to establish the prevalence of gallicoles, characterise the genetic diversity and determine if some exist as both gallicoles and radicoles. The surveys will investigate whether particular rootstocks and vine varieties are more susceptible to gallicoles. The project will also revisit collected data and investigate interactions between phylloxera genotypes, rootstocks and environmental factors (such as soil type, aspect, temperature) and expand on this with further field-collected data. This could help with further rootstock breeding and selection.
• Update machinery disinfestation protocols. Lab-based studies will assess the effectiveness of disinfestation procedures under different hygiene situations that relate to cleaning of harvesters and will included phylloxera survival in soil clods and grapevine material following dry heat treatment. The propensity of insects to survive, develop and reproduce post-treatment will be assessed. The impact of overwintering temperatures on phylloxera survival and factors that induce and break dormancy will be determined.
• Determine the alcohol content for both red and white fermented products at which 100 per cent of a range of phylloxera genotypes are killed. This will add robustness to the disinfestation protocol for naturally fermented products, which currently specifies a number of hours of fermentation before grape products can be moved out of a Phylloxera Infested Zone (PIZ).
• Employ a conservation biocontrol approach to phylloxera by producing new knowledge of phylloxera predators. In conjunction with leaf galling surveys, vines will be inspected for potential phylloxera predators. Laboratory trials will be conducted using commercially available aphid predators to assess their impact on phylloxera.

In addition, the project will consolidate research outputs from this and previous projects into effective extension products and provide a pathway for sector uptake and adoption. Any regulatory implications for the sector (arising from findings in both new and previous work) will also be addressed.

Sector benefits

This project will capitalise on previous projects to enable the sector to be better prepared to manage phylloxera incursions into pest-free states and to protect pest-free vineyards in infested zones.