Developing a threat-specific contingency plan for the exotic pest angular leaf scorch

Summary

Objectives

To validate the efficacy of drastic pruning as an eradication strategy for angular leaf scorch (ALS). A diagnostic protocol for the disease will also be developed for national endorsement by the Subcommittee on Plant Health Diagnostic Standards (SPHDS).

Background

The Viticulture Industry Biosecurity Plan (IBP) categorises the risk of exotic pests and diseases to the Australian industry and provides generic contingency plans through PLANTPLAN, which is a national set of incursion response guidelines for the plant sector. To ensure a rapid response in case of an incursion, it is crucial that the Australian wine industry has diagnostic capability for high-priority pests and diseases.

The current strategy for eradication of an exotic plant pathogen is based on the removal of whole affected plants, followed by burning and/or burial. However this strategy may have significant economic and social impacts on the industry and communities, particularly with respect to older, high-value premium vineyards. Research led by SARDI and in collaboration with DEPI Victoria through the CRC for National Plant Biosecurity developed and validated a drastic pruning strategy to eradicate the high-priority disease black rot from grapevines, without the need to completely remove vines. It is possible that a similar eradication strategy could be effective for other high-priority exotic diseases, such as angular leaf scorch and Rotbrenner, based on similarities in biology of the causal fungi.

Research approach

The project will establish a replicated field trial at the New York Agricultural Experimentation Station, Cornell University, USA to validate the efficacy of the drastic pruning protocol for eradication of ALS.  Symptoms will be recorded and samples collected in New York vineyards, to contribute to the development of a diagnostic protocol for the disease. The project will determine the susceptibility of Vitis vinifera cultivars typically grown in Australia and evaluate eradicant fungicides for angular leaf scorch using in vitro screening methods and inoculated potted or field vines.

Industry benefit

The project will provide a diagnostic capability for angular leaf scorch, a high priority pest identified in the Viticulture Industry Biosecurity Plan, by developing a protocol and a threat-specific contingency plan in case of an incursion of the disease into Australia. An important outcome of this project will be the enhancement of biosecurity research capability within the Australian wine industry.