Overview
This report presents Western Australian data on garden weevil (Phlyctinus callosus) incidence, damage and control. Adult feeding can kill newly planted vines and, the report states, reduce mature vine yields by up to 70%. Across seven vineyards, treated yields ranged from about 80% to 178% of untreated yields, so treatment was not always justified. Mid-row cover species were not related to weevil numbers. Biocontrol and pheromones were identified as priorities but not tested. At the time of publication, only three synthetic insecticides were available; the report recommended using them only where monitoring, including a canopy damage score, showed justified pressure. Sticky polybutene trunk bands were the most reliable non-chemical option, while fibre bands, kaolin clay and grease gave inconsistent or impractical results.
Garden weevil is one of the key insect pests of grapevines in Western Australian vineyards. It is also a pest of concern in some winegrape areas of Tasmania, South Australia and Victoria. Insecticides have been relied upon for protecting vines from garden weevil. The products available have limitations in terms of their selectivity and time of application to avoid residues in wine. This project investigated a number of aspects in relation to the sustainable management of garden weevil in grapevines to reduce the reliance on insecticides for control.
The project developed a set of recommended steps that vignerons could use to assess any new management aspects they considered could reduce populations of garden weevils.
A web site was established at the Department of Agriculture and Food Western Australia (DAFWA) internet address whereby aspects of garden weevil could be posted for public access.
A prototype canopy damage scoring system was developed to help vignerons quantify the abundance of garden weevil through feeding effects. This system was examined further to determine whether it could be used to define an economic injury level for vignerons to decide whether intervention was justified to prevent vines suffering economic loss. Results obtained showed that the system was of limited value in some situations because yield level was not always related to the damage score. However the system was considered to be an improvement compared to the previous trunk band based monitoring system in being more flexible and less time consuming to allow monitoring across a vineyard. It also meant it was more likely that hot spots of weevil infestation would be identified.
Abstract
This project investigated a number of aspects in relation to the sustainable management of garden weevil in grapevines.
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