Elephant Weevil impact and control in vineyards – Stage 3: Regional survey and evaluation trials of Elephant Weevil (Orthorhinus cylindrirostris) in the Langhorne Creek grape growing area

Abstract

Improved knowledge of the behavior of elephant weevil in the Langhorne Creek region was acquired by this project which was a response to increasing concern among grape growers that the pest could become increasingly difficult to manage.

Summary

Grape growers expressed the view that if the lifecycle was better understood and if control measures were evaluated they would be in a stronger position to limit damage caused by larvae tunneling through cordons and adults chewing buds and other plant material. Methods used to help meet their needs included a survey to identify incidence and location of infestations and a 20 week student project to take a closer look at the local environment, seasonal behavior of elephant weevil and sites of attack.

Regional features that were found included higher concentrations of elephant weevil near then Bremer and Angus rivers and where there were high tree numbers at vineyard borders, as well as little evidence of weevil activity below 20 cm from ground level (which differs from findings in other regions). There was also a chance finding in the region of a parasitic wasp which could be having an effect on weevil populations.

The report tables results of assessment of devices to monitor and trap the pest, although it was concluded that visual monitoring and conventional control through cutting out affected wood and burning it remained effective.