Summary

Bluegreen aphids (BGA) can significantly damage lucerne and other crops through direct feeding and by spreading harmful plant viruses. The recent emergence of resistance to several insecticides – which form the main method by which to achieve control of BGA – presents a challenge for the lucerne, pasture seed and broader pasture industries in Australia. Through our preceding AgriFutures-funded project (project no. PRO-015519), we outlined short-term management tactics to help growers manage insecticide-resistant BGA. However, short-term recommendations cannot provide sustainable long-term solutions for insecticide-resistant pests. This project has three core objectives, which will collectively contribute to the development of long-term management guidelines aimed at mitigating the impacts of BGA. This project will: 1) gather important information on the spatial and temporal variation of insecticide resistance in the field; 2) generate baseline data on the biocontrol options for BGA. Using this information, we will 3) develop pest management guidelines and communicate our research findings to industry through multiple platforms (e.g., presentations, articles, videos, webinars) supported by Lucerne Australia’s extensive networks.

Program

Pasture Seeds

Research Organisation

Cesar Pty Ltd

Objective Summary

We will focus on three core objectives to improve the long-term management of BGA and mitigate the risk of further resistance evolution in this species. This has been shaped through discussions with key industry advisors and builds upon our previous AgriFutures Australia-funded project.

Resistance surveillance

In order to develop long-term management strategies for insecticide-resistant pests, knowledge of where resistance has spread and whether resistance is evolving to greater magnitudes (or to new chemicals) is essential; but this remains unknown for BGA. We will address these unknowns through spatial and temporal surveillance of insecticide resistance in BGA. Our surveillance will primarily target the lucerne production regions of SA – where resistant strains have become problematic – but will also include pasture seed and pasture production regions in other states where BGA control failures arise over the next 2 years.

Biocontrol

Greater use of alternative control methods, such as biocontrol, will lessen the risk of further insecticide resistance evolving in BGA. We will obtain data on the presence and diversity of parasitoid wasps that attack BGA in lucerne by leveraging aphid populations being collected as part of the resistance surveillance activities. We will also collect baseline data on the generalist predators that may attack BGA and other lucerne pests through (but limited) targeted surveys. This trapping is also likely to provide insights into other lucerne pests, such as crop mirids.

Management recommendations and Communications

Working closely with our industry advisory group, we will devise pest management guidelines for BGA that carefully considers other lucerne pests and the broader beneficial insect community. These recommendations, along with our research findings, will be communicated to industries through multiple platforms (e.g., presentations, articles, videos, field days) supported by Lucerne Australia’s extensive networks.