In this article, VegNET Regional Development Officer Zara Hall investigates how the vegetable industry in south-east Queensland responded to a major production challenge posed by diamondback moth. Diamondback moth is a highly destructive pest that affects vegetable and canola crops across the country.

Diamondback moth represents a major production challenge for all brassica vegetable and canola growers across Australia. In the Lockyer Valley, diamondback moth management has proven increasingly challenging in recent years with growers reporting poor performance for several key Integrated Pest Management (IPM)-compatible insecticides registered in brassicas.

Testing by Greg Baker’s team at the South Australian Research and Development Institute – funded through CropLife Australia – has validated growers’ concerns, with results showing elevated resistance in diamondback moth to almost all pesticides registered in brassicas at levels that could affect field performance.

In response to a major production challenge, growers and industry led a number of complementary initiatives to manage diamondback moth, including development of an insecticide resistance management strategy and training sessions focused on utilising beneficial insects in cropping systems and latest spray technology.

Taking action

A pivotal step in implementing new practices for diamondback moth management was the formation of a Diamondback Moth Management Committee, facilitated by Lockyer Valley Growers Inc. President Michael Sippel and Chris Rutland from Nutrien Ag Solutions. One of the first strategies to be developed by the committee was the Insecticide Resistance Management Strategy, which focused on preserving natural enemies and use of IPM compatible sprays, such as Bts, in an area wide approach to pest management.

Spray technology was another training initiative led by industry. Troy Parchert from Creekside Fresh hosted a dye night, facilitated by Leesa Beling from Nutrien Ag Solutions with guest presenters Matt Moyle from Nufarm and Department of Agriculture and Fisheries, Queensland (DAF, QLD) Senior Extension Officer Clinton McGrath. This involved a hands-on session looking at boom spray calibration and fluorescing dye trials to demonstrate the impact of water volumes, use of adjuvants and nozzle selection on spray performance.

Creekside Fresh hosted a dye demonstration night, which focused on the impact of various water volumes, use of adjuvants and nozzle selection on spray performance.

Industry R&D

The region held a number of research and development initiatives that focused on diamondback moth. Jessica Page and Paul Horne from IPM Technologies and Lara Senior from DAF, QLD visited growers to discuss integrated pest management and share research findings from the strategic levy investment Impact of Pesticides on Beneficial Arthropods (VG16067).

John Duff’s team at DAF, QLD demonstrated innovative monitoring and management options for diamondback moth, while Matt Crust from Crust farms assisted University of Queensland PhD candidate Jessa Thurman to conduct on-farm trials investigating flowering border rows as a nectar source for Diadegma to increase in-field parasitism.

Monitoring and evaluation conducted by myself and Clinton McGrath – on behalf of CropLife Australia – indicated that most growers were able to effectively manage diamondback moth in the 2019 season. However to achieve effective control, growers had to change their management strategies to include more Bts sprays and utilise beneficial insects.

Find out more

Please contact VegNET Lockyer Valley RDO Zara Hall on 0456 956 340 or email ido@lockyervalleygrowers.com.au.

VegNET – Lockyer Valley is a strategic levy investment under the Hort Innovation Vegetable Fund.

This project has been funded by Hort Innovation using the vegetable research and development levy and contributions from the Australian Government.

Project Number: VG19010

Cover image: Justin Vanstone from Vanstone Produce discusses the Diamondback Moth Insecticide Resistance Management Strategy with students from UQ’s Gatton campus and Clinton McGrath from DAF, QLD.

VegNET RDO Zara Hall.

Resources and further information

Below is a list of online resources about diamondback moth and its management:

• Lockyer Valley Growers newsletter.
• Guide: Pesticide impact table for brassicas.
• IPM resources: Getting the most out of Bt sprays.
• Video: Gatton Research Station Diamondback Moth Management – Demonstration Trial.
• Video: Paul Windolf – Diadegma and Movento® for Integrated Diamondback Moth Management in Broccoli.

This article features in the spring 2020 edition of Vegetables Australia. Click here to read the full publication.