Budworm activity in SE Australia: moths down, larvae up

Recent flights of budworm moths into SE Australia are mostly too late to pose a threat to crops, however, well developed larvae from earlier flights are commonly being found in sweep nets

Native budworm larva (Source: cesar).

 

Where have they been reported?

Large numbers of native budworm moths have been caught in pheromone traps within the Central, South West and Mallee regions of Victoria on October 11^th, and in the NSW Riverina between 14^th-17^th October. Using our predictive modelling tool (Darabug), we can advise that this flight will produce eggs that will reach the third instar stage by early November. By this stage most crops will have been either harvested or windrowed, hence this flight is unlikely to pose a threat to most crops.

Over the past few weeks, native budworm larvae have been recorded in sweep nets across the Victorian Wimmera, Mallee and NSW Riverina. In northern Victoria and southern NSW, 3^rd – 4^th instar larvae were the most common stage seen in dryland field peas and irrigated pulse crops, although final stage larvae have also been recorded.

On Twitter there have also been reports of budworm larvae sightings, at various stages, from within canola and pulse crops in the Victorian Wimmera, Mallee and the NSW Riverina (@LaunderRg, @DMAg_consultant, @timmy64c and @CKMonty).

About native budworm management

It is important to remember that native budworm are attacked by a large suite of natural enemies that can suppress grubs to below economically damaging levels. Parasitic wasps and flies, predatory shield and nabid bugs, brown lacewing larvae and ladybird beetles all attack native budworm within its various life stages.

For comprehensive information on native budworm, including their occurrence, lifecycle, management strategies, and threshold information, go to native budworm within the new PestNote series.

Our advice

Controlling native budworm in the final stages can be challenging; if needed, control should be directed at grubs <10 mm in length (3^rd – 4^th instar). Where native budworm caterpillars are being found in late stage canola or pulses, windrowing is an acknowledged means of disturbing the damage cycle, and opening up the canopy to other natural enemies such as birds.

Pheromone trap network

Since late August, we have jointly facilitated, with colleagues from SARDI, a network of 31 pheromone traps for native budworm moths across south-eastern Australia. The traps have revealed major differences in the timing and magnitude of the regional movement of moths, and allowed us to provide some indication of the timing of larval infestations. For those interested, we are happy to send a summary of the weekly results since late August from this trapping network.

We do thank everyone who assisted in maintaining and servicing pheromone traps, sending data and providing field advice to support this service. We hope the exercise has provided some real value in understanding and managing this pervasive pest.

 

Acknowledgements

This year’s pheromone trap program was undertaken with the support of the National Pest Information Service (NPIS), funded by GRDC. Adama Australia generously provided 4 automated traps for evaluation in a cropping environment. The many supporting individuals are listed below.

Institutional Support

• Prof Peter Gregg and Dr Alice del Socorro  – School of Environmental & Rural Science, University of New England (Armidale)
• Bill Kimber and Helen DeGraaf – SARDI (Adelaide)
• Alex Mills – Adama Australia Pty Ltd
• Rob Sonogan  – AGRIvision Consultants (Victorian Mallee)

Trap operators/facilitators

• Brad Bennett  – Consultant, AGRIvision Consultants (Victorian Mallee)
• Jim Cronin – Agronomist, Landmark (NSW Central West Slopes and Plains)
• Allan Edis – Agronomist, Landmark (NSW Riverina)
• Anna Fry - Trainee Agronomist, SHC (Victorian Mallee)
• Bill Gardner  – Agronomist and Grower (Victorian Wimmera)
• Shayn Healy – Agronomist, Crop Rite Pty Ltd (Victorian Mallee)
• George Hepburn  – Agronomist, Tylers Hardware & Rural Supplies (Victorian Wimmera)
• Neil Hives – IPM consultant central, southern and western Victoria (based in Central Victoria)
• Damian Jones – Irrigated Cropping Council (Victorian Mallee)
• Jake Leith – Agronomist, AGRIvision Consultants (Victorian Wimmera)
• Greg Toomey  – Agronomist, Landmark (Victorian Northern Country)
• David & Lachlan Trewick – Growers (Victorian Northern Country)
• David White – Agronomist, Delta Agribusiness (NSW Riverina)

 

Source of field reports

Matt Bissett – Agronomist, AGRIvision Consultants (Victorian Mallee)

James Challis – Agronomist, Rodwells (Victorian Mallee)

Damian Jones – Irrigated Cropping Council (Victorian Mallee)

Kent Wooding – Agronomist, AGRIvision Consultants (Victorian Mallee)