Grains Research and Development

Date: 04.05.2015

Merging precision ag and slug control

Author: Alistair Lawson

An emerging sunflower crop affected by slugs

Sunflowers planted in October last year as part of the High Rainfall Zone (HRZ) Regional Cropping Solutions Network (RCSN) Fast Track project. On the left side of the image is slug bait applied at sowing and on the right is slug bait applied five days after sowing which resulted in reduced plant numbers. PHOTO: Michael Nash

The headaches that are slugs are an all-too-familiar problem for growers in the high rainfall zone (HRZ) of south-eastern Australia – something that has been recognised by the Grains Research and Development Corporation (GRDC) and the High Rainfall Zone (HRZ) Regional Cropping Solutions Network (RCSN).

While burning and cultivating stubble might be effective control methods for the slimy pest, the advent of no-till and zero-till cropping means growers’ options have been reduced to baiting. With that in mind, Compass Agribusiness Management - with the help of South Australian Research & Development Institute senior researcher, entomology Michael Nash, and the Victorian No Till Farmers Association (VNTFA) - have been engaged by the GRDC to undertake a HRZ RCSN Fast Track project investigating whether it is possible to get better slug bait efficacy using precision agriculture.

The project began in May last year with canola sown using a discseeder on 380-millimetre row spacing with two-centimetre accuracy. A day later, the same discseeder and configurations were used to place different treatments of slug bait on top of the crop rows.

Compass Agribusiness consultant Tim Pilkington says they found it hard to get accurate bait placement in their first attempt.

“We found even with RTK 2cm auto steer and using the same machine for both sowing and baiting the slight inaccuracies of each pass meant that we weren’t able to achieve the exact placement we were hoping for,” he said. “We also had issues with preventing the airflow in the seeder blowing the lighter baits off target and stubble impeding the bait placement making it harder for slugs to find the baits.”

But all was not lost and after a period of refining their planning and engineering, the team had another go in late-September when they sowed a sunflower crop. Mr Pilkington says he was pleased with early results.

“We used a precision planter to sow the sunflowers, which had boxes on the back for the application of granular insecticide, which are used in corn crops,” he said. “We used that to apply the slug bait directly above the crop row at seeding.

“We were able to guarantee accuracy of bait placement because it was applied in the same pass at seeding. We achieved good accuracy for bait placement with it all in a 10cm band above the crop row.”

Mr Pilkington believes the application at sowing made a huge difference to bait placement accuracy and the residue managers on the precision planter helped with putting baits onto clear ground for the slugs to find.

“The residue managers were clearing a path about 15cm wide, which means all the baits sat up on top of the row and weren’t obstructed by straw, so I was very happy with that application,” he said.

The trial is continuing in 2015 on another canola crop.

The key message to come out of current research is despite the product used or how it is applied, timing and rate are critical. Bait must be applied at sowing to protect germinating seed.

Another GRDC investment is researching novel methods to protect germinating cereal seed from slugs.

Additionally as a value added activity, in 2015 Southern Farming Systems will conduct a small, targeted GRDC project in conjunction with the VNTFA trial to explore at practicalities of using unmanned aerial vehicle (UAV) technology to monitor canola establishment and slug damage at the critical early stages of crop development.

This monitoring technique could potentially provide a cost effective means of crop monitoring to help guide pest management, identifying areas across the paddock that may require additional bait as plant numbers are reduced by slugs. One possible outcome is the opportunity for growers to use variable rate bait application, thereby improving the cost effectiveness of baiting.

More information:

Tim Pilkington, 0447 048 861, tim@compassagri.com

Michael Nash, 08 8303 9537, michael.nash@sa.gov.au

GRDC Project Code SAM00001, SFS00030

Region South