Using pitfall traps to detect pests
Growers are urged to observe their emerging crops and pastures for pest activity, particularly insecticide resistant redlegged earth mite (RLEM) populations and pests which may have survived typically used rates of insecticide, such as weevils, beetles, earwigs and balaustium and bryobia mites.
Some pests are frustratingly difficult to find because they are tiny, camouflaged and often active at night. This is especially true with weevils such as desiantha weevil, vegetable weevil and the new Dongara weevil species.
Pests can go unnoticed before they build up to damaging populations. While many can be found by inspecting the base of plants, in the soil and under stubble, some are more elusive. Those that attack plant roots or only emerge at night, such as vegetable weevils, are particularly challenging to detect.
A manual pitfall trap placed in the ground is one method to assess pests that may be difficult to find in low numbers, or during the day. A simple cup with a small amount of water can be placed into the soil within the paddock, left overnight and checked the next day. For more information on how to monitor early season pests, including how to set up a pitfall trap, see DPIRD’s How to monitor for early season pests YouTube video.
Remote imaging pitfall trap surveillance
As part of a GRDC co-investment called the National Grains Diagnostics and Surveillance Initiative (NGDSI), DPIRD has developed, in collaboration with Quisitive, a remotely imaging pitfall trap. These can trap ground dwelling pests such as weevils at any time, image them at high resolution, which can then be viewed and identified remotely from a computer anywhere.
So far in 2024, DPIRD researchers have installed remotely monitored pitfall traps to provide near real time identification of pest threats in 17 paddocks located in the northern, central and southern grain regions.
Pitfall traps at Brookton are being monitored to observe actual hatch dates of RLEM in comparison to the predicted hatching date. Pitfall traps near Albany are being monitored for Desiantha weevils, and pitfall traps near Nangetty and Mingenew are being monitored for Dongara weevils.
Pitfall trap findings will be regularly shared via the PestFacts WA newsletter.
Further information
You can request or confirm identification of potential broadacre insect pests by emailing the PestFacts WA team at pestfactswa@dpird.wa.gov.au or by contacting one of the following DPIRD Research Scientists Svetlana Micic in Albany on +61 (0)8 9892 859, Andrew Phillips in Geraldton on +61 8 9956 8567 or Dusty Severtson in Northam on +61 8 9690 2160.
Article author: Bec Severtson (DPIRD Northam).