Native budworm moth trapping in Western Australia

Why is it important to trap and monitor native budworm?

Native budworm (Helicoverpa punctigera) is a major pest of pulse and canola crops in the south west of Western Australia (WA). The native budworm is indigenous to Australia and can develop large populations over extensive areas on native plants.

Native budworm caterpillars chewing into lupin pods. Photo courtesy of DPIRD.

These populations often migrate into agricultural regions in late winter and spring, causing damage to crops. Migratory flights are unpredictable, as moths may be carried hundreds of kilometres from breeding areas by high altitude air currents.

Collecting and communicating captured moth data via the PestFacts newsletter alerts, WA pulse and canola growers, of the likely risk of native budworm caterpillars being found in their crops in the weeks following the arrival of moths.

For more detail about the native budworm and its impact on crops refer to the department's Management and economic thresholds for native budworm.

How to install and maintain a native budworm trap

Native budworm pheremone trap. Photo courtesy of DPIRD.

It is easy to host a native budworm trap. Once the trap is set up, host growers or consultants need to check the trap weekly, count moth numbers and report the results weekly.

Moth trap installation instructions

You will require a star picket and a star picket driver or sledge hammer, pliers, the moth trap, mounting bracket and moth lure.

The moth trap should be positioned 10 to 20 m in from the crop edge of one of the more susceptible pulse crops, that is, field peas, lentils, faba bean, chickpea, lupin or canola (in the order of most susceptible to least).

Drive the star picket into the ground 20 to 30 cm or until it is firm.

Attach the moth trap to the mounting bracket with the wire provided (as shown in the photo above). Thread the wire through the hole at the end of the metal bracket and the two holes on the lid of the trap. Use pliers to squeeze the wire together around the trap lid holes.

Connect the mounting bracket to the star picket with the bolt and nut provided so that the bottom of the moth trap is level with the top of the crop.

Please note: for the trap to operate efficiently, is very important that the base of the trap is at canopy height.

Take one of the small orange/brown coloured pheromone rubber tube lures out of the plastic bag and place it into the green lure holder cage. Then insert the complete lure unit into the lid of the trap so that the pheromone lure is suspended over the opening to the trap.

Please note: Avoid touching the pheromone tubing with your fingers - the pheromone scent on your fingers can contaminate the lure and lessen its effectiveness. 

Place the plastic bag containing the small piece of pesticide strip in the base of the trap. This strip kills the moths and will last for about three months. Do not handle the pesticide strip with bare hands.

On Tuesday of each week inspect the trap for moths. Unclip the base of the trap and count the number of moths present. Empty the trap base of moths and reconnect the base.

If you wish to inspect the trap more often, then record the number of moths at each inspection date and the total number for the week.

Email the trap catch results to DPIRD Technical Officer Alan Lord. 

Replace the lure in the trap every four weeks with a new one. Keep your supply of lures fresh by placing them in a fridge/freezer or in some other cool place.

Discard the old lure in a bin. Do not throw into the crop or leave it in the holder.

Adjust the height of the moth trap as the crop grows. The base of the trap should be maintained at a height level to that of the crop, to obtain best trap results.

When you net your crop to check for grubs, fill in the section on the provided native budworm moth trap and net datasheet form. Also record details of any spraying for budworm.

Native budworm moth numbers captured in manual traps in 2023

Moth trap numbers are provided weekly by volunteer farmers, agronomists and some department staff within the WA grainbelt in 2023. The numbers provide an advanced warning to pulse and canola growers of the likely risk of budworm caterpillars being found in crops in the weeks following the arrival of moths.

Trapping results are sometimes discussed in further detail in the department's PestFacts newsletter.

Eggs laid by moths during August will take at least two weeks before they grow to a size of approximately 5mm and can be detected whilst sweep netting crops. It takes about seven weeks (average August temperatures) from the egg stage to reach the fully-grown caterpillar stage of about 40mm long.

The moth numbers below are provided as an early warning and not as a substitute for the essential sweep netting of crops to determine caterpillar numbers. Large numbers of moths do not always equate to large numbers of grubs. This is partially due to the effects of predators, parasites and weather.

Number of native budworm moths caught in a 7-day period by manual pheromone traps for the week ending on date listed in top row. (For a map view of trapping results refer to cesar's MothTrapVis map). The map allows users to monitor the weekly changes in moth flight numbers during the season by adjusting the trapping date range bar at the bottom of the map page.

*For a map view of  manual trapping results refer to cesar's MothTrapVis map.

Note: - indicates no data received, # indicates trap removed, ( ) numbers in brackets indicate trap catch days if not the standard seven days. N: north, S: south, E: east, W: west.

Do you want a native budworm trap this season?

Farmers or agronomists who would like to monitor budworm moth numbers in their crops can contact Technical Officer Alan Lord in South Perth on +61 (0)409 689 468 to request a trap.