PestFacts WA

Native budworm monitoring and management in maturing crops

Caterpillars

• Gilgering
• Corrigin
• Kondinin
• Scaddan
• Wittenoom Hills

A native budworm caterpillar chewing into a lupin pod. Photo courtesy of: Christiaan Valentine (DPIRD).

Recently, the PestFacts WA team has received reports of approximately 5 native budworm caterpillars per 10 sweeps in a canola crop near Scaddan, one caterpillar per 10 sweeps in canola at Wittenoom Hills, and less than one caterpillar per 10 sweeps at Gilgering, Corrigin and Kondinin. Many crops have now been sprayed. 

It is likely that any native budworm moth flights occurring now will be too late to cause damage because the resultant immature caterpillars will be too small to cause damage to maturing crops.

However, in areas with later maturing crops, native budworm caterpillars can still cause damage to swathed canola. Swathing of canola crops usually dries out the pods quickly, making them unpalatable to the budworm grubs. If drying is delayed due to cool temperatures and damp weather, then green pods and soft seeds will continue to be susceptible to grub damage in swathed canola.

Locations where budworm moths were reported 3 to 4 weeks ago should be checked for native budworm caterpillars. This includes areas with later maturing pulse, oilseed, and pasture seed crops. Caterpillars hatching from eggs laid at this time will now be reaching a size of 5 mm, making them detectable in sweep nets.

Moth trapping surveillance update

Crops are nearing maturity, and as such, some of the volunteers who have been trapping native budworm have taken down their traps. Of the remaining traps, the largest numbers of native budworm moths caught in pheromone traps this week were reported at Cuballing (94 moths), Southern Cross (74), Cadoux (31), Varley (30) and Kellerberrin (19).

This surveillance is being conducted as part of the IPMforGrains project, which is delivered by the National Pest Information Network (Cesar Australia, DPIRD, QDAF, NSW DPI and SARDI). This initiative is a GRDC investment and includes in-kind contribution from all project partner organisations. 

A mapped view of the native budworm trap captures is available at Cesar Australia’s MothTrapVisWA page. Viewers need to select the desired trapping date range.

More results of this week's trappings are available for viewing at the department’s native budworm moth numbers 2023 page.

Management

Growers who may be contemplating spraying maturing canola, lupins and field peas should be mindful of chemical withholding periods and to check chemical labels before spraying. Minimum times required between the spray application date and harvest or windrowing crops can vary from 0 to 28 days (see Table 1).

Pesticide options for the control of native budworm can be found in DPIRD’s 2023 Winter Spring Insecticide Guide.

Growers and agronomists should be aware that the active ingredient cyantraniliprole is now registered for use on native budworm and diamondback moth on canola.

More information

Detailed information on this pest can be found at the department’s management and economic thresholds for native budworm.

To read about earlier native budworm activity this season, refer to the 2023 PestFacts WA Issue 17 article native budworm caterpillar update and Issue 9 article native budworm are active early.

For more information contact Technical Officer Alan Lord in South Perth on +61 (0)8 9368 3758 or +61 (0)409 689 468.

Article author: Alan Lord (DPIRD South Perth).