PestFacts WA

Native budworm and lesser budworm caterpillars are causing damage to crops

Caterpillar activity reports

  • Northampton
  • Yuna
Native budworm caterpillar
Native budworm caterpillar. Photo courtesy of: DPIRD.

An agronomist has reported native budworm caterpillars causing severe damage to flowering lupin crops near Northampton. The high number of caterpillars are stripping the lupin plants of their leaves and flowers. The agronomist also reported native budworm caterpillars causing extensive damage to cereal crops in the area.

A lesser budworm caterpillar
A lesser budworm caterpillar. Photo courtesy of: Nick McKenna (Planfarm).

Nick McKenna (Planfarm) has reported finding what has been confirmed as lesser budworm damaging a wheat crop near Yuna.

Native budworm thresholds are based on avoiding damage to seed in maturing crops, which is usually when the caterpillars are at their most damaging. This year there has been the unusual situation in some areas of very high numbers of native budworm moths arriving earlier than usual coinciding with late developing crops. This has resulted in severe damage to the developing buds, flowers and leaves of some lupin and canola crops in the northern agricultural region. High numbers of what appears to be native budworm caterpillars, but could be lesser budworm, have also been reported causing extensive damage to cereal crops in the same area. As thresholds are based on maturing crops, growers must decide for themselves whether spraying for budworm is worthwhile to protect the buds, flowers and leaves of pulse and canola crops.

Given the high number of moths having migrated into crops early, it may be that spraying for budworm is required more than once this season given the length of season remaining and moths likely to continue to lay eggs into crops. This activity is reflected in cesar’s MothTrapVis map below.

A screenshot of cesar's MothTrapVis map showing native budworm moth trapping numbers from 23 July to 16 August 2019.
Screenshot of cesar's MothTrapVis map showing native budworm moth trapping numbers from 23 July to 16 August 2019.

Caterpillars of both species (native budworm and lesser budworm) will eat increasing quantities of plant material and seed as they grow. They will grow through six or seven stages or instars until reaching maturity (up to 40 mm long). The last two growth stages account for over 90% of their total plant material and seed consumption.

Native budworm (Helicoverpa puntigera) will attack a wide range of crops and pastures (field peas, lupins, canola, serradella and medics etc) and is a frequently occurring pest each year in WA, especially in eastern, northern and southern agricultural areas adjoining pastoral areas. 

Another less frequent and closely related pest is the lesser budworm (Heliothis punctifera), also a native species, that will attack the same crops but is also known to additionally feed on cereal crops.

There has been a number of reports this year of what appears to be native budworm caterpillars damaging cereal crops. However it is possible that there is a much higher occurrence than usual of the lesser budworm this year.

The feeding habits of the lesser budworm may be different to the native budworm. In the past the lesser budworm has been observed commencing to chew into newly formed lupin pods on the flowering crop. It is not characteristic of native budworm to chew into lupin pods until caterpillars are greater than 15 mm long and the crop is much closer to maturity, around leaf drop and pod maturation. When native budworm caterpillars (of any size) feed on canola crops they only cause damage to pods late in the season when leaf drop has occurred and pods are maturing and changing colour. It is uncertain as to the timing when lesser budworm may start to chew on canola pods.

Pulse, cereal and canola growers in north and central areas are encouraged to monitor their crops for plant feeding damage and check caterpillar numbers using a sweep net or bashing plants into a container if they are too short to sweep. Serradella, lucerne, clover and annual medic seed crops should also be regularly checked for budworm caterpillars.

If you have found caterpillars that appear to be native budworm feeding on cereals, and would like confirmation of the species please send samples to:

Department of Primary Industries and Regional Development
75 York Road, Northam WA 6401, attention to Dusty Severtson.

For more information on distinguishing native budworm caterpillars from lesser budworm caterpillars refer to the 2019 PestFax Issue 14 article Native budworm moth numbers are high.

Native budworm moth trapping surveillance

  • Usual automated and manual trapping locations
Native budworm moth
Native budworm moth. Photo courtesy of: Alan Lord (DPIRD).

This week has seen the numbers of native budworm moth flights slowing in many areas.

The higher captures this week include; Cunderdin (109 moths), Kirwan (97), Kellerberrin (92), Southern Cross (87), Maya (83), Bindi Bindi (57), Walkaway (53) and Dowerin (47).

Results of this week's automated and manual trappings are available at the department’s Native budworm moth numbers 2019.

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


Pesticide options for the control of native budworm can be found in the department’s Winter/Spring Insecticide Spray Chart 2019.

Detailed information on this pest can be found at DPIRD’s:

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


Article authors: Alan Lord (DPIRD South Perth) and Dustin Severtson (DPIRD Northam).

Green peach aphids are causing some damage to canola crops

  • Kojonup
  • Cunderdin
  • Northam to Westdale
  • Boxwood Hill
Large patch of green peach aphid feeding damage in canola
Green peach aphid feeding damage in canola. Photo tweeted by: Alec Smith (Kojonup Agricultural Supplies).

Alec Smith (Kojonup Agricultural Supplies) reports that green peach aphids (GPA) have caused feeding damage to a canola crop near Kojonup resulting in dead patches. He noted that beneficial insects and aphid-infecting fungi were evident, but not enough to control the GPA numbers.

Dan Taylor (DKT Rural Agencies) reports finding consistently low numbers of GPA in every canola crop inspected at Cunderdin and other central agricultural areas.

Entomologist Dusty Severtson (DPIRD) has also found consistently low numbers of GPA on the underside of leaves in canola crops from Northam down through to Westdale.

Green peach aphids on underside of canola leaves
Green peach aphids. Photo tweeted by: James Bee (Elders).

James Bee (Elders) has found very high numbers of green peach aphids on young pre-bolting canola near Boxwood Hill. Dead patches were evident.

Monitor crops closely this season

Insect pests such as aphids and caterpillars favour warm and dry days and growers are reminded to monitor crops, especially now given the late developing crops.

If you do identify GPA in your crop, monitor and only spray if young pre-flowering crops are moisture stressed and/or have high numbers of GPA on the plant so the plant is unable to outgrow GPA feeding damage. Aphid activity will slow down if cold and wet weather conditions are experienced.

To limit the spread and curb the further evolution of resistance, it is critical that sulfoxaflor (Transform®) is used judiciously and as part of a sound insecticide resistance management strategy. For more information refer to GRDC’s Resistance Management Strategy for the Green Peach Aphid in Australia Grains.

Growers are asked to keep a close eye on establishing canola crops this year and to contact cesar on +61 (0)3 9349 4723 if aphids survive a Transform™ application.

For a list of insecticides registered for use on aphids see the department’s 2019 winter/spring insecticide guide.

For more information on identifying and managing canola aphids refer to the DPIRD’s;

For more information on aphids contact Dustin Severtson, Development Officer, Northam on +61 (0)8 9690 2160 or Svetlana Micic, Research Officer, Albany on +61 (0)8 9892 8591 or Alan Lord, Technical Officer, South Perth on +61 (0)8 9368 3758.

Article author: Dustin Severtson (DPIRD Northam).

Canola sclerotinia update

  • Moonyoonooka
  • Moora
  • Northam
  • Woodanilling
  • Kendenup
  • Gibson
Sclerotinia infection in a canola leaf
Sclerotinia leaf infection. Photo courtesy of: Ciara Beard (DPIRD).

Plant pathologist Ciara Beard (DPIRD) reports finding sclerotinia leaf infection in a 44Y27 (RR) canola crop near Moonyoonooka this week. The crop was sown in late April and came up in early May as it is in a part of the paddock where the soil is always moist. It came up before the June break. The crop is patchy with different growth stages but the most advanced plants are at end of flowering/pod fill and these are showing leaf symptoms. The good canopy cover and density of the plants plus ongoing moisture is favourable for sclerotinia in this paddock but this is not typical of what most canola growers crops are like in the region this year. Ciara says most of the canola crops she has visited this season emerged after the June 7th break and only started flowering in the last two weeks. At this point in time most of the crops she has seen are not likely to have the canopy cover and density to favour sclerotinia infection.

Variable growth stages displayed in crop with canola plants that germinated in May (background) alongside canola plants that emerged in June (front).
Variable growth stages in crop with more advanced canola plants that germinated in May (background) alongside younger canola plants that emerged in June (front). Photo courtesy of: Ciara Beard (DPIRD).

DPIRD recommends growers use the SclerotiniaCM app to assist in determining the likely value of applying a fungicide application this season on their specific paddock.

Ciara has trials in at a number of locations in the Geraldton Port Zone this season to determine the value or otherwise of fungicide application for protecting canola crops from sclerotinia this season.

Plant pathologist Jean Galloway (DPIRD) reports that apothecia are present at Moora, Northam, Woodanilling, Kendenup and Gibson. In a trial at Northam, sclerotes produced last year and those produced during the 2017 season have produced apothecia.

Jean suggests that growers consider the risk of infection from paddocks sown to canola in 2017 and 2018.

For fungicide information visit DPIRD’s Registered foliar fungicides for canola in Western Australia page.

For more information on sclerotinia and managing the disease refer to DPIRD’s;

For more information on sclerotinia contact plant pathologists Ciara Beard, Geraldton on +61 (0)8 9956 8504 or Ravjit Khangura, South Perth on +61 (0)8 9368 3374 or Andrea Hills, Esperance on +61 (0)8 9083 1144.


Article authors: Ciara Beard (DPIRD Geraldton), Jean Galloway (DPIRD Northam) and Cindy Webster (DPIRD Narrogin).

Article input by: Ciara Beard (DPIRD Geraldton), Jean Galloway (DPIRD Northam) and Art Diggle (DPIRD South Perth).