PestFacts WA

Cabbage, turnip and bluegreen aphids

Cabbage and turnip aphids

  • Grass Valley
  • Amelup
Cabbage aphids on canola
Cabbage aphids. Photo courtesy of: Dusty Severtson (DPIRD).

Entomologist Dusty Severtson (DPIRD) has recently found small numbers of cabbage aphids on the edge of a canola crop near Grass Valley. The crop was at the early flowering stage and a few isolated plants on the crop edge were infested.

Parasitised aphid mummies on a canola plant
Parasitised aphid mummies. Photo courtesy of: Dusty Severtson (DPIRD).

Dusty has also reported finding hot spots, mostly along crop edges, in late flowering canola crops near Amelup. Parasitised mummies were also present in one crop indicating beneficial insect activity. One crop in the area had a mixture of cabbage and turnip aphids on racemes.

Growers and consultants are advised to re-check canola crops for aphids, even if they have been previously sprayed, especially if the crop has experienced frost. They also need to check canola crops for fungal infections and parasitisation in aphids before deciding to invest in an insecticide spray. For more information see the department’s Know what beneficials look like in your crop.

Cabbage aphids form dense bluish grey colonies covered with fine whitish powder on flowering heads in spring. They also establish on crowns and under leaves in the vegetative phase. Infestations are usually as ‘edge effects’ or 'hotspots' in the paddock. The adult aphid is dull or greyish-green.

Cabbage aphids can feed on canola plants, particularly if warm daytime temperatures are experienced which favour aphid reproduction and feeding damage.

If more than 20% of plants are infested with colonies of cabbage or turnip aphids, control measures should be considered to avoid yield losses. The risk of economic yield losses to aphids is increased if canola crops are already under some degree of moisture stress or experience poor finishing rains.

Growers, consultants and other field operators that would like to know how close they are to the canola aphid threshold and where across crops this is occurring can download the new CropScout app. The app is designed to assist inspection of canola for aphids relative to the spray threshold and easily record and visualise results on a map. This field intelligence can then be used to optimise spray timing and, where possible, to target sprays to pest infestations across properties or within individual crops. For more information, see the department’s CropScout page.

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;

Bluegreen aphids

  • Borden
  • Amelup
Blue-green aphids
Bluegreen aphids on a lupin plant. Photo courtesy of: DPIRD.

Brent Pritchard (Farmanco) has found aphids likely to be bluegreen aphids starting to colonise lucerne seedlings in the Borden area. The crop is being monitored.

Entomologist Dusty Severtson (DPIRD) has found very high numbers of bluegreen aphids on lucerne at Amelup. They were found on the underside of leaves and were not noticeable unless plants were knocked onto a hand or container.

Bluegreen aphid adults grow up to 3 mm long, are oval shaped, with long legs and antennae. They have two large cornicles that extend beyond the base of the abdomen. Both the winged and wingless forms are a matte bluish-green colour. Nymphs are similar to adults but are smaller in size.

Bluegreen aphids are active during autumn and winter but are most prominent during spring.

Bluegreen aphids feed on the upper leaves, stems and terminal buds of host plants.

For more information refer to cesar’s Bluegreen aphid PestNote.


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

Article authors: Cindy Webster (DPIRD Narrogin), Dusty Severtson (DPIRD Northam), Alan Lord (DPIRD South Perth).

Native budworm


  • Yuna
  • Geraldton
  • Walkaway
  • Carnamah
  • Kirwan
  • Maya
  • Three Springs
  • Bindi Bindi
Native budworm caterpillar on wheat
Native budworm caterpillar on wheat. Photo courtesy of: Nick McKenna (Planfarm).

Nick McKenna (Planfarm) reports finding budworm caterpillars eating into the glumes of wheat at Carnamah.

Technical officer Joanne Walker (DPIRD) has found 14 native budworm caterpillars per 10 sweeps in a lupin crop near Geraldton. Another lupin crop  further south near Walkaway she surveyed had only one budworm caterpillar per 10 sweeps.

Ty Henning (TekAg) reports finding one native budworm caterpillar per 10 sweeps in a late flowering lupin crop near Kirwan.

Technical officer David Nicholson (DPIRD) used a sweep net to sample several lupin crops this week and found varying numbers of native budworm caterpillars. East of Maya he found 35 grubs per 10 sweeps, north-west of Three Springs 73 caterpillars per 10 sweeps and east of Yuna less than 1 caterpillar per 10 sweeps.

A farmer near Bindi Bindi reports finding 2 budworm caterpillars (5-10mm) per 10 sweeps in a canola crop.

There has been a significant number of reports of budworm-like caterpillars being found in cereal crops in the northern agricultural region this season. What has surprised department entomologists is that samples and good resolution images sent in have ruled out the lesser budworm (Heliothis punctifera), the corn earworm (Helicoverpa armigera), and armyworm with diagnostics pointing to the native budworm (Helicoverpa punctigera).

Native budworm are not known to feed on cereals and it had previously been thought that native budworm on cereals had originated from volunteer pulse or canola crops which then transferred onto the cereal plants, which may explain some the issue. There has been very high moth pressure in the north this year and earlier than usual which complicates the matter further.

A number of agronomists have reported that budworm caterpillars in cereals seem to be much higher in cereal crops sown into lupin or chickpea stubble, indicating that moths had perhaps laid eggs onto early volunteers which hatched into caterpillars and fed. Then when the volunteers were subsequently sprayed out, the caterpillars have moved onto the cereals. If this is not the case, then it would be interesting to know if lupin or chickpea stubble somehow attracted moths during their migration.

Growers are advised that spray thresholds developed for native budworm in pulse and canola crops should not be used for budworm in cereal crops.

Native budworm will attack a wide range of crops and pastures (pulses, lupins, canola, serradella and medics, etc.) especially in eastern, northern and south eastern agricultural areas adjoining pastoral areas. The feeding behaviour of native budworm caterpillars changes according to the type of crop the caterpillars are feeding upon. Field pea, chickpea, lentil and faba bean crops are very susceptible to all sizes of caterpillars during the formation and development of pods. Tiny caterpillars can enter emerging pods and damage developing seed or devour the entire contents of the pod.

Narrow-leafed lupin crops will not be damaged by native budworm until they are close to maturity and the pods are losing their green colouration, Canola is similar to narrow-leafed lupin in that pods only become attractive to caterpillars as the crop nears maturity and begins to hay-off.

Native budworm moth trapping surveillance

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

The native budworm moth trappers have recorded numbers dropping off in many locations. The larger native budworm flights recorded by budworm trappers this week include: Kirwan (79 moths), Badgingarra (53), Southern Cross (36), Bindi Bindi (28) and Dowerin (25).

Grower are still encouraged to monitor crops as the caterpillars that hatched from eggs laid by moths in some of the large moth flights three to four weeks ago will now become noticeable in crops.

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.

The trap numbers only provide an indication of the pests activity and cannot be relied upon for control decisions. Only the use of a sweep net to regularly check crops can give growers confidence in the levels of budworm present. Detailed information on this pest can be found at the department’s Management and economic thresholds for native budworm.


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

Previous budworm activity and management information is available 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 Dusty Severtson (DPIRD Northam).

Wheat disease update

Flag smut

  • Wongan Hills
Flag smut on wheat
Flag smut on wheat. Photo courtesy of: Sarah Collins (DPIRD).

Technical officer Tracey Mouritzen (DPIRD) has reported finding flag smut in a DPIRD trial near Wongan Hills. Wheat varieties Wyalkatchem and Mace were infected. The plants in the trial have mainly finished heading. Tebuconazole was applied to the trial on the 28 June and 21 August. The paddock was sown with canola in 2018 and cereals in 2017.

Wyalkatchem is rated as being susceptible to very susceptible (SVS) and Mace is susceptible (S) to flag smut.

Infected wheat plants leaves, leaf sheaths and occasionally stems have long grey-black streaks with powdery black spores (which rub off easily) on them.

During harvest, flag smut spores are distributed onto surface of seed or onto the soil. Spores of the fungus can survive in soil for up to seven years and can be moved to adjacent paddocks by wind, plant debris or equipment. Seed sown into contaminated soil is at risk of developing the disease.

Registered fungicide seed dressings are highly effective. In paddocks contaminated with flag smut, use clean fungicide-treated seed of resistant varieties the following season to reduce disease risk. Disease rating information for varieties can be checked in DPIRD’s 2019 wheat variety sowing guide for WA.

For more information refer to DPIRD’s Diagnosing flag smut of wheat and Smut and bunt diseases of cereal - biology, identification and management pages.

Powdery mildew

  • Gairdner
Powdery mildew on a wheat leaf
Powdery mildew on wheat. Photo courtesy of: Sarah Belli (DPIRD).

Development officer Sarah Belli (DPIRD) has reported finding powdery mildew in Scepter wheat near Gairdner. The plants were at milk development growth stage.

For more information on this disease refer to DPIRD’s


For more information on wheat disease contact Geoff Thomas, Plant Pathologist, South Perth on +61 (0)8 9368 326, Kithsiri Jayasena, Plant Pathologist, Albany on +61 (0)8 9892 8477,  Andrea Hills, Plant Pathologist, Esperance on +61 (0)8 9083 1144 or Ciara Beard, Plant Pathologist, Geraldton on +61 (0)8 9956 8504.


Article authors: Cindy Webster (DPIRD Narrogin), Geoff Thomas (DPIRD South Perth).