Winter cereals

Winter cereals include wheat, barley, oats, canary and triticale.

Insect pest risk

High risk Moderate risk Low risk
Soil insectsslugs and snails
  • Some crop rotations increase the likelihood of soil insects
    • cereal sown into a long term pasture phase;
    • high stubble loads;
    • above average rainfall over summer-autumn.
  • History of soil insects, slugs and snails
  • Summer volunteers and brassica weeds will increase slug and snail numbers
  • Cold, wet establishment conditions exposes crops to slugs and snails
  • Information on pest numbers prior to sowing from soil sampling, trapping and/or baiting will inform management.
  • Implementation of integrated slug management strategy (burning stubble, cultivation, baiting) where history of slugs.
  • Increased sowing rate to compensate for seedling loss caused by establishment pests.
 Slugs and snails are rare on sandy soils
Earth mites
  • Cereals adjacent to long term pastures may get mite movement into crop edges.
  • Dry or cool, wet conditions that slows crop growth increases crop susceptibility to damage.
  • History of high mite pressure.
Leaf curl mite populations (they transmit wheat streak mosaic virus) can be increased by grazing and mild wet summers. Seed dressings provide some protection, except under extreme pest pressure.
Aphids
Higher risk of barley yellow dwarf virus disease transmission by aphids in higher rainfall areas where grass weeds are present prior to sowing

Wet summer and autumn promotes survival of aphids on weed and volunteer hosts.

  • Wet autumn and spring promotes the growth of weed hosts (aphids move into crops as weed hosts dry off ).
  • Planting into standing stubble can deter aphids landing.
  • Use of seed dressings can reduce levels of virus transmission and delay aphid colonisation.
  • Use of SPs and OPs to control establishment pests can kill beneficial insects and increase the likelihood of aphid survival.
Low rainfall areas have a lower risk of BYDV infection.

High beneficial activity (not effective for management of virus transmission).

 

Armyworm
Large larvae present when the crop is at late ripening stage.
  • High beneficial insect activity (particularly parasitoids).
  • Rapid crop dry down.
No armyworm present at vegetative and grain filling stages.

Pest incidence

Pest Crop stage

Emergence

Vegetative

Flowering

Grainfill

Wireworms Damaging Present
Cutworm Damaging
Black headed cockchafer Damaging Present
Earth mites Damaging Present
Slugs, snails* Damaging
Brown wheat mite Damaging
Aphids Present Damaging Present Present
Armyworm Present Present Damaging
Helicoverpa armigera Damaging

 

Present Present in crop but gen­er­ally not dam­ag­ing
Dam­ag­ing Crop sus­cep­ti­ble to dam­age and loss.

* Snails are also a grain contaminant at harvest

Key IPM strategies for winter cereals

  • Where the risk of establishment pest incidence is low (e.g. earth mites) regular monitoring can be substituted for the prophylactic use of seed dressings.
  • Where establishment pests and aphid infestations are clearly a result of invasion from weed hosts around the field edges or neighbouring pasture – a border spray of the affected crop may be sufficient to control the infestation.

Insecticide choices

  • RLEM, BOM, and other mite species can occur in mixed populations. Determine species composition before making decisions as they have different susceptibilities to chemicals.
  • Establishment pests have differing susceptibilities to insecticides (SPs, OPs in particular). Be aware that the use of some pesticides may select for pests that are more tolerant.

Insecticide resistance

  • RLEM has been found to have high levels of resistance to synthetic pyrethroidssuch as bifenthrin and alpha-cypermethrin.
  • Helicoverpa armigera has historically had high resistance to pyrethroids and the inclusion of NPV is effective where mixed populations of armyworm and helicoverpa occur in maturing winter cereals.

Regional differences

Black headed cockchafers are not known to occur in winter cereals in WA.

Further information

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