Maize

Insect pest risk

High riskModerate riskLow risk
Establishment pests
  • Paddock history of establishment pests.
  • High levels of retained stubble.
  • Dry conditions at crop establishment (increase attractiveness of seedlings to insect pests).
  • Slow crop growth at establishment makes plants more susceptible to damage (soil insects, thrips).
  • Seed dressings provide some protection against low to moderate numbers of establishment pests.
  • Increased sowing rate to compensate for known pest pressure.
  • Use of press wheels to limit soil insect access to seed and seedlings.
  • Weedy fallows (support pests prior to sowing).
Pre-sowing check of paddocks
Helicoverpa armigera
  • Large population carry-over from winter crops (e.g. chickpea, linseed, canola) or previous summer (northern region).
  • Large egg lay prior to tasselling results in large larvae damaging tassels and impact on crop fertilisation.
Use of non-selective pesticides for other pests in vegetative stages can flare helicoverpa.Maize varieties with husks extending 50-80 mm beyond the top of the cob and closing tightly around the silks restrict entry of larvae into the cob.

Pest incidence

PestCrop stage

Emergence

Vegetative

Silking/Tasselling

Grainfill

Black field earwigDamaging
WirewormsDamaging
CutwormsDamaging
Maize leafhoppersPresentDamaging
Maize thripsDamagingDamaging
LocustsDamagingDamaging
Whitegrubs (scarabs)DamagingDamaging
ArmywormDamagingDamaging
Swarming leaf beetlesDamagingDamaging
Red shouldered leaf beetlesPresentDamagingPresent
Green vegetable bugsPresentDamagingDamaging
Corn aphidsDamaging
HelicoverpaPresentDamagingDamaging
Two spotted mitesPresentDamaging
Red banded shield bugPresentDamagingDamaging
Yellow peach mothDamaging

 

PresentPresent in crop but gen­er­ally not dam­ag­ing
Dam­ag­ingCrop sus­cep­ti­ble to dam­age and loss

Key IPM considerations for maize

  • Economic damage is most likely to occur during establishment. Use germinating grain baits or direct soil sampling to provide information on risk.
  • Use hybrids with resistance to wallaby ear (a mycoplasma transmitted by maize leafhoppers)
  • Where helicoverpa larvae are present after mid March, the majority will enter diapause when they pupate. Pupae busting to prevent population carryover makes a valuable contribution to the area-wide management of H. armigera in the local area.
  • The use of NPV for helicoverpa control in maize is effective, and can be applied through overhead irrigation (centre pivot/lateral move).

Further information

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