Russian wheat aphid: declared pest

Page last updated: Wednesday, 13 June 2018 - 1:28pm

Russian wheat aphid is a major pest of wheat, barley and some grasses (Poaceae), which can cause significant yield losses.

Russian wheat aphid is not present in WA, but is widespread in South Australia, Victoria and New South Wales.

As a precaution, it is very important that growers, agronomists and consultants remain vigilant, and check cereal crops and grassy weeds for aphids and damage symptoms.

Impact

Russian wheat aphid is a serious pest of wheat and barley. Limited problems also have been noted in triticale, oats and rye. Russian wheat aphid is potentially a more severe pest than other aphids.

While aphid feeding damage generally results in yield losses of up to 10 per cent, in overseas crops Russian wheat aphid has caused yield losses of more than 80 per cent.

Unlike other aphids, Russian wheat aphids inject a toxin into susceptible crops, like wheat and barley, which can severely retard growth or under heavy infestations, kill the plant.

Aphid identification

  • Russian wheat aphids looks similar to other cereal aphids except it has two tiny tails at the rear end and lacks the usual excretion tubes or exhaust pipes on the top of the rear end of the body compared to other cereal aphids.

  • These pests are approximately 2 millimetres long, pale yellowish green with a fine waxy coating.

  • The antennae are short, as are the cone-shaped siphunculi (sometimes called cornicles).

Examine them closely using a hand lens or smartphone macro lens.

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Russian wheat aphid - note the two tails. Copyright: Frank Peairs Colorado State University Bugwood.org

Russian Wheat Aphid
Russian wheat aphid (Diuraphis noxia). Copyright: Frank Peairs, Colorado State University, Bugwood.org

Symptoms

See the webinar on recognising russian wheat aphid - available on YouTube or Podcast.

  • Symptoms could look like herbicide damage, thrips damage, mite damage or wheat streak damage.

  • Look for a noticeable loss of green colouration across the crop and, on closer inspection, white, yellow, purple or red streaking, leaf curling, stunted plant growth and loss of vigour.

  • Start plant inspections at the crop edge, where pests often colonise first, or where plants are under stress.

  • Look for aphid damage symptoms near the base of newly emerged leaves and inspect the leaves and leaf whorls of tillers.

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Russian wheat aphid damage on barley plant. Copyright: Howard F. Schwartz, Colorado State University, Bugwood.org

Russian Wheat Aphid wheat infestation
Diruaphis Noxia infesting wheat plants in the USA. Copyright: Texas AgriLife Extension Service

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Russian wheat aphid. Copyright: MA Nash

Declared pest category

Russian wheat aphid is declared to be a prohibited organism under section 12 of the Biosecurity and Agriculture Management Act 2007 (the Act) as Diuraphis (Diuraphis) noxia. 

Distribution

Russian wheat aphid is not present in WA, but in 2016 was found in South Australia, Victoria and New South Wales. Its preference for drier climates indicates it would thrive in the Western Australian wheatbelt. Up until 2016, Australia was the last major grain growing country in the world that was free of Russian wheat aphid.

This pest is widespread in southern Europe, Central Asia, the Middle East, North America and parts of Africa. It has been found in one region of the People's Republic of China for about 70 years, but has not spread to the major wheat-growing areas. It has recently been found in Chile and Argentina but has not yet become a serious pest.

Season of occurrence

Russian wheat aphid can be found throughout the year. Infestation of wheat and barley would start from the emergence of the crop in autumn and extend to crop maturity. During wet summers self-sown wheat and barley would serve as a 'green bridge'.

Reporting options

Report the absence or presence of suspect aphids or damage IMMEDIATELY via the options below:

On-farm biosecurity is important

Russian wheat aphid is spread by the movement of plant material, vehicles, machinery, equipment, livestock and wind. Adhere to good paddock hygiene measures to ensure any risk of spreading the pest is minimised, similar to managing for rusts.

  • Avoid driving vehicles through crops; and wash down vehicles frequently.
  • Limit the movement of people and equipment near the suspect crop.
  • Wash hands, and brush down clothes and boots that have been in contact with each crop.
  • Do not openly move or transport affected plant material between properties unless sending samples to your local DAFWA office.