sustainability through science & innovation

An action threshold calculator for Russian wheat aphid

Researchers from SARDI and cesar have developed a calculator to help crop advisors and growers decide if spraying for Russian wheat aphid (RWA, Diuraphis noxia) is economically justified.

This action threshold calculator considers dynamic factors including cost of control, cereal market price and aphid numbers.

It can be used between GS30 (start of stem elongation) and GS50 (start of head emergence), although monitoring is recommended at GS30 as early infestations of this aphid can prove the most impactful on potential yield.

The calculator

Prior to using the calculator it’s important that you read the following document - Russian wheat aphid action threshold calculator: instructions for use


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This action threshold calculator is the culmination of field trial data collection and analysis over two winter cropping seasons (2018-2019) in south eastern Australia.

Any feedback on the calculator can be sent to

Look out for a write up on our green bridge risk work

This project also included intensive sampling of Russian wheat aphid over spring – autumn in order to support development of a model to predict green bridge risk.

Understanding what green bridge conditions will support Russian wheat aphid populations can help researchers, advisors and growers predict if winter crops have a high of low likelihood of being infested by Russian wheat aphid during crop establishment.

For most grain growing regions (Tasmania has been observed to be a frequent exception), Russian wheat aphid populations are expected to grow within cultivated crops over the winter. They will then disperse during a spring migration into refuges to ‘over-summer’, and then re-disperse back into emerging crops during an autumn migration.

Keep an eye out for our next cesar News Russian wheat aphid article, which will explore the importance of the green bridge further and share our project findings.



The GRDC investment UOA1805-018RTX 'Russian wheat aphid risk assessment and regional thresholds’, investigated regional risk and management tactics for Russian wheat aphid (RWA). The project was led by the South Australian Research & Development Institute (SARDI) and undertaken in partnership with cesar over 2018-2020.

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