Advance Agriculture technical arable representative Andrea Fox set the traps in wheat and barley crops on four properties in Southland and South Otago.
The results were expected this week and would be available on www.aphidchat.com, Miss Fox said.
Generally, cereal crops sown in autumn in Otago and Southland avoided any of the virus spread by aphids due to cold conditions reducing any likelihood of an infestation of the pest.
However, a milder and drier than usual autumn might have increased aphid numbers, she said.
However, the efficacy of the insecticide coating would decline as the cereal crops grew in the next fortnight.
If aphids were present, growers could spray insecticide to protect their crop against the pest.
Foundation for Arable Research senior field officer Ben Harvey said the virus from aphids stunted the growth of a plant.
Aphid infestations could lead to yield losses of up to 10% but a bad season was rare.
If growers were considering applying an insecticide to control aphids this autumn, they should choose one which was gentle on beneficial insects, such as hoverflies, ladybirds and parasitic wasps, which assisted in reducing numbers of the pest, Mr Harvey said.
Aphids did not like strong wind and heavy rain so if a southerly front was forecast, growers might delay spraying an insecticide to see how the colder weather impacted pest numbers.
Growers could inspect their crops for aphids before spraying an insecticide but the pest had been known to live in the soil.
