Aphids cause headaches late in the season

Aphids cause headaches for croppers late in the season


Cropping
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Aphids emerged in damaging numbers late in the growing season.

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Cabbage aphids infest the upper stems of a canola plant. Source - cesar.

Cabbage aphids infest the upper stems of a canola plant. Source - cesar.

PEST monitoring service cesar has reported aphids have caused issues in south-east Australian crops through the late spring period.

In its PestFacts newsletter, cesar said aphids were a particular problem through the Riverina in NSW and in parts of Victoria.

The aphids were noticed in canola in particular, with the cabbage and turnip aphids species in very high numbers.

Both species can be damaging to canola, especially prior to flowering ending.

With this in mind, cesar researcher Paul Umina said some growers had considered late season control options.

Other aphid species have also been sighted in damaging numbers in the Riverina.

The green peach aphid, a traditional enemy of emerging crops, was also seen in areas around Henty, however the PestFacts team said it generally caused less damage in the spring, instead it is regarded as being more of a threat in the autumn when crops are just coming up.

Dr Umina said damage was not confined to canola crops, with oat and corn aphid and the recently arrived Russian wheat aphid (RWA) all being spotted in cereal crops through Victoria and southern NSW.

However, he said for growers the window for economic losses from cereal aphids has passed as they are not regarded as problematic post grain fill.

In South Australia, where RWA was first spotted, researchers kept a close eye on numbers, but reported a drop in RWA densities after the crop went through the booting stage.

PestFacts attributed some of the success in keeping RWA numbers down to the use of seed treatments.

“Reports from growers and agronomists suggest that neonicotinoid seeding dressings have played a pivotal role in keeping RWA at bay this season,” the team said in its newsletter.

Numbers of aphids have also been brought down by beneficial predators, such as hoverfly larvae and parasitic wasps.

The story Aphids cause headaches late in the season first appeared on Farm Online.

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