sustainability through science & innovation

Oat aphids

More reports have come in from various locations in southern New South Wales and Victoria of oat aphid (Rhopalosiphum padi) problems. Agronomist, Mick Duncan (Northern Agriculture P/L), also reports high levels of aphids around Tamworth, in northern New South Wales. Mick says barley crops have seen particularly high aphid numbers. Spraying for oat aphid feeding damage is considered worthwhile if 50% of tillers have >15 aphids. Trials in Western Australia have shown that at this density (when crops are expected to yield 3 t/ha or more), feeding damage may cause reductions in yields by up to 10% and also reduce seed size.

The recent dry weather conditions experienced across most regions can confound aphid damage. Given the high prices for grain expected this season, many agronomists have decided that spraying is worthwhile. Unfortunately, late application of insecticides in situations where aphids have been at damaging levels for some time, or when applied to crops with advanced growth stages, will have less impact.

For images of oat aphids, click here. For further information, refer to earlier editions of PestFacts.

PestFacts is supported by