IPM Guidelines For Grains

• Cowpea aphid: Colonies start in growing points
• Blue green aphid: infest growing tips first then move down stems to the crown as numbers build up

Risk of large infestations is higher if weather conditions are mild and hosts abundant.

• Heavily infested crops may show signs of wilting – more severe in water stressed crops
• Early colonisation by virus-infected aphids may result in yield losses from virus infections; bean yellow mosaic virus (BYMV) or cucumber mosaic virus (CMV).
• In lupins, direct feeding during flowering can cause flower abortion and poor pod set.

Look for aphids on stems and lower leaves

• reduce flowering
• reduce or prevent pod-set and pod-fill

Look for aphids on stems, lower leaves, buds and flowering heads

• Check at least 5 points regularly at different locations across a field and sample 20 plants at each point.
• Aphids are often first observed along the edges of crops.  Infestations may be patchy or in ‘hot spots’.
• Infestations can be reduced by heavy rain. Monitor again to determine if spray is still required
• Record the number of adult and juvenile aphids, beneficials including parasitised aphids (mummies), and the impact of infestation on crop. Repeat sampling provides information on whether the population is increasing (lots of juveniles), stable or declining (lots of adults and winged adults), and whether beneficials may be impacting on aphid populations.

• The presence of bloated aphids with pale gold/bronze sheen indicates parasitoid activity in the crop.
• Beneficials, including parasitoids and predators (ladybirds, hover flies and lacewings) will suppress low to moderate aphid populations but will not control heavy infestations. They also may not arrive early enough in the crop to prevent the build-up of aphids to above threshold.
• Beneficials can be important suppressors of aphid populations post-spray so determine impact of insecticides on beneficials before spraying (see Impact of pesticides on beneficials table).
• Reviewing aphid and beneficial densities over time may provide information on natural enemy impact.

• Control alternative hosts (wet autumn and spring promotes weed host growth – when they dry off aphids move into crops). Legume pasture species are also hosts.
• Sow crops early where possible to enable plants to flower before aphid numbers peak in the surrounding environment.
• Sow clean seed tested for cucumber mosaic virus (CMV) in lupins or pea seed-borne mosaic virus (PsbMV) in field peas.
• Cover of bare ground through rapid canopy development assists in deterring aphids (e.g. narrow rows with high seeding rates).
• High intensity rain during crop growth can suppress aphids.
• Research in WA shows that high levels of reflective stubble may deter aphids, especially in crops with wide row spacing.

• Lupins (WA) – if more than 30% of growing tips are infested with clusters of 30 or more aphids.
• Lupins (NSW) – treat at appearance of clusters on flowering plants
• Faba beans (Vic) – 10% of plants infested

• Systemic insecticides are the preferred chemical control (aphids often shelter in spray-inaccessible areas of the plant). However in very dry conditions translocation of chemicals may be impaired and insecticide will be less effective.
• If chemical control is required, consider aphid specific products (e.g. pirimicarb) to preserve beneficials. Refer to the impact of pesticides on beneficials table.
• If heavy rain and cool temperature are forecast consider delaying spray decisions until after rain and monitor again.
• Seed treatments and border spraying (autumn/early winter) when aphids begin to colonise crop edges may provide sufficient control.
• Controlling aphids to prevent virus is not usually an economic proposition as a small number of aphids can transmit virus and these populations could establish without being detected.
• Rotate chemicals to prevent resistance (see GPA insecticide resistance management strategy).

• Early colonisation by virus-infected aphids may result in yield losses from virus infections; bean yellow mosaic virus (BYMV) or cucumber mosaic virus (CMV).
• Control of aphids with aphid-specific insecticides will not impact on other pests/beneficials.
• Control of aphids with synthetic pyrethroids (SP) in seedling stage can flare SP-resistant mite populations.
• Use of SPs in early crop stages may flare lucerne flea and can also impact on predatory mites.

• An area wide attempt at controlling weeds can reduce aphid numbers in regions
• Good communication and sharing information with agronomists and other growers may provide initial indications of aphid presence.
• Industry publications provide up to date information about regional pest issues.