Identification of aphids in lupin crops

Page last updated: Friday, 25 May 2018 - 10:32am

Aphids reduce yields by direct feeding damage which causes flower and pod abortion and occassionally plant death in lupins. They transmit serious virus diseases which reduces yields and contaminate seed stocks. Some species of aphids are more difficult to control than others.

Species that attack lupins

All five species of aphids found on lupins in Western Australia are introduced. The three most common species are

  • cowpea aphid (Aphis craccivora)
  • bluegreen aphid (Acyrthosiphon kondoi)
  • green peach aphid (Myzus persicae)

Two other minor species sporadically recorded on lupin are:

  • leafcurl plum aphid (Brachycaudus helychrisi)
  • potato aphid (Macrosiphum euphorbiae)

This page pertains to the three common aphid species, which often occur together in a lupin paddock.

For information on aphid control and virus management refer to 'See also' section.

Cowpea aphid (CPA)

Cowpea aphids on a lupin plant
Cowpea aphids on Mandelup lupins. Photo courtesy of: Michael Macpherson (Imtrade).

 

Description

The cowpea aphid has a black body and black and white legs. It tends to arrive in lupin crops earlier than green peach or bluegreen aphids. They often form dense colonies on a single plant before moving on to surrounding plants and the contrast of their black bodies against green plants make them very visible. Heavy colonisation can cause rapid wilting.

Host range

The cowpea aphid's host range includes pasture medics, faba beans and tree lucerne.

Bluegreen aphid (BGA)

Bluegreen aphid on yellow  flowering bud of  lupin
Bluegreen aphid

Description

The bluegreen aphid is the largest of the three common species, measuring up to 3mm long. Both the winged and wingless forms are a matt bluish-green, similar in colour to the mature leaves of narrow-leaf lupins. The winged form has a light beige thorax.

Host range

This species prefers to feed on legumes and is a common pest of medic and sub-clover pastures. Large numbers of winged BGA fly from pastures to lupin crops later in the growing season. This species builds up to heavy colonies throughout the crop on susceptible lupin varieties.

Green peach aphid (GPA)

Green peach aphid on the underside of a canola leaf
Green peach aphid

Description

The green peach aphid tends to be shiny or waxy and ranges from yellow, through to green and pink. The yellowy-green forms are similar in colour to young unfurled lupin leaves. The winged forms have a dark patch on their backs.

GPA tends to be evenly distributed throughout the lupin crop, unlike cowpea aphid, which has a patchy distribution. The size of their colonies are usually smaller than those of BGA and CPA.

Host range

GPA colonises a wide host range and are often found on a variety of weeds including wild radish, wild turnip, doublegee and blackberry nightshade. When selecting a suitable chemical to use against an aphid infestation that is mainly GPA, the grower should be aware that some populations of this species have developed resistance to chemicals.

Aphid survival between growing seasons

The timing of first aphid arrival (migration) during the growing season largely depends on availability of green plant hosts during the preceding summer and autumn. Small numbers of aphids can survive the hot dry conditions experienced during summer if their host plants are available. Rainfall in late summer and early autumn encourages survival of aphid host plant material, leading to early aphid flights into crops soon after seeding.

Contact information

Author

Svetlana Micic