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Bluegreen aphids

Consultant, Simon Mock (Clovercrest Consulting), reports that bluegreen aphids (Acyrthosiphon kondoi) have been found in lentil and lucerne crops near Kaniva, in SA. The level of feeding damage is minimal, although it will be important to monitor these crops closely over the coming weeks. Bluegreen aphids are normally found on the upper part of the plant, particularly the growing points.

Bluegreen aphids are a large species, measuring up to 3 mm long as adults. Both the winged and wingless forms are a matt bluish-green in colour. This species prefers to feed on legumes and is a common pest of medic and sub-clover pastures. They suck sap, causing yellowing and stunting of plants. A large amount of sugary solution (honeydew) is secreted by aphids when numbers are high. This can lead to black sooty mould which can reduce plant growth. Bluegreen aphids can transmit important plant viruses.

Natural enemies are a reliable form of control during the warmer days of spring. Insects which attack aphids include parasitoids (tiny wasps) and predators (ladybirds, hover flies and lacewings). These build up in crops along with the aphids and can reduce or contain aphid populations to below threshold levels in some seasons. However, they have less impact on heavy infestations of aphids.

For images of bluegreen aphids, click here.

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