Aphids

Aphids

Aphididae family

Aphids is a general term for a large number of insects from the Aphididae family.

Family: - Aphididae

Order: - Hemiptera

Description:

Adult

Colour - Black, browns and greens usually.

Body - Stout, soft bodied. Usually less than 2 mm long.

Legs - 6.

Wings - Winged and wingless forms.

Mouth Parts - Piercing stylet.

Nymphs

Biology:

Life Cycle:

They often survive harsh summer or winter conditions by shifting to protected locations or producing dormant resting forms or eggs that hatch when conditions improve.

Many species can reproduce without males or have two forms of reproduction - sexual and asexual.

Aphids can distinguish plant colour and are usually attracted to green and yellow. Pea aphids can also detect plant odours such as cut grass. Winged aphids appear to have a better sense of smell than their wingless counterparts.

Habitats:

Origin and History:

Distribution:

Significance:

In canola the main species causing economic damage are

Cabbage Aphid (Brevicoryne brassicae)

Turnip Aphid (Lipaphis erysimi)

Green Peach Aphid (Myzus persicae)

Blue Green Aphid (Acyrthosiphon kondoi)

and occasionally the Potato Aphid (Macrosiphum euphorbiae).

Aphids in Canola can build up to very quickly within 2 weeks of their first appearance. They are most damaging at from the budding to early pod development stages of Canola. In WA they rarely get to levels that cause economic loss. Trials indicate that most stems need to have 25 mm of aphids on them before it is worth spraying and this rarely occurs. Damage appears to be worse on water stressed crops.

Aphids in Canola may be identified on the following features.

Species	Abdomen Colour	Body length	Colony habit	Features
Blue Green Aphid	Waxy blue-green	2-3 mm	On growing tips.	Long pale legs with black tips. 2 long "exhaust pipes" on tail.
Cabbage Aphid	Greyish to dull mid-green	1.6-2.8 mm	Dense on tips of plants.	Coated with white mealy wax.
Green Peach Aphid	Waxy green, but varies from shining yellow to pink or orange red. Winged form has a black patch.	1.2-2.3 mm	Usually scattered light colonies. Often on lower leaves.
Potato Aphid	Light yellowish to pinkish green or bright green. Often with a darker green stripe down middle of the back	1.7-3.6 mm	Small colonies	Red eyes.
Turnip Aphid	Yellowish to olive-green, sometimes with dark bars.	1.4-2.4 mm	Dense on tips of plants.	Black legs. Small "exhaust pipes" on tail. Sometimes has a waxy dusting

Adapted from D. Eksteen, Agriculture WA

In cereals the main aphids causing damage are

Oat Aphid (Rhopalosiphum padi)

Corn Leaf Aphid (Rhopalosiphum maidis)

Rice Root Aphid.

See descriptions under Aphids; Cereal.

In Lupins the main aphids are

Green Peach Aphid (Myzus persicae)

Blue Green Aphid (Acyrthosiphon kondoi)

Cowpea Aphid (Aphis craccivora)

In Faba Beans the main aphids are

Green peach aphid (Myzus persicae)

Blue Green Aphid (Acyrthosiphon kondoi)

Cowpea Aphid (Aphis craccivora)

Pea Aphid (Acyrthosiphon pisum)

In pastures the main aphids are

Blue Green Aphid (Acyrthosiphon kondoi)

Cowpea Aphid (Aphis craccivora)

Spotted Alfalfa Aphid (Therioaphis trifolii)

Aphids damage plants directly by sucking the sap from the plant or indirectly by transmitting viruses or encouraging fungal growth on the 'honey dew' they excrete. Most aphids are quite specific to a particular plant or group of plants, and in some cases are only found on particular parts of the plant. Their ability to rapidly build up numbers make them difficult to control both biologically and chemically. Common symptoms of aphid attack are clusters of the aphids, mottling or wilting of leaves or fruit, or symptoms of viral infection.

Management and Control:

There are a number of insects that feed on aphids such as lady birds, lace wings and hover flies. Choosing an insecticide that doesn't harm these species helps maintain control for a longer time.

Related Species:

Similar Species:

References:

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 for more information.