Pea Aphid

Pests of Field Crops in Southern Africa

PEA APHID

(Hemiptera/Homoptera: Aphididae)

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Text Box: A number of species of aphids have been recorded on peas, but the major one world-wide is Acyrthosiphon pisum. Although it does occur in sub-tropical areas, it is probably a less serious pest than in temperate climates, presumably because peas are predominantly grown in the winter season. It is a large (2.5-3.5 mm) aphid, pale green sometimes with a pinkish tinge, and has long, slender siphunculi and antennae. The colonies occur on the stems, young shoots and underside of young leaves, and react to disturbance by dropping off the plant. TOP

Text Box: Besides peas, these aphids have been recorded on lucerne, clover and ornamental sweet peas, and include among their hosts in other countries, several other leguminous plants. TOP

Text Box: The first irrigated crop of peas in about March is likely to be the only one that suffers from damage by this aphid. Lucerne crops may be quite heavily infested before the onslaught of the rains (October, November). Heavy infestations can result in distortion of the young leaves, and some yellowing. In other parts of the world, this species is reported to transmit some 25 different plant viruses. TOP

Text Box: As is the case with most aphids in the sub-tropics, the colonies are made up of females only, which produce live young. A single generation may take as little as a week, and winged individuals are only produced when the colonies become crowded. TOP

Text Box: Control of this pest is seldom warranted, but there are a large number of contact and systemic insecticides registered for use in peas, such as dimethoate, diazinon, malathion and mevinphos. TOP

Pea Aphids. (Photo: W Cranshaw, Colorado State Univ. Bugwood.org)