Notes on East African, Aphids IV-Aphids of Leguminous Crops

Abstract

One root-feeding and five leaf-and stemfeeding aphids are described here. Trifidaphis phaseoli (Pass.), a white globular aphid without siphunculi and with short legs and antennae, occurs on the roots of many dicotyledons in addition to Leginninostr and is sometimes a pest of potatoes. This aphid, like a number of other root-feeding Fordini, has the cauda and sub-anal plate placed dorsally and enclosed on three sides by the inverted U-shaped eighth tergite (Fig. N). Macrosiphuin nigrinectaria Theobald is known only from East Africa and occurs most commonly on cow pea, Cajanus indicus. This aphid differs most obviously from M. euphorbice (described in Part 11 of this series) by the completely black siphunculi and the short antennal hairs. Acyrthosiphon pisum (Harris), a large green aphid with a long green cauda and long slender green to dusky siphunculi without hexagonal reticulation at the apices, occurs on many legumes as does Aphis craccivora Koch, the vector of groundnut rosette. A. craccivora is not figured as it resembles A. gossypii (figured in Part II) except that craccivora is a shiny black aphid in life while the black forms of gossypii are dull. Therioaphis spp. are recorded from many countries (but not yet East Africa) as pests of legumes, particularly clovers, mostly under the name T. ononidis. It is not known how many of these ornate black and yellow or black and white aphids occur in Africa. The species figured here (Figs. H—L) is T.(Pterocallidium) maculatum (Buckton). Megoura vicke Buckton, a large bright-green aphid with jet black legs, long cauda and swollen siphunculi, is not recorded from East Africa but is common on Leguminosce in other parts of the world.