Ophiomyia strigalis Spencer, 1963
This species is an example of potentially beneficial agromyzid species for they feed on Striga (Scrophulariaceae), a plant parasitizing culture plants, mainly cereals.
IMPORTANT CHARACTERS
Adults
Wing length: 1.9 - 2.3 mm.
Vibrissal fasciculus in males lacking (Oph strigalis head Sp.pct).
Male terminalia
Genitalia relatively characteristic (Oph strigalis aedeagus.pct).
Immature stages
Posterior spiracles of larvae with 5-6 bulbs.
Cephalopharyngeal skeleton quite normal, apparently with only two strongly alternating mouth hooks (Spencer, 1964).
BIONOMICS
External stem and root miner. The eggs are laid into the leaf axils at or just above ground level. The hatching larvae mine down into the roots. For pupation, they turn back and pupate within the host plant near the ground level (Davidson, 1963).
HOST PLANTS
Various species of the genus of parasitic weeds Striga (Scrophulariaceae). The host plants of Striga species are mainly cereals but also some other cultivated crops.
DISTRIBUTION
East Africa: known from Tanzania, Uganda, Kenya.
ECONOMIC IMPORTANCE
O. strigalis is apparently one of the commonest phytophagous insect on Striga (Davidson, 1963). Mining activity of the larvae cause rotting of the respective root area, probably due to secondary infections. However, since the agromyzids mainly infest mature plants, the impact for flower and seed production of the host plant is limited (Greathead and Milner, 1971).