The fine structure of the trifoliate process of three species of Atherigona were studied. The outer surface of the lateral lobe of the process for the three species, A. bedfordi, A. hyalinipennis and A. secrecauda is covered with a dense mat of hairs. There are spine-like outgrowths on their inner surface referred to as “commasets” as well as some unusual sensilla on the rim of the lateral lobe and the section connecting the lobes to the stem. These structures showed inter-specific variation. The stem of the process is glabrous and granulate in A. bedfordi and A. secrecauda, but sparsely pilose in A. hyalinipennis.

This paper describes the results of extensive rearing of shootfly species of the genera Atherigona and Acritochaeta from cultivated and wild Gramineae in Andhra Pradesh, India. Nineteen fly species were recorded from 41 graminaceous species including cultivated sorghum. Atherigona soccata, an important pest of sorghums in the Old World tropics, was reared from 22 host plants. Only cultivated and wild species of sorghum were important as hosts of this pest species. It was observed that alternative host Gramineae were of minor importance in the ‘carryover’ of Atherigona soccata through the off season, but the irrigated sorghum grown for fodder could be an important source of flies.

In general, shootflies of a particular species usually favored one graminaceous host above others. The numerically dominant fly reared from wild Gramineae was Atherigona falcata, which was recorded on 17 hosts, including sorghum. Other common species in Gramineae were Atherigona pulla, Atherigona oryzae, Atherigona punctata and Atherigona atripalpis, all of which were also reared in very low numbers from sorghum. Five new species of Atherigona were reared; three of these will be described shortly.

The morphology and function of the trifoliate organ of five species are studied. Two examples are given where the ultrastructure of this organ assists the interpretation of speciation. The movement of the trifoliate organ during the courtship of Atherigona laevigata and its position during copulation is briefly described. A simple (A. seccata) and a complex (A. conigera) organ are described in detail, with emphasis on structure and function of the sensilla, and surface microsculpture. The A. hancocki-group organs are described and possible functions are suggested for these unusual structures. A distinct population is separated from the A. lineata species complex. A group of three species A. steeleae, A. secrecauda and A. matilei are confirmed to have a close, natural relationship.

The sorghum shootfly was first recorded as a pest in the central rainlands, causing losses of up to 25% in local varieties and 25–62.5% in introduced varieties. The pest has also been recorded in the Northern, Khartoum and Equatorial provinces.

In the Sudan, more than one species of Atherigona attack cereals, Atherigona soccata being the most dominant species. Sorghum plants attacked by the shootfly flower and ripen at different times.

A study of the biology of the shootfly showed that the incubation period of the egg was 2–3 days, the pupation period was 6–8 days and the duration from egg to adult was 17 days. The closer the eggs were laid to the leaf blade, the better the chances of the shootfly causing ‘dead-heart’ symptoms. The mortality of the first-instar larva was highest in the first 24 hr. The incidence of the shootfly coincided with rainfall and lower temperatures.

In a selection programme, Combine Kafir 60 had the lowest infestation level, compared to Sudan Grass, Abu Sabein and Feterita Gadarif varieties.