Taxonomical and Biological Studies on Tetrany-Chid Mites of the Sudan (Acarina: Tetranychidae).

Abstract

This work was conducted in the Faculty of Agriculture at Shambat, to study the taxonomy and biology of tetranychid mites collected from different areas of the Sudan. These are: Bryobia uritacae Sayed, Porcupinychus abutiloni Anwarallah, Oligonychus partensis Banks, Tetranychus neocaledonicus Andre, Eutetranychus orientalis Klein and Eutetranychus sudanicus n.sp. The latter was considered as a new species. It was found to be a destructive pest to a wide range of host plants, mainly citrus. Biological studies were carried out for a whole year from October 1967 to 1968 to investigate the different biological aspects of this species. The life cycle of this pest passed from the egg to adult, through one larval and two nymphal stages. The duration of the development stages are affected by the climatic conditions as well as the fecundity of the females. During the course of this study, twenty seven generations of E. sudanicus were reared in Shambat area. About 74 per cent of these generations were reared in summer while approximately 21 per cent were reared during winter. Parthenogenesis usually takes place in this species but only males are produced.