The leaf miner, Liriomyza trifolii burgess (Diptera: agromyzidae), a serious insect pest of faba bean (Vicia faba L.) in the Sudan. 1. Identification of the pest, natural enemies and abundance
1997
Sharaf El-Din, N. | Kannan, H. | Babiker, A. | Weigand, S. | Saxena, M.C.
Traditionally, faba bean (Vicia faba L.) is grown in the northerm part of the Sudan (16-22N). It was seriously damaged by the leaf miner, Liriomyza trifolii burgess, which was reported for the first time in the country when its production was extended to south of Khartoum (13-15N) in the mid-eighties, for reasons of land scarcity and high cost of production in the north. Accordingly, some basic studies were conducted to investigate the identity of the pest, the relative abundance throughout the cropping season, host plants and parasitism. Two leaf miner species, L. trifolli burgess, and Tropicomuia vigneae seguy were identified the former is the dominant species and identified on 12 plant species, while the latter was identified only from Dolichos lablab. Two species of the leaf miner parasitoids, Chrysonotomyia formosa westwood and hemiptarsenus semialbicalva girault were identified from leaf miners infesting a number of host plants, the former being the dominat species. The relative abundance of L. trifolli and its parasitoids were studied in unsprayed faba bean fields during November - February, 1987/88, with peak infestations in late December-early January. Parasitism level reached about 25 in late January-ealry February but levels as high as 60 were also recorded. Leaf miner adult flight activity was compared with the incidence and abundance of the pest on the faba bean crop. Biological studies revealed a high percentage of incomplete development of prepupae and pupae because of death or diapause, although no clear evidence of diapause was obtained. The importance of the high parasitism recorded, its practical implications and the need to maintain and enhance the role of the natural enemies is discussed and emphasized
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