International Journal of Pest Management (1999) 45, 35-40

J.M. Songa and J.K. Ampofo (1999)
Ecology of the bean stem maggot attacking dry bean (Phaseolus vulgaris L.) in the semiarid areas of eastern Kenya
International Journal of Pest Management 45 (1), 35-40
Abstract: Relative abundance and population dynamics of bean stem maggot (BSM) (Diptera: Agromyzidae) life stages and the relative abundance of species were investigated at two sites in Kenya: Kiboko (900 m) and Katumani (1600 m), during two cropping seasons: (October 1995-January 1996) and (March-July 1996). This was done by weekly random sampling of 20 plants per plot, for up to 7 weeks, from each of four plots established at weekly intervals. Numbers ofeach life stage per sample were counted. In both sites and seasons, numbers of BSM ovipositor punctures in leaves, and numbers of eggs, larvae and pupae were higher on the late than on the early sown crop. Numbers of leaf punctures and eggs increased and peaked at 5- 6 weeks after plant emergence then declined thereafter. Larval and pupal numbers increased as the season progressed. Two BSM species, Ophiomyia phaseoli Tryon and O. spencerella Greathead, infested bean plants in both sites. O. phaseoli was the dominant species at Kiboko, whereas O. spencerella was the major species at Katumani. A reversal of BSM species dominance was observed at Katumani during the October 1995 - January 1996 cropping season. BSM populations appeared higher during dry higher temperature periods. Parasitism of BSM pupae was higher at Kiboko than Katumani, and Opius phaseoli Fischer (Hymenoptera: Braconidae) was the most common parasitoid.
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Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
surveys/sampling/distribution
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ophiomyia phaseoli	Beans (Phaseolus)	Kenya
	Ophiomyia spencerella	Beans (Phaseolus)	Kenya
Phaedrotoma phaseoli (parasitoid)	Ophiomyia phaseoli	Beans (Phaseolus)
Phaedrotoma phaseoli (parasitoid)	Ophiomyia spencerella	Beans (Phaseolus)