The bean fly (Ophiomya sp.), also known as bean stem maggot, is one of the most important field pests of common bean in Eastern and Southern Africa (ESA). Three species have been reported as important pests: Ophiomyia spencerella, O. phaseoli, and O. centrosematis. Their prevalence is dependent on altitude, with O. phaseoli and O. spencerella being dominant in the lower and high altitudes respectively. Yield loss due to bean fly in common bean is poorly documented, although it is reported to range between 10-100%. The extent of yield loss depends on the species, timing and level of infestation, susceptibility of the bean cultivars, as well as environmental factors such as humidity, temperature and rainfall.

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Recommended control methods include the application of chemical pesticides, however prolonged use of chemical pesticides poses health and environmental hazards and is an additional expense to farmers. Early planting, use of fertilizers and intercropping are some of the cultural practices to control the bean fly. However, the success of cultural control methods can be low under heavy insect pest pressure. Incorporating host resistance to common bean cultivars would be an effective, reliable and environment friendly method to control bean stem maggot.