Efficacy of Xylocoris flavipes (Reuter) (Het., Anthocoridae) to suppress Prostephanus truncatus (Horn) (Col., Bostrichidae) in traditional maize stores in southern Togo

In the course of three storage periods (1988-90) the predacious insects tha t occur in traditional maize stores in southern Togo were observed and thei r relationship to the introduced pest Prostephanus truncatus was investigat ed. The bug Xylocoris flavipes, a predator on a wide range of post-harvest pests, was the only one observed regularly and in higher numbers. Laborator y trials with P. truncatus showed that the larvae were preyed on, and no pr eference for any one of the three instars was detected. On average, 7.3 pes t larvae were killed by larvae or adults of the predator. In glass jar tria ls on loose maize X. flavipes reduced the numbers of P. truncatus by 57.6% after 8 weeks. The losses and damage were reduced by 50 and 17.6%, respecti vely. Observations in traditional maize stores indicated a tendency to decr easing populations of X. flavipes when populations of P. truncatus increase d, presumably due to the unfavourable environmental conditions created by t he pest. Therefore, it is concluded that X. flavipes does not play an impor tant role in the control of this pest.