Inferences on pod wall and seed defences against the brown cowpea coreid bug, Clavigralla tomentosicollis Stal. (Hem., Coreidae) in wild and cultivated Vigna species

Studies were conducted in the laboratory to investigate the different compo nents of the resistance of Vigna vexillata A. Richards. TVnu 72. and severa l cultivars of cultivated Vigna spp. to infestation and damage by the brown cowpea coreid, Clavigralla tomentosicollis Stal. The main objective was to determine the different roles of the pod wall and seeds, and the relations hip between seed size, number, and damage by this insect. Results show ed t hat both the pod wall and seed clearly contribute different components to t he resistance of TVnu 73 to C. tomentosicollis. Analysis of the results sug gests that the seed defences and the pod wall pericarp mag. be more importa nt than are trichomes in this resistance. Seed number was found to influenc e the extent of damage in a more predictable manner than seed size. However . because both of these traits: are generally inversely related and mutuall y exclusive. their individual effects cannot be completely separated. The i mplications of these traits in a breeding programme targeted at a specific consumer group are discussed.