MORPHOLOGY, DISTRIBUTION, AND THE ROLE OF TRICHOMES IN COWPEA (VIGNA-UNGUICULATA) RESISTANCE TO THE LEGUME POD BORER, MARUCA-TESTULALIS (LEPIDOPTERA, PYRALIDAE)

Studies on the morphology and distribution, and the role of trichomes in damage to cowpea (Vigna unguiculata) by the legume pod borer Maruca testulalis (Geyer) showed that trichome cover on individual cultivars varied in trichome length and density, but not in trichome type from different plant parts. Trichome density on different parts decreased with increasing plant age. Significant (P <0.05) negative correlations were obtained between total trichome density on pods, pod infestation and damage severity. In contrast, correlations between length of non-glandular trichomes on pods, pod infestation and damage severity were not significant. Results suggest that trichome length may be less important than density in reducing pod damage by M. testulalis in cultivated cowpeas. It is, therefore, concluded that breeding for a higher level of trichomes in high yielding and agronomically desirable cowpea cultivars, will serve as an important component in the integrated management of M. testulalis.