Identification of sources of resistance in cowpea, Vigna unguiculata L. Walp. to Clavigralla tomentosicollis Stal. (Hemiptera: Coreidae)
1991
Olatunde, G.O. | Odebiyi, J.A. | Chiang, H.S. | Jackai, L.E.N.
Thirty-six cowpea cultivars were evaluated for their resistance to the pod-sucking bug, Clavigralla tomentosicollis Stil. in the screenhouse and in field experiments. Absolute resistance was not found in any of them, although cultivars with relatively low percentage seed damage were present. Seventeen cultivars were significantly less damaged than the susceptible check in the field experiments. Seven cultivars had less than 60% seed damage. Of these, TVu 3354, TVu 3355, TVu 3372, TVu 8525 and TVu 3199 were the least damaged. Per cent seed damage on cultivars in the field was not consistent with that in the screenhouse, because of the influence of other pod-sucking bug species and environmental factors. Yield components such as 100 seed weight and the number of pods per plant were related to the resistance of the test cultivars to the bug attack. Cultivars with smaller seeds and more pods per plant were less damaged. The number of seeds per pod was not related to the degree of seed damage. Similarly, morphological parameters of the cultivars were not related to the degree of seed damage.
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