Greenhouse Production Constraints in Cowpea (Vigna Unguiculata): A Case Study of Aphis Craccivora Infestation, Fungal Disease, and Experimental Performance

Abstract

This case study examines a major biotic disruption observed during the greenhouse component of a previously published cowpea (Vigna unguiculata) experiment evaluating Rhizobium spp. inoculation and inorganic fertilization. The primary agronomic outcomes of the parent investigation have already been published and are not presented here as a new efficacy trial. Instead, the present report focuses on the severe Aphis craccivora infestation, concurrent fungal disease, unequal plant loss, and the implications of these events for experimental performance and interpretation. Four original treatment groups were included: untreated control, inorganic fertilizer, inorganic fertilizer + Rhizobium spp., and Rhizobium spp. alone. Before harvest interpretation was compromised, greenhouse plant height differed among treatments (F = 8.881, p < 0.001), whereas basal diameter did not (F = 1.735, p = 0.174). Active nodules were recorded descriptively in the inoculated groups. Following the biotic disruption, only 3, 10, 14, and 21 plants remained at final harvest in the control, inorganic fertilizer, inorganic fertilizer + Rhizobium spp., and Rhizobium spp.-only groups, respectively. Because aphid abundance, infestation duration, and fungal etiology were not experimentally controlled or quantified, these unequal survivor counts cannot be interpreted as evidence of treatment-mediated resistance to aphid infestation or fungal disease. This case illustrates how an unplanned pest–disease episode can confound greenhouse biofertilization experiments and emphasizes the need for systematic pest surveillance, predefined intervention criteria, disease diagnosis, and transparent reporting of compromised endpoints.