Bemisia tabaci (Gennadius) is an economically damaging invasive pest to global vegetable production. Current management strategies rely heavily on insecticides, but increasing levels of resistance raise sustainability concerns. Therefore, strengthening integrated pest management (IPM) programs requires enhancing biocontrol through improved predator-pest interactions. Despite the well-established relevance of functional response modulation by multiple environmental factors, limited research has explored how plant traits and prey life stages interact to influence the efficiency of generalist predators in vegetable systems. To address this gap, we evaluated the functional responses of 2 adult generalist predators, Hippodamia convergens (Guérin-Méneville) and Geocoris punctipes (Say), against 3 nymphal instars of B. tabaci (second, third, and fourth) on 2 vegetable crops: yellow summer squash (Cucurbita pepo L.) and green beans (Phaseolus vulgaris L.) at 6 prey densities (5, 15, 25, 50, 75, and 100) under laboratory conditions. Results showed that both predators successfully preyed on all nymphal instars. Overall, predation did not differ significantly between host plants but varied among nymphal instars and increased with prey density. Both predators exhibited a Type III (sigmoidal) response to second instars and a Type II (hyperbolic) response to third and fourth instars. Attack rate increased with prey stage, with H. convergens showing the highest attack rate on fourth instars. Our findings highlight the importance of prey life stage in determining predator efficiency and support the potential of H. convergens and G. punctipes as promising biocontrol agents of B. tabaci, contributing to the development of more effective IPM strategies for vegetable production systems.
Aigbedion-Atalor et al. (2026) studied this question.