Fitness of Frankliniella occidentalis and Bemisia tabaci on three plant species pre-inoculated by Orius sauteri

Exploring the interactions between host plants, herbivores, and natural enemies is an important experimental approach for enhancing biological control. Induced plant defense responses following infestation by herbivores enable plants to minimize damage. Orius sauteri (Poppius), an important generalist predator, has been widely used as a biological control agent for suppressing many agricultural pests on agronomic and horticultural crops. Because this predator oviposits and feeds on plant tissue, in this work we hypothesized that these behaviors can induce defenses that modulate the subsequent pest attack. For this, we explored the fitness parameters of two key pests, the western flower thrips Frankliniella occidentalis (Pergande) and the tobacco whitefly Bemisia tabaci (Gennadius), on three different O. sauteri-pre-inoculated plant species, tomato, cucumber, and cowpea when compared to non-pre-inoculated plants. Pre-inoculation of O. sauteri on these three plant species decreased the performance of both herbivore pests but to differing degrees. The survival of F. occidentalis on tomato and B. tabaci on cowpea was significantly reduced on O. sauteri-pre-inoculated plants compared to non-inoculated plants. The reproduction of B. tabaci on tomato, cucumber, and cowpea was decreased in varying degrees by the pre-release of O. sauteri, whereas in the case of F. occidentalis the reproduction was only reduced on tomato and cucumber pre-inoculated plants. These results further enhance our knowledge of ecological relationships between natural enemies and herbivores and provide the context for the early release of natural enemies to control pests.