Predation by generalist predators on the codling moth versus a closely‐related emerging pest the oriental fruit moth: a molecular analysis

Abstract

Biological control by conservation of native natural enemies can, at its best, reduce the need for pesticides and prevent detrimental effects upon the environment. The present study investigated the role of ground‐active generalist predators as natural enemies of two tortricid pests in apple orchards. Predation rates were compared on the well established codling moth Cydia pomonella and the emerging oriental fruit moth Grapholita molesta, which has recently switched hosts to apples. The present study hypothesized that the ground‐active predators consumed the two tortricid pests in significant numbers without preference, and attacked the pests at different developmental stages. Using diagnostic polymerase chain reaction on the gut contents of field‐caught ground‐active predators, no difference in predation rates was found on these two pests. Spiders were the most efficient predators of emergent adult moths in spring, whereas the carabid beetles, feeding on diapausing larvae, were important in the autumn. The temporal complementarity between spiders and carabid beetles, attacking different stages of the pests at different times of year, highlights the need for diverse predator assemblages to optimize biological control.