Comparative survival rates of oriental fruit moth (Lepidoptera: Tortricidae) larvae on shoots and fruit of apple and peach.

Studies were designed to examine the effects of host plants on oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), survival. G. molesta larval survival in the orchard was comparable between apple (Malus spp.) and peach (Prunus spp.) shoots, indicating that both host species can harbor large larval populations during the early season. G. molesta larvae used multiple shoots for feeding and development on peaches but usually only damaged single shoots in apple. Survival differences were present between peach and apple fruit, but this survival was affected by fruit maturity level. Generally, larval survival higher was in ripening peach fruit than in green, immature apple fruit. Larval survival varied among several apple cultivars, indicating that cultivar-level variability needs to be considered. These host-associated effects may impact efforts to predictively model G. molesta populations in commercial orchards where multiple host plant species, or different cultivars of the same species are often grown in proximity. Thus, host-associated dynamics should be included into future population models that underlie management programs.