Abstract: The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), is an international quarantine insect pest. After invasion to China, it rapidly spreads and becomes a major pest, showing an expanding population trend. The absence of effective natural enemies in China has been a key factor for the high population density of the fall webworm. In its native range, the fall webworm is considered a minor pest, and available literature on its occurrence and natural enemies is limited and mostly outdated. Therefore, investigating the occurrence of the pest and its natural enemies in its native range not only enriches our understanding of its biology but also provides valuable insights for managing and controlling the pest in invaded regions. Based on the occurrence investigation conducted in Delaware, USA, the feeding preferences and natural enemies of the fall webworm were further examined in its native range. The results revealed that, among the 39 plant species investigated in Delaware, the fall webworm fed on 33 species, with 25 species being particularly preferred. The species were: Fraxinus pennsylvanica, Quercus rubra, Rubus coreanus, Rhamnus utilis, Pyrus calleryana, Betula nigra, Juglans nigra, Quercus aliena, Cercis canadensis, Lonicera chrysantha, Lonicera macckii, Paulownia tomentosa, Ilex opaca, Chionanthus virginicus, Lindera glauca, Acer platanoides, Cerasus avium, Viburnum acerifolium, Morus alba, Prunus perulata, Tilia cordata, Viburnum plicatum, Erechtites hieraciifolius, Acalypha australis, and Celastrus orbiculatus. The preferred plant species in USA differed from those in China. Compared to the pests in pure forests, the pupae of fall webworm in mixed forests were attacked by more species of natural enemies, for longer durations, and at higher probability. The primary predators of the fall webworm in its native range were ants, ladybugs, and jumping spiders, while its pupae were parasitized by parasitic flies. In the future, continue survey of the parasitoid species in the native range is needed, which may provide technology and products for biological control of the pest in the invaded areas.

Key words: Hyphantria cunea, native range, feeding preferences, natural enemy resources, biological control