Oedophrys hilleri (Faust), native to East Asia, has become established in the north-eastern United States. This study examined the feeding preferences of adults, larval food and phenology of adults in an unsprayed peach orchard. Adults fed on the foliage of plants in the Rosaceae family preferring peach (Prunus persicae) and pear (Pyrus communis). There was one generation per year, adults were most abundant in late June to early July but were present whenever trees were actively growing. Eggs were laid on the soil surface. Larvae fed on the fine roots and the cambium and xylem tissues of small woody roots of peach trees; roots of other species were not tested. In field observations, adult feeding removed up to 15% of the foliage on individual branches. An estimated high of 337 adults/m² emerged from the soil under peach trees based on enclosed emergence traps. Although heavily infested trees showed no apparent loss of vigor compared with trees in the same orchard with low levels of defoliation, this exotic insect could be of concern to growers when combined with other orchard stresses.