The oriental fruit moth (OFM), Grapholita molesta Busck, has recently emerged as a pest of major economic importance in commercial apple production. While OFM has long been a significant pest problem on stone fruits, the reasons for OFM outbreaks on apple are unknown. One possibility is that an OFM host shift to apple is ecologically favored, due to host-driven effects on OFM development and/or reproduction. This study seeks to understand the effects of the host plant on OFM development. The egg phenology of OFM populations in the field was examined on both apples and peaches. Two years of data indicate that OFM egg hatch occurs earlier on peaches than on apple, especially on later generations of OFM that occur late in the growing season. The effects of host plant on larval development were also examined. Larvae from a local, field-collected, laboratory-reared OFM population were released onto enclosed apple and peach trees in the field. Larval developmental time was examined on the growing shoots of non-bearing apple and peach trees as well as on the growing fruit of apple and peach trees. Many current models of OFM phenology are derived from developmental data on a single host plant. To achieve more accurate outputs, phenological models may need to be modified, in order to account for the effects of other sympatric host plants on OFM development over the course of the growing season.
Species 1: Lepidoptera Tortricidae Grapholita molesta (oriental fruit moth)
Keywords: oriental fruit moth, development
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