Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2017
Publication Date: 2/20/2018
Citation: Neven, L.G., Kumar, S., Yee, W.L., Wakie, T. 2018. Current and Future Potential Risk of Establishment of Grapholita molesta (Lepidoptera: Tortricidae) in Washington State. Environmental Entomology. 47(2):448-456. https://doi.org/10.1093/ee/nvx203.
Interpretive Summary: The oriental fruit moth is a primary pest of stone fruits in the United States. The expansion of the moth’s range could threaten the tree fruit industry in Washington State. Personnel at the USDA Temperate Tree Fruit & Vegetable Research Unit and Colorado State University in Fort Collins, CO used ecological niche models to determine the potential range of the moth in the state and its range under climate change scenarios. The models predicted a small portion of central Washington that is suitable to support the moth, but climate change models predict a large expansion of these suitable areas. These results indicate that action should be taken to monitor and reduce current populations of the moth to stem its potential expansion into the major commercial tree fruit production areas in the state.
Technical Abstract: The oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), is a primary pest of stone fruits in many countries, including the United States. The distribution of this pest is concentrated in areas receiving higher than lower rainfall. It prefers sites where stone fruits and apples are cultivated in close proximity. Both codling moth, Cydia pomonella (L.), and G. molesta are common pests and appear to occupy similar niches, but the biology of G. molesta differs from codling moth in diapause induction and completion requirements as well as host preference and degree day phenology. The objectives of this study were to: (1) identify environmental factors associated with G. molesta distribution, (2) predict the potential distribution of G. molesta in Washington State (WA) using Maxent and CLIMEX models, (3) identify those areas within WA best suited for establishment of Pest Free Zones, Areas of Low Pest Prevalence, and Pest Free Production Areas, and (4) identify regions most at risk for further expansion of G. molesta populations as a function of climate change. The current models predicted a small portion of central WA that is suitable to support G. molesta, which is consistent with observed distributions. However, climate change models predict a large expansion of these suitable areas. These results indicate that action should be taken to monitor and reduce current populations of G. molesta to stem its potential expansion into the major commercial tree fruit production areas in the state.