Sweet cherries, Prunus avium (L.) L.,
grown in the western United States are exported to many countries
around the world.
Some of these countries have enforced strict quarantine rules and trade
restrictions owing to concerns about the potential establishment and
subsequent spread of western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), a major quarantine pest of sweet cherry.
We used 1) niche models (CLIMEX and MaxEnt) to map the climatic
suitability, 2) North Carolina State University-Animal and Plant Health
Inspection Service Plant Pest Forecasting System to examine chilling
requirement, and 3) host distribution and availability to assess the potential for establishment of R. indifferens in areas of western North America where it currently does not exist and eight current or potential fresh sweet cherry markets: Colombia, India, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and Vietnam.
Results from niche models conformed well to the current distribution of R. indifferens
in western North America.
MaxEnt and CLIMEX models had high performance and predicted climatic
suitability in some of the countries (e.g., Andean range in Colombia and
Venezuela, northern and northeastern India, central Taiwan, and parts
However, our results showed no potential for establishment of R. indifferens
in Colombia, Indonesia, Malaysia, Taiwan, Thailand, Venezuela, and
Vietnam when the optimal chilling requirement to break diapause (minimum
temperature < or = 3 degree C for at least 15 wk) was used as the
criterion for whether establishment can occur.
Furthermore, these countries have no host plant species available for R. indifferens.
Our results can be used to make scientifically informed international trade decisions and negotiations by policy makers.