Possible Impacts of Projected Temperature Change on Commercial Fruit Production in the Great Lakes Region

Commercial fruit production is a primary revenue source for many locations within the Great Lakes region. Projected climate change may have a profound impact on this highly climate sensitive activity, which owes its existence to the moderating influence of the Great Lakes. Downscaled daily maximum and minimum temperature series provided by the U.S. National Assessment were utilized to evaluate 1) possible changes in the frequency and timing of several agronomically-relevant temperature threshold events and 2) potential interactions between crop phenology and a commercially-important insect pest ( Cydia pomonella (L.)). The analyses are for the two future decades of 2025 to 2034 and 2090 to 2099. The assessments for 2025 to 2034 suggest that fruit-growing areas in the Great Lakes region will experience a moderate increase in growing season length and seasonal heat accumulation and a decrease in the frequency of freezing temperatures. In addition, important growth stages will occur earlier in the calendar year than at present. Very large changes in the temperature threshold parameters are projected for 2090 to 2099. However, it is unclear for both assessment decades whether fruit production will be more or less susceptible to damage from cold temperatures after critical growth stages are reached. Projected warming may also result in increases in the number of generations per season of a primary insect pest and the number of necessary pesticide applications.