摘要：It has been conjectured that global warming will increase the prevalence of insect pests in
many agro-ecosystems. In this paper, we quantitatively assess four of the key pests of
maize, one of the most important systems in North American grain production. Using
empirically generated estimates of pest overwintering thresholds and degree-day
requirements, along with climate change projections from a high-resolution climate model,
we project potential future ranges for each of these pests in the United States. Our analysis
suggests the possibility of increased winter survival and greater degree-day accumulations
for each of the pests surveyed. We find that relaxed cold limitation could expand the
range of all four pest taxa, including a substantial range expansion in the case
of corn earworm (H. zea), a migratory, cold-intolerant pest. Because the corn
earworm is a cosmopolitan pest that has shown resistance to insecticides, our
results suggest that this expansion could also threaten other crops, including those
in high-value areas of the western United States. Because managing significant
additional pressure from this suite of established pests would require additional pest
management inputs, the projected decreases in cold limitation and increases in heat
accumulation have the potential to significantly alter the pest management landscape
for North American maize production. Further, these range expansions could
have substantial economic impacts through increased seed and insecticide costs,
decreased yields, and the downstream effects of changes in crop yield variability.
