Crop pests spread due to warming


Crop-damaging insects, bacteria, fungi and viruses are moving pole-ward by nearly 3 km each year, helped by global warming, a study said Sunday.

A team at Britain’s University of Exeter trawled through two huge databases to chart the latitude and dates for the earliest record of 612 crop pests.

Since 1960, these pests have been heading toward the poles at a rate of around 2.7 km yearly. They move into land that opens up for habitat because of higher temperature and its impact on weather.

“If crop pests continue to march pole-wards as the Earth warms, the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security,” said one of the authors, Dan Bebber.

The study, appearing in the journal Nature Climate Change, said half of the pests are spread by humans, hitchhiking for instance on traded produce, and half are spread by the weather.

Recent examples include the mountain pine beetle, a highly damaging pest for forests, which has moved into newly warmed habitats in the U.S. Pacific Northwest. There is also fusarium head blight, also called scab, which has emerged as a threat to wheat in the United States. Another peril is rice blast fungus, which is present in over 80 countries and has now moved to wheat.