UW Extension entomologist says warmer climate could boost grasshopper numbers
March 7, 2016
University of Wyoming Extension entomologist Alex Latchininsky said a wetter, warmer climate may contribute to future locust outbreaks like that harassing Argentinians and could also boost future grasshopper infestations in Wyoming and the West.
Officials say Argentina is facing its worst plague in more than half a century, with the New York Times last month reporting farmers in 2015 sighted locust clouds more than 4 miles long and nearly 2 miles high.
The locust species causing havoc in Argentina is the South American locust, Schistocerca cancellata, noted Latchininsky. Because of the crops it feeds upon, economic importance is high.
Latchininsky, a professor in the Department of Ecosystem Science and Management, was asked by the Weather Channel how climate change may affect future locust outbreaks and how insufficient control efforts may contribute. Latchininsky, in the College of Agriculture and Natural Resources, is an international consultant for the Food and Agriculture Organization of the United Nations and advises agencies in the United States on grasshopper control and monitoring.
Climate change may influence the South American locust in two ways, he said.
More abundant rains in its breeding areas could trigger an outbreak due to likely producing three generations instead of one, and higher temperatures may allow the locust to expand its range to the south, said Latchininsky.
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Some locust species (for example, the Moroccan locust Dociostaurus maroccanus) in Central Asia expanded its distribution ranges to the north because of warmer temperatures.
Grasshoppers in Wyoming could also get a climate-change boost, developing faster and producing more offspring, Latchininsky said.
Some Western Hemisphere subtropical grasshoppers have expanded their ranges northward like the Moroccan locust. The gray bird grasshopper Schistocerca nitens, whose northern-most boundary has been south Texas, was spotted several times in Wyoming near Cheyenne and Lusk.
"This shows the great migratory potential of these grasshoppers," Latchininsky said. "Like locusts in the Old World, they can expand their ranges to the north when temperature rises."
Locust swarms from South or Central America invading Wyoming is unlikely, he said, but last year showed an upsurge of the native grasshopper numbers in the state.
In a couple of years, that may lead to a widespread grasshopper outbreak similar to that in 2010 when over 6 million acres of rangelands were protected from these pests, Latchininsky said.
As for South America, efficient monitoring systems should be established in the South American locust's traditional breeding areas in the north of Argentina for control, said Latchininsky. Some of those areas are hard to access and are insufficiently monitored. He advised breeding areas should have anti-locust treatments, against early-instar hoppers.