Whats going on with grasshoppers and farmers in the West?
If youve been disappointed by the recent absence of hordes of cicadas across the United States, dont worry: Grasshoppers are here to plug that bug-shaped hole in your heart. Theyre also here to eat huge swaths of cropland, denude trees and other plant life, and generally wreak havoc on the West and its agriculture. If bunched together, it would be like a small sheep that can eat its bodyweight each day.  Scott Schell  Thanks to extreme drought conditions and last years fairly large population of the dry climateloving insect, concerningly dense swarms of grasshoppers are descending on the Western United States. The outbreak is causing concern amongst farmers across the West, from Utah to Wyoming to Montana, who are worried for their crops and livelihoods: Oregon rancher Richard Nicholson described the insect swarms as a scourge of the Earth to the Guardian. At the same time, conservationists warn of adverse impacts from widespread insecticide usage. Advertisement  Advertisement  Advertisement  Slate spoke with Scott Schell, an entomologist who studies rangeland grasshopper ecology and management at the University of Wyoming, about the grasshopper invasion and whats being done to minimize the damage. Our conversation had been edited and condensed for clarity. Scott Schell: If you piled all of the grasshoppers in outbreak areas in the West into one pile  itd be quite numerous. But some of the reports have made it sound like the entire West is awash in grasshoppers, and that isnt really true. We do have areas in some states that are heavily infested. Were really not too concerned with grasshopper numbers until they get up to at least 14 per square yard on rangeland. For perspective, 15 adult two-striped grasshoppers per square yardtheyre a large speciesequals about 100 pounds of grasshopper per acre. If bunched together, it would be like a small sheep that can eat its bodyweight each day of green forage on each acre of range. Advertisement  This year, were talking about, in some places, maybe 5060 grasshoppers per square yard. In certain areas, they can get up even higher than that. In some cases its not even so much that theyre going to eat the leaves off the cropin this year, in hot, dry conditions, a grasshopper swarm can land in a field of small grain, and theyll clip the heads off the grain and get some moisture from the stalk. Theyre not even really eating the grain, but theyve made it unavailable for harvest. Grasshoppers easily outcompete larger animals for grass. They consume way more, in proportion to body size than, say, livestock. When theyre growing, in the nymphal stage, grasshoppers can eat more than their body weight per day in wet vegetation. And, in some species, they waste even more. Theyll walk up to a blade of grass, clip it, eat what they want, and drop the rest. They can eat it right as it grows out of the ground. Theyre tiny; theyve got small mouthparts. As the blade tries to grow, theyll just munch it right off. Theyll stay fat and happy while everything else is dying. Advertisement  When you have drought weather, it exacerbates the grasshopper issue. The unprecedented extent of the serious drought in the West, combined with grasshoppers: Youre in bad shape. Montana has started spraying an aerial pesticides to kill grasshopper nymphs before they can develop into adults. Conservationists have pushed back on insecticide use as a strategy for controlling grasshoppers, claiming that they might do more harm than good to the insect population and the ecosystem as a whole. What we [at the University of Wyoming Entomology Extension] recommend is an integrated pest control strategy, where you treat every other swath [of land], so you have untreated areas in the grasshopper outbreak. Grasshoppers are highly mobile, so you dont need to spray every placetheyll move over and get into a treated swath from an untreated swath. We take advantage of the grasshoppers gluttony: They eat a lot, so we can put the insecticide out in really small amounts. Oh no, the grasshoppers are part of the wildlife out on the range! They provide food for other organisms, like our songbirds. But we need to manage them. The grasshoppers at this point in time, if theyre wisely managed with integrated pest management, its better than just letting them go. I think the answer is yes. Grasshoppers, they can persist. When I was doing research for my thesisa long time agoI looked at historic records. Weve seen places where an outbreak would persist for several years. Eventually, with no intervention, the grasshoppers would succumb to weather events. When they hatch in the spring, theyre about the size of a grain of rice, so theyre pretty vulnerable. Theyre all native, these grasshoppers, so theres also a whole host of other arthropods and insectseven micethat feed on them and help to suppress the grasshopper population. The other thing is it can get so bad in a drought, with less forage, that grasshoppers who cant migrate will starve out. A long time ago, a professor of mine was doing research on the glaciers Wind River Range. Theres some in Montana and some in Wyoming called Grasshopper Glaciers because when people visited those areas theyd often find grasshoppers emerging from the toe of the glaciers. What that was was swarms of the Rocky Mountain locust, riding the winds, which took them to the top of the glacier, where they got too chilled to fly anymore, so they were slowly incorporated into the glacier and eventually spit out the bottom. In those, we essentially have a historic record of grasshopper outbreaks [from hundreds to possibly thousands of years ago], at least the times when swarms flew into the mountains. At lowor I guess you could say normalgrasshopper population densities, I find them fascinating. They play an important role on the rangeland. I think probably all the large mammals could disappear and have less of an impact on the rangeland than if all the grasshoppers disappeared. Grasshoppers play an important role out there. But, when they get to be really thick, like an outbreak where you have 50 or 100 grasshoppers per square yard and theyve eaten everything down to the dirt, theyre obnoxious. I guess Im kind of split. Im really fascinated by them, but as a pest, I can see why people hate them.