It’s a hazy Sunday morning in early July as Levi Jamison pulls to the side of the road in central New Mexico. He grabs a camera, clipboard and thick canvas insect net from the blue Volkswagen van that is his traveling home and office, and begins to hike along an irrigation ditch just east of the Rio Grande. A seemingly unending thicket of tall, shrubby tamarisk trees parallels the ditch. He stops just a few feet in, picks a tree at random, and sweeps the net over the dusty-green leaves exactly five times. Then, he peers into the canvas, quickly counting a mass of tiny Diorhabda beetles already crawling up the fabric to escape.
He scribbles the number — “160,” he says — and the GPS coordinates in his notes. That’s a drop from the 200 or 300 per net he’s seen here before. Jamison, a biologist now with the Colorado Plateau Research Station at Northern Arizona University, has long tracked the tamarisk leaf beetle through the Southwest. One trip, he says, these trees dripped with beetles.
Whether that’s a good thing depends on whom you ask. These Old World beetles were imported and released in the early 2000s as a biological control for tamarisk, a once-beloved Eurasian tree that now monopolizes vast stretches of western waterways.