The exotic tamarisk tree is a familiar sight if you’ve ever poked around in any ditch, stream or river on the Colorado Plateau. The presence of this aggressive riparian competitor has become a hot topic in a variety of arenas, including ways to manage the invasive tree. In 2001, Diorhabda spp., better known as the tamarisk leaf beetle, whose larvae feed primarily on the leaves of the tamarisk tree, was approved for release as a bio-control agent. They have since spread steadily along the Colorado River watershed, finally landing in Grand Canyon National Park. Since  their arrival more than two years ago, the beetles have spread to roughly 50 percent of the near 275-mile stretch of the Colorado. Monitoring the beetle’s progress and where they lay their eggs will shed light on the various locations where established tamarisk tree populations may die off as they become defoliated by the beetle. Here’s a glimpse of a late-April research effort, heading down river in search of this tiny, leaf-hungry insect.
 

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  Head researcher and boatman, Levi Jamison, examines riverside foliage near Tanner Canyon.

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  Counting a tamarisk tree’s inhabitants after a sweep.

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  Wildlife biologist Dave Erickson sweeps tamarisk trees for beetles, larvae and their predators, near mile 200.

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  Floating through a serene section of Marble Canyon.

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  Tamarisk beetle researcher Clark Tate takes science to the next level in Hermit Rapid.