December 2015 Tamarisk Coalition Newsletter

Our Partners At the Tamarisk Coalition

This article was written in the December 2015 Tamarisk Coalition Newsletter. We are happy to see the success of these lil’ beetles!

Tamarisk Beetle Map

New Tamarisk Beetle Map Released

Tamarisk beetle distribution continues to ebb and flow across the North American continent. In 2015 there was continued expansion along the Middle Rio Grande as southern populations moved north into the Elephant Buttes Reservoir area near Truth or Consequences, New Mexico. Anecdotal data suggest that this movement may have been aided by the interstate corridor and beetles potentially “hitch-hiking” on vehicles.  There was also increased beetle activity and tamarisk defoliation observed this year along the Little Colorado River near Holbrook, Arizona, as well as a similar pattern seen along the Rio San Jose west of Albuquerque.

In most other parts of the country where we have seen heavy defoliation in the past, the beetle populations in 2015 were sparse to non-existent. Populations in west Texas, the Pecos River drainage in New Mexico, the Colorado River in Utah and Colorado, and the Arkansas River in Colorado had relatively low numbers of beetles present, while populations across the plains in north Texas, Oklahoma, and Kansas seem to have virtually disappeared. This pattern was also found in northern Chihuahua state in Mexico where previous southward expansion halted and very few beetles were found. Populations in northern Utah, Idaho, and Oregon have remained fairly constant but have not really expanded, as have populations in northern Montana (for which TC just received data this year but was established in the mid-2000s).

Monitoring is proving to be more and more important as the beetle has not been present in the system for very long and the dynamics of population movement and stability are not yet understood. To become involved in helping to track tamarisk beetle spread and aiding in data collection for the largest ongoing ecological experiment in North America, please visit our website or contact Ben Bloodworth directly at

The production of the Annual Tamarisk Beetle Distribution Map is generously funded by a grant from the Walton Family Foundation.