By Courtney Swyden
Results from a Texas A&M Entomology graduate student’s research on using saltcedar beetles as a biological control for saltcedar showed that in one year the insects can help defoliate this invasive, water consuming tree.
“Results from field cage and natural experiments indicate that one full season of defoliation has adverse consequence for the trees,” said Jeremy Hudgeons. Hudgeons and advising professors, Drs. Allen Knutson, and Kevin Heinz, focused on determining the effectiveness of using this leaf-eating beetle to help control the saltcedar invasion.
“Tree starch reserves were reduced and tree regrowth was less after beetle defoliation,” he said. “We believe three to four years of tree defoliation by the insects can result in tree death.”
Saltcedar, also known as tamarisk, was imported into the United States in the 1800s as an ornamental plant and the trees were planted along some stream banks as a form of erosion control.
“Before beginning graduate school, I had firsthand experience of the devastating impact saltcedar has in its non-native habitat,” he said. “Streams can become so choked with the trees that they are virtually inaccessible if not nonexistent.”
The negative attributes of saltcedar were beginning to be noticed by the 1920s. In heavily infested areas, saltcedar reduces stream flow, increases fire frequency, decreases native plant and animal diversity, and consumes significant amounts of water.
“Working with landowners and local, state and federal cooperators, I was able to monitor open field releases of the beetles and conduct a large-scale field experiment studying the effects of beetle feeding on saltcedar trees,” said Hudgeons, a recipient of a $5,000 2005-06 U.S. Geological Survey research grant.
Hudgeons surveyed two sites in West Texas in which saltcedar leaf beetles were released to determine if the beetles were establishing and dispersing. Beetles have successfully established at one of the sites and have defoliated more than 400 trees in a four acre area. He also measured the impact beetle defoliation has on tree starch reserves and determined the potential for tree re-growth following beetle feeding.
Hudgeons received his bachelor’s degree in molecular biology from Texas Tech University. He said he wants to pursue a career in natural resource management in either the private or public sector.
His research was funded by TWRI through the USGS as part of the National Institutes for Water Research annual research program. TWRI is the designated institute for water resources research for Texas.
For more information on Hudgeons’ research, visit “USGS Research Grants”.
