With the ultimate goal of controlling infestations of saltcedar in many diverse locations across the western U.S., our plan is to test performance of several biotypes of leaf beetles (Diorhabda elongata), an approved insect for the biological control of saltcedar. What is known is that when the beetle eats as little as 5 percent of a saltcedar, the remaining foliage dries up, causing as much as 100 percent defoliation and ultimately killing the tree.

We need to anticipate which biotypes will be most appropriate for infested regions of the U.S. Suitability is based first on day length, and secondly on host taxonomy, as some species and genotypes of saltcedar (Tamarix) are more susceptible to damage than are others. Implementation of the saltcedar biocontrol program was initiated in late 2005, but only for the northern tier states (north of 38 degrees) based on results, including ours, indicating that mismatched time of birth and development would occur further south. We still conclude that different ecotypes would be more appropriate even in parts of this northern tier of states, and given evidence that most implementation introductions failed, we anticipate that releases in 2007 will be informed by the results of our ecotype testing research.