Beetles, Weevils, and Scales, Oh My! Monitoring of three biocontrols for salt cedar in the Trans-Pecos Texas and Southeast New Mexico

• In Event: Terrestrial Ecology & Management Oral Session 1

Abstract

Saltcedar (Tamarix spp.) is a deciduous shrub or small tree that was introduced into the United States from Eurasia in the early 1800s to stabilize riverbank erosion, serve as a windbreak, and as an ornamental. However, due to a high reproductive potential, saltcedar has become invasive on many river systems in the western United States. Some of the most dense tamarisk infestations have occurred in the southern areas of the Rio Grande, and in an attempt to control this plant by biological means, the consortium consisting of the USDA, NRCS, and Sul Ross State University released several species of tamarisk leaf beetle (Diorhabda spp.) in southern Brewster and Presidio counties in Texas. The suitability of the species was evaluated, and data suggested that the Tunisian Subtropical species (D. sublineata) was best suited to this region. Observations have also shown that the tamarisk leaf beetles are capable of establishing on a close relative non-target species, the athel tree (T. aphylla). Six sites along the Río Grande River, from Lajitas, TX to Candelaria, TX, have been routinely monitored to determine the long-term impact of leaf beetle defoliation on saltcedar and the non-target athel trees in the region. While defoliation by D. sublineata has been sporadic this past year, activity by other biocontrols, namely the splendid tamarisk weevil (Coniatus splendidulus) and the tamarisk scale (Chionaspis spp.), has been increasing. Efforts were made to broaden the search for all three biocontrols, documenting activity across the Trans Pecos Texas and southeastern New Mexico.

Authors

• Chris M Ritzi, Sul Ross State University

• Alexandra M Hassenflu, Sul Ross State University