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United States Department of Agriculture

Agricultural Research Service

Research Project: Pilot Program to Evaluate the Effectiveness of Biological Control to Reduce the Impact of Invasive Carrizo Cane on the Rio Grande River

Location: Livestock Arthropod Pest Research

Project Number: 3094-32000-036-42-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 10, 2013
End Date: Sep 9, 2018

ARS will conduct research on biological control of Arundo donax L., carrizo cane, giant reed, which is an exotic and invasive weed of riparian habitats and irrigation canals of the Rio Grande River Basin and the southwestern U.S. Carrizo cane dominates these habitats, which leads to: loss of biodiversity, catastrophic stream bank erosion, and reduced visibility for law enforcement activities on the U.S.-Mexico border. Additionally, this invasive weed facilitates the incursion of cattle fever ticks from Mexico and competes for water resources in an arid region where water resources are critical to the environment, agriculture, and municipal users. Biological control using insects from the native range of carrizo cane may be the best option for long-term management of this weed. Carrizo cane is a good target for biological control because it has no close relatives in North or South America, and because several of the plant-feeding insects from its native range in Mediterranean Europe are known to be specialists, feeding only on this one plant species and significantly decrease the size, density, and invasiveness of carrizo cane. The research program includes: field evaluation, foreign insect collection, quarantine evaluation of candidate insects, mass rearing of permitted agents and aerial distribution of agents on the Rio Grande. This multi-faceted program is required to gain for approval of biological control agents. The goal of the program is to demonstrate the effectiveness of biological control as a management tool for reducing carrizo cane density, which in turn is likely to increase visibility of the border to a degree that meets the needs of DHS/CBP.

USDA-ARS, Edinburg, TX, will take the lead on this research in collaboration with the ARS European Biological Control Laboratory in Montpellier, France. The research evaluates the field impact of both arundo wasps and arundo scale insects (from Europe) on A. donax on the Rio Grande. Most of the field work will take place in the USDA-APHIS permanent quarantine zone for the cattle fever tick, where A. donax is invasive and provides an optimum habitat for survival of this serious livestock pest. One of the key measures of success for the biological control program will be an increase in visibility caused by reduction in above-ground A. donax biomass. Visibility measures through the infested and un-infested stands of A. donax under daylight conditions will be used to evaluate any changes in vegetation density that increase visibility or line of sight of the Rio Grande. Research to improve mass rearing of the arundo scale will be conducted to increase the number and quality of scale for release at the field sites in Del Rio, Laredo, Los Indios, and other sites as designated by DHS. Farmland operated by USDA-ARS in Weslaco, TX, will be used to mass rear the arundo scale. Newly emerged arundo scale crawlers will be released at field sites by USDA aircraft to maintain their vigor and increase impact. Lastly, work will continue to evaluate the effectiveness and safety of the third candidate biological control agent, the arundo leaf miner. This research includes, biological studies, host range testing, pre-release impact studies and other information needed by the TAG (Technical Advisory Group for Biological Control of Weeds) and USDA-APHIS in order to gain approval for the release of the leaf miner for release in North America. ARS will collaborate with Texas Agrilife, the University of Texas - Pan American, and Instituto Mexicano de Tecnologia de Aguas to extend the benefits of the program throughout the Rio Grande Basin.

Last Modified: 10/20/2017
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