Progress 09/01/08 to 10/01/11
Outputs
Progress Report Objectives (from AD-416) Evaluate the use of biological control to manage the invasive weed, Arundo donax, carrizo cane. Approach (from AD-416) Insect biological control agents will be mass reared at USDA-APHIS production facilities located in Edinburg, TX. Agents will be released at the pilot study in Laredo, TX. On site measurements will be taken to determine the effectiveness of the agents, release rates, and interactions with mechanical and chemical control methods for Arundo donax. Specialized USDA aircraft will be tested for aerial release of the agents. This is the final report for this project that terminates on October 1, 2011. More than 1 million arundo wasps were reared and aerial releases were made along the Rio Grande between Brownsville and Del Rio, TX. European genotypes of the wasp from the origin of the invasive Rio Grande Basin genotype in Spain are now established along the Rio Grande and in selected locations in central Mexico and northern California. These large-area releases are the result of increased efficiencies in mass- rearing of the wasp and technology improvements for release using ARS aircraft. The wasp is expected to spread from release points and form a continuous population along the Rio Grande and up the tributary rivers where carrizo cane is most problematic. Field studies in Laredo, TX, to determine the impact of inundative aerial releases of the wasp showed moderate increases in damage to the cane, but these study sites were destroyed by historic flooding of the Rio Grande during July of 2010. The arundo scale was permitted on Dec. 17, 2010, for release in Texas. An intensive field collection campaign was conducted in Europe for shipment to U.S. quarantine facilities. Several million scale crawlers (mobile juvenile stage of the scale) were processed and have now been released in Del Rio, TX, and into rearing facilities in the U.S. and Mexico. The scale has established in all release locations, and an intensive field evaluation is underway to document the impact of the scale. Remote sensing, using aircraft-mounted thermal and infrared cameras, is being used to detect changes in plant composition and water use following the release of the biological control agents. The field research is being conducted with the Department of Homeland Security (DHS) . Cost comparisons of carrizo cane control by mechanical and/or chemical methods ($2.3 million per river mile) versus biological control ($20,000 per river mile) illustrate the economics of carrizo cane control options. Our goal is to integrate the biological control program with selective use of mechanical controls (mowing) by DHS to create a stable transition of the river environment from carrizo cane to native trees and grasses. Methods to release the arundo scale by aircraft are under development to allow for deployment of both biological control agents along the 350-mile stretch of the Rio Grande between Del Rio and Brownsville, TX.
Impacts
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) Evaluate the use of biological control to manage the invasive weed, Arundo donax, carrizo cane. Approach (from AD-416) Insect biological control agents will be mass reared at USDA-APHIS production facilities located in Edinburg, TX. Agents will be released at the pilot study in Laredo, TX. On site measurements will be taken to determine the effectiveness of the agents, release rates, and interactions with mechanical and chemical control methods for Arundo donax. Specialized USDA aircraft will be tested for aerial release of the agents. Mass rearing of the arundo wasp has been accomplished with more than 300, 000 wasps produced for field release. Methods for efficient aerial release of the wasp have been developed with APHIS. A large-scale release and evaluation of the arundo wasp was initiated in a pilot study along the Rio Grande near Laredo, Texas. Inundative aerial releases of the wasp into stands of mature A. donax have shown minor impacts but will continue for a full year. The combination of mechanical cutting of the reed to 1 meter plus the releases of the arundo wasp has been shown to reduce regrowth of the reed and allows for transition of the riverbank to native vegetation. Release of the arundo scale has been proposed by USDA- APHIS, and releases of the scale are planned for late 2010. Pre-release studies of the scale have shown that it reduces the vigor of the rhizome (root) of the reed and that the scales from the origin of the Rio Grande Basin genotype in Spain are most effective.
Impacts
(N/A)
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) Evaluate the use of biological control to manage the invasive weed, Arundo donax, carrizo cane. Approach (from AD-416) Insect biological control agents will be mass reared at USDA-APHIS production facilities located in Edinburg, TX. Agents will be released at the pilot study in Laredo, TX. On site measurements will be taken to determine the effectiveness of the agents, release rates, and interactions with mechanical and chemical control methods for Arundo donax. Specialized USDA aircraft will be tested for aerial release of the agents. Significant Activities that Support Special Target Populations Arundo donax L., carrizo cane, giant reed, is an exotic and invasive weed of riparian habitats and irrigation canals of the Rio Grande River Basin (RGB) and the southwestern U.S. Carrizo cane dominates these habitats, which leads to: loss of biodiversity; catastrophic stream bank erosion; damage to bridges; increased costs for chemical and mechanical control along transportation corridors; and impedes law enforcement activities on the international border. Additionally, this invasive weed competes for water resources in an arid region where these 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. Arundo donax is a good target for biological control because it has no close relatives in North or South America, and several of the plants feeding insects from its native range in Mediterranean Europe are known to be specialists feeding only on this one plant species. Carrizo cane is a major impediment to Department of Homeland Security, Customs and Border Protection (DHS-CBP) operations on the international border between Laredo and Del Rio. An interagency agreement is in place with DHS to accelerate the existing ARS A. donax biological control program. The research has many components including mass rearing/application of agents. One agent, the Arundo wasp, Tetramesa romana, was permitted for release by USDA-APHIS in 2009. In April 2009, a mass rearing and inundative release program using the Arundo wasp was tested at the DHS Carrizo Cane Pilot Study Site in Laredo, Texas. These studies tested the combination of the biological control of the Arundo wasp with mechanical and chemical control of A. donax. The mature stands of A. donax along the Rio Grande were cut by private contractors using power equipment and the stumps were painted with the herbicide, Imazapyr. Following the herbicide application, new shoots of A. donax emerged within two weeks. Releases of the Arundo wasp were made by ARS personnel for several weeks at an average rate of one wasp per shoot. This release rate caused significant stunting of the treated regrowth. This first field inundation test was considered a success because it eliminated the need for two additional applications of herbicide that were applied to the adjacent Arundo in the mechanical/chemical test area of the pilot study. Further research is planned to evaluate the impact of Arundo wasp releases on mature stands of A. donax on the Rio Grande.
Impacts
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