2009 Annual Report
1a.Objectives (from AD-416)
Biological control strategies will be evaluated for management of emerging cotton pests and the exotic weed, Arundo donax. The lethal and sub-lethal effects of pesticides on key natural enemies of glassy-winged sharpshooter will be investigated to support IPM programs for this pest. Specific objectives are:.
1)Identify, collect, culture, and evaluate candidate natural enemies for efficacy against lepidopteran pests, including the beet armyworm and the cotton bollworm, as well as the green cotton mirid;.
2)Evaluate the effects of pesticides on selected natural enemies of glassywinged sharpshooter and selected predaceous spiders in the cotton agroecosystem;.
3)Evaluate the potential of entomopathogens to manage the varroa mitre and glassywinged sharpshooter; and.
4)Determine the distribution and origin of Arundo donax, giant reed, in the Rio Grande River Basin, and assess the potential impact of candidate biological control agents to manage this invasive weed of riparian habitats.
1b.Approach (from AD-416)
The BIRU will discover and evaluate beneficial insects and pathogens for biological control of the most serious pests and weeds of agriculture in the southwestern U.S., with applications of this research at the national and international level. Changes in cotton production in this region due to the potential eradication of the boll weevil and adoption of transgenic Bt cotton varieties has reduced use of broad spectrum insecticides to control key pests. This pest management strategy has resulted in the emergence of formerly secondary insects such plant bugs as serious pests. New management strategies must be developed to reduce the pesticide use in cotton. The biology and ecology of these emergent pests will be investigated, with the goal of learning where they originate before entering crops, identifying their natural enemies, devising methods to manipulate or otherwise conserve them, and to import new natural enemies for classical biological control. Further, the role of nocturnal spiders will be investigated to quantify the important role they play as predators of Lepidoptera eggs (beet armyworm & bollworm) and to support their conservation in the agroecoystem. The effects of pesticides on key natural enemies, including those of the green cotton mirid and glassy-winged sharpshooter, will be measured, and least toxic insecticides will be identified. This will allow producers to reduce their pest problems while protecting natural enemies. The insect pathology program will concentrate on technology transfer of a pathogen treated hive strip for control of varroa mite with honey bees. Water resources are critical to agriculturists, land managers, and urban users in the arid southwestern U.S. A biological control program to manage giant reed, an exotic water-using weed in the Rio Grande Basin, will be initiated.
USDA-APHIS permitted release of the stem-galling wasp Tetramesa romana and releases were made in Texas in April 2009. In June 2009, Technical Advisory Group for Biological Control of Weeds (TAG) recommended release of the scale insect Rhizaspidiotus donacis. Quarantine host range and biology studies have been initiated for two new agents, the Arundo fly, Cryptonevra sp., and the Arundo leafsheath miner, Lasioptera donacis. The host range studies of the Arundo fly have concentrated on native and economic grasses with large shoots similar to A. donax. Limited egg lay has been documented on non-Arundo species, but no development occurred on these non-target grasses. The biological studies determined the size and duration of the immature life stages; the size, longevity and fecundity of the adult stage for the Arundo fly. Mass rearing and mass aerial application methods have been developed for release of the Arundo wasp in the Pilot Study in Laredo, TX. Inundative releases began in May in Laredo. More than 90% of the A. donax stems in the test plots showed evidence of damage by the Arundo wasp. Two methods for aerial release of T. romana were tested: chilled release machine and paper bags. Both methods are suitable, but the paper bag method has been selected because it is more effective for low-level releases of large numbers of biological control agents. Intensive field testing of biological control agents will continue in 2010 at the pilot study site.
Behavioral and other laboratory assays are evaluating the role of the cursorial spiders feeding on a range of pest species in multiple crops. Of particular importance is the role of non-prey resources in mediating spider populations in crops. Studies continue using behavioral assays to evaluate spider searching and feeding on prey and non-prey resources such as extrafloral and floral nectars. Investigations on predator complexes in cotton have been temporarily suspended due to the on-going boll weevil eradication program. Efforts have been diverted to studying the predator complexes in soybean in support of expansion of regional production of soybean crops. Impact and activity of predators across both day- and night-time periods are being evaluated. These observations will focus on cursorial spiders and the recently discovered Asian cockroach, which has been observed feeding on several pests of annual crops, including cotton.
Significant impact of Arundo wasp and Arundo scale on Arundo donax, giant reed: Specific information about the biology and host range of candidate insects was collected and formed the basis for the field release petitions submitted to the USDA, APHIS, Technical Advisory Group on Biological Control of Weeds (TAG). The Arundo wasp has been permitted and released in Texas. The Arundo scale should be permitted for release in late 2009. Scientists at the Beneficial Insect Research Unit, Weslaco, Texas, will use these two agents to conduct a large-scale, intensive rearing and release program to control A. donax on the Rio Grande River and its tributaries. Biological control is expected to lead to a transition of the riparian zones dominated by A. donax back to native trees and shrubs. This change could lead to significant water conservation in the Rio Grande Basin and provide more cost-effective and sustainable methods to improve visibility and access along the river for law enforcement personnel along the international border.
Shoot fly, a potential biological control agent against Arduno donax, giant reed: Specific information about the biology of candidate insects being considered as biological control agents of giant reed, Arundo donax, is a required part of field release petitions submitted to the USDA, APHIS, Technical Advisory Group on Biological Control of Weeds (TAG). In quarantine laboratory studies, scientists at the Beneficial Insects Research Unit, Weslaco, Texas, determined the size and duration of the immature (larval) life stages of the fly insect Cryptonevra sp., a candidate biological control agent of A. donax. This insect lays eggs in the new shoots of A. donax. The larvae tunnel into the compacted tissue causing death of the new shoot. This accomplishment illustrates the potential for the shoot fly Cryptonevra sp. to establish large, long-lived populations on A. donax, and will form the basis for a release petition to be submitted to the USDA, APHIS, TAG in March 2010.
Release of biological control agents for Arundo donax: The Arundo wasp Tetramesa romana was released in Laredo, TX. This is the first biological control agent permitted for use against the invasive weed Arundo donax. Release of a second biological control agent, the Arundo scale, Rhizaspidiotus donacis, is expected in 2010. Arundo donax is an invasive riparian weed, which is a serious ecological threat to the Rio Grande River Basin and other watersheds in the Southwestern U.S. This program for biological control of an invasive weed has stimulated significant interest and support for the project from the International Boundary and Water Commission, Department of Homeland Security, Bureau of Reclamation, Fish and Wildlife Service, Texas Rio Grande Watermaster, Texas Parks and Wildlife, Texas Department of Transportation, Texas Lower Rio Grande Valley Irrigation Districts, PRONATURA Mexico, and CONANP Mexico.
|Number of Other Technology Transfer||3|
Goolsby, J., Moran, P.J. 2009. Host range of Tetramesa romana Walker (Hymenoptera: Eurytomidae), a potential biological control of giant reed, Arundo donax L. in North America. Biological Control. 49:160-168.
Moran, P.J., Goolsby, J. 2009. Biology of the galling wasp, Tetramesa romana, a biological control agent of giant reed. Biological Control. 49:169-179.
Showler, A., Cavazos, J.O., Moran, P.J. 2007. Dynamics of free amino acid accumulations in cotton leaves measured on different timelines after irrigation. Subtropical Plant Science. 59:38-55.
Hunt, E.J., Kuhlmann, U., Sheppard, A., Qin, T.K., Barratt, I.P., Harrison, L., Mason, P.G., Parker, D., Flanders, R.V., Goolsby, J. 2008. Review of invertebrate biological control agent regulation in Australia, New Zealand, Canada and the USA: Recommendations for a harmonized European system. Journal of Applied Entomology. 132:89-123.
Patt, J.M., Pfannenstiel, R.S. 2009. Characterization of restricted area searching behavior following consumption of prey and non-prey food in a cursorial spider, Hibana futilis. Entomologia Experimentalis et Applicata. 132:13-30.
Pfannenstiel, R.S. 2008. Development of the cursorial spider, Cheiracanthium inclusum (Araneae: Miturgidae), on eggs of Helicoverpa zea (Lepidoptera: Noctuidae). Journal of Entomological Science. 43(4):418-422.
Yang, C., Goolsby, J., Everitt, J.H. 2009. Using QuickBird satellite imagery to estimate giant reed infestations in the Rio Grande Basin of Mexico. Journal of Applied Remote Sensing. 3:033530.