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Assessing habitat requirements for host plants (Opuntia spp.) of Cactoblastis cactorum in the Southeastern United States. Majure, Lucas *,1, Ervin, Gary1, Madsen, John1, Westbrooks, Randy3, Simpson, Annie4, Sellers, Elizabeth 4, 1 Mississippi State University, MS, USA3 National Wetland Research Center, Whiteville, NC, USA4 U.S. Geological Survey, Reston, VA, USA ABSTRACT- Cactoblastis catorum Berg. (cactus moth), one of the world's most effective biological control agents, is now threatening cacti in their native habitats throughout parts of the southeastern United States. Since being found in the Florida keys in 1989, the moth has rapidly migrated up the east coast to South Carolina and is also moving west through the gulf states where it has been found as far west as Dauphin Island, in southwest Alabama. In order to better predict what westward route this invasive insect might use to continue its spread, it is essential to understand the basic ecology and distribution of Opuntia (prickly pear cactus), the host plants for Cactoblastis. Habitat descriptions icluding vegetation types, soil structure and pH are necessary components for delimiting areas in which these cacti might be found. These and other parameteres were evaluated in sixteen sites located in Mississippi and Alabama where natural populations of Opuntia pusilla (Haw.) Nutt. and Opuntia humifusa (Raf.) Raf. were established. Data suggested that Opuntia were located predominantly on acidic, well-drained soils, with clear associate species that varied to some degree with the regional physiography. This information should help guide future efforts at locating potential host sites for Cactoblastis by indicating areas with highest potential for sustaining populations of these cacti. SPANISH ABSTRACT- Cactobastis cactorum Berg. (palomilla de cacto), uno de los agentes biológicos mas efectivos en el mundo ahora está amenazando hábitats naturales en partes del sureste de los Estados Unidos. Desde gue fue encontrada en los cayos de Florida en 1989, la palomilla se ha emigrado rápidamente subiendo la costa este hasta Carolina del Sur y también está mudandose al oeste por los estados del gulfo donde ha sido encontrado hasta la Isla de Dauphin, en el suroeste de Alabama. Para predecir mejor que ruta éste insecto invasora va a tomar para continuar su expansión , es esencial entender la ecología básica y distribución de Opuntia (cacto de pera espinosa), las plantas huéspedes para Cactoblastis. Descripciones de los hábitats incluyendo los tipos de vegetación, estructura de los suelos y pH son componentes necesarios para delimitar áreas cuales estos tipos de cactos posiblemente puedan ser encontrados. |
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