Saltcedar (Tamarix spp.), an invasive tree or shrub has infested riparian areas throughout the western United States. Field testing of potential biocontrol agents of saltcedar, such as Diorhabda elongata has been hindered by population explosions of the specialist leafhopper, Opsius stactogalus, inside field cages. The study was designed to evaluate biotic and abiotic factors that may cause O. stactogalus populations to increase dramatically inside field cages. Cages were set up at Leyendecker Research Center near Las Cruces, NM. Leafhoppers and predator numbers were counted on trees inside and outside of field cages. Stems were chosen at ground level, 90cm, and 180cm above the ground on each of the four cardinal directions on each tree (a total of 12 stems/tree). Each stem was marked at 30cm and 90cm. Leafhoppers were counted along the terminal 30cm, and predators were counted along the terminal 90cm of each stem. Temperature and humidity were compared inside and outside of cages. Finally, leafhopper dispersal was evaluated. This study found that temperature and humidity were significantly different inside vs. outside of cages; however, the biological significance of these differences is being analyzed. Predator counts inside the cages were higher than in control plots, suggesting that lack of predators was not the cause for population increases. Analysis of dispersal data is still being analyzed.
Species 1: Homoptera Cicadellidae Opsius stactogalus
Keywords: Tamarix, predators
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