Impact Magazine - Spring 2008 - (Page 11)

Pam Roberts, left, and Phil Stansly examine citrus at the Southwest Florida Research and Education Center in Immokalee for greening symptoms and the presence of the Asian citrus psyllid that spreads the disease. photo by thomas wright Roberts, an associate professor of plant pathology, in collaboration with Diana Schultz, an assistant in plant pathology with advanced training in molecular biology. Biological Control In an attempt to reduce populations of the psyllid, Marjorie Hoy, a professor of entomology and eminent scholar, and Ru Nguyen, an entomologist with the Division of Plant Industry (DPI) at the Florida Department of Agriculture and Consumer Services in Gainesville, imported and released two natural enemies of the citrus pest from Taiwan and Thailand in 1998. One of the beneficial wasps, Tamarixia radiata, is now widely established throughout Florida, and the second wasp, Diaphorencyrtus aligharensis, may be present in very low numbers. Hoy and her colleagues found that Tamarixia radiata — a host-specific natural enemy that attacks immature Asian citrus psyllids — declines during the winter because the psyllid does not reproduce on citrus during cooler weather in Florida. “As a result, populations of Tamarixia lag behind the psyllid when it begins to reproduce in early spring,” Hoy said. “Tamarixia increases to higher densities late in the season — August to November — reaching parasitism rates as high as 98 percent.” She said it’s unlikely that any host-specific wasp can successfully overwinter in high numbers unless the psyllid Using a PCR (polymerase chain reaction) technique, Marjorie Hoy evaluated the proportion of Asian citus psyllids in Florida citrus groves carrying the greening bacterium and found a very low incidence of infected psyllids during the fall and winter of 2005-2006. Jason Meyer, not pictured, a graduate student in the entomology and nematology department, assisted with the research. “Our research suggests that it may be more important to remove infected trees than to attempt to kill every psyllid in an effort to reduce transmission of greening disease,” Hoy said. photo by tyler jones IMPACT | Spring 2008 11

Table of Contents Feed for the Digital Edition of Impact Magazine - Spring 2008

Impact Magazine - Spring 2008 Contents A Big Boost for Biofuels Top Priority Partnerships for Sustainable Agriculture Eliminating the Evil Weevil Invasive Pest Defeating Resistant Roaches Biodiesel Boon User-Friendly Updates for FAWN Flat-Out Great for the Grill! Laser Labeling Cashing in on Caviar Saving Water with Soil-Moisture Sensors Spotlight IFAS Development News

Impact Magazine - Spring 2008

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