The success of biological control with host-specific natural enemies demonstrates that alternative technologies that are not chemically driven can be very effective in suppressing invasive species.вЂќ вЂњTahitian farmers have said their fruit production has improved in comparison to years when the sharpshooter was in abundance. вЂњPopulations of the glassy-winged sharpshooter have been successfully maintained at a very low level in Tahiti for over two years, the time our experiments ended,вЂќ Hoddle said. By December 2005, the wasp had colonized the entire island of Tahiti, and glassy-winged sharpshooters decreased in number at all study sites to less than 5 percent of their original population density.ДЄs a result of the rapid and dramatic reduction in the population of the glassy-winged sharpshooter in Tahiti, several problems associated with the pest diminished, such as excessive feeding on plants, high levels of sharpshooter excrement raining from trees, and home and shop invasions by hundreds of sharpshooters at night due to the pestsвЂ™ attraction to lights. When the islandвЂ™s government scientists approached Hoddle for guidance in 2003, he agreed to assist.ДЄfter safety evaluations, Hoddle and his colleagues released nearly 14,000 parasitic wasps at 27 sites in Tahiti between May 2005 and October 2005, resulting in rapid parasitism of glassy-winged sharpshooter eggs. The pest was especially present in high numbers in urban areas along the coast where it was severely affecting the health of trees and bushes upon which massive numbers of pests were feeding.

With no type of natural control in Tahiti, the excessive number of glassy-winged sharpshooters was a major social, economic, and agricultural nuisance on the island. Study results appear in the February issue of Biological Invasions. The parasites spread naturally and on their own, and they fly, requiring little, if any, continuous human assistance over a wide geographic area.вЂќ вЂњWhen biological control вЂ“ the use of a pestвЂ™s natural enemies to keep the pestвЂ™s population growth in check вЂ“ works, it is very effective and safe in most cases. вЂњWe had the technology to do the job cheaply and in a way that brought about permanent control of the glassy-winged sharpshooter in Tahiti and its neighboring islands,вЂќ said Hoddle, an extension specialist in the Department of Entomology and the director of the Center for Invasive Species Research. The wasp larva completes its development inside the host egg and then emerges as a tiny winged parasite that searches for more glassy-winged sharpshooter eggs to kill. The wasp larva that hatches from the egg then eats the inside of the glassy-winged sharpshooter egg, killing it. The tiny stingless wasp attacks glassy-winged sharpshooter eggs by drilling a tiny hole in the egg through which the parasite lays its own egg. The method involves introducing Gonatocerus ashmeadi, a microscopic parasitic wasp, into an ecosystem under siege from the glassy-winged sharpshooter.

Wasp sharpshooter