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“I would have bet a lot of pear trees to overwinter on other hosts, though many remain in the orchard. Winterform females pass the winter in a state of reproductive dia- pause and then lay eggs on pear trees in the spring. Summerform adults develop through several generations in the orchard. Guédot looked at differences in the money there’s no way these things had a sex pheromone in diapausing and post - diapausing winterform females. Postdiapausing females—the psylla that return to the orchard in the spring ready to mate—have more of the chemical than diapausing females or males. She is also studying the pheromone of summerform females and has found that although they are in an orchard from May until Septem- ber, they do not appear to be attractive to males through- out the season. Tedious work A patent for the chemical is pending. Horton said the discovery is significant in the research world as it’s possi- ble that pheromones for other psyllid pests could be identified using the same method. Guédot said that identifying the psylla pheromone was far more difficult than it would be for other types of insects, such as moths. “These insects are not easy to work with,” Horton agreed. That’s partly because they are small, but also because behavioral studies have to be done in just the right condi- tions with insects of just the right age. For example, pheromone.” —Dave Horton olfactory tests seem to work best in the afternoons, for some unknown reason. “It took a lot of pretty tedious behavioral work at the start to begin coming to the conclusion that there might be a volatile sex pheromone involved,” he said. Horton has been working on pear psylla since he joined the ARS in Yakima as postdoctoral entomologist in the 1980s and had been convinced that pear psylla didn’t have a sex attractant. Scientists had noticed that male and female psylla tended to congregate, he said, but there were theo- ries that vision or auditory signals were involved or that the males were attracted to shoots that had already been fed on by the females. “We didn’t understand that very well, and nobody really pursued it real heavily until the mid-2000s. I would have bet a lot of money there’s no way these things had a sex pheromone.” While the discovery opens up the possibility of trap- ping psylla more easily, Horton said many growers don’t monitor the pest because it shows up reliably on the trees as soon as the buds start to swell in the spring. Growers who do monitor can use the beating tray method. He said growers seem interested in using the pheromone to disrupt the males as they return to the orchard after the winter to mate, but that’s not being actively explored, as the ARS researchers are focusing on the basic pheromone research. “We don’t know if the compound is volatile enough for that,” Horton said. • Unmatched Performance, Quality Built and Affordable! Best Technology We have been using Victair Sprayer on our own farm for 40+ years. When I went into business for myself, the Victair was a natural choice. It has exceptional coverage (what else do you buy a sprayer for), it’s easy to maintain, and using lower HP tractors saves on fuel costs. While in the commercial application business for 35 years, we have sprayed grapes, almonds, tree fruit, citrus, walnuts, and pecans. This sprayer can handle them all. Because of the small droplet technology (50 micron), we can use less water while maintaining coverage and, therefore, less chemicals—usually 30 to 40 percent less. This is the compact sprayer that can really handle the big jobs. It’s the best technology on the market. Larry Meisner, Kerman, California ENGINEERING RELIABILITY & PERFORMANCE 1801 Presson Place, Yakima, WA 98903 509-248-0318 fax 509-248-0914 hfhauff@gmail.com www.hfhauff.com www.goodfruit.com GOOD FRUIT GROWER JUNE 2011 31 H. F . HA UFF C O M P A N Y I N C .