Good Fruit Grower

February 15

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Biocontrol photo by Callie baker Enhanced Katie Mulvaney monitoring an apple block in spring, using a beat tray. M onitoring is one of the key components of any successful integrated pest management program, because it provides a window into what is going on in an orchard. This is true not only for pests but also for natural enemies. New monitoring tools, developed as part of the multistate project ���Enhancing Biological Control in Western Orchards,��� have shown that the presence of some natural enemies in orchards is much higher than previously thought. The project focused on using plant volatile lures to monitor key natural enemies and determine the time during the growing season when they are present. Ultimately, the information gleaned from these tools will aid growers in making informed management decisions that include the conservation of natural enemies. Historically, biological control has been diffiby Andrea Bixby-Brosi, Vince Jones, cult to measure. Traditional monitoring methods, Dave Horton, Tom Unruh, Nick Mills, like beating trays or yellow sticky cards, have a Peter Shearer, and Jay Brunner tendency to underrepresent certain natural enemy groups or life stages. They also collect only individuals that are active within the immediate sampling time and space. Their use can also be time-consuming or require a high level of taxonomic knowledge when a multitude of insects is caught. These limitations lead to false impressions of low natural enemy abundance, and assumptions that biological control is of little value in the area sampled. Biological control is typically noticed only when it���s not working. For example, pesticides can Knowing what���s in your orchard helps to stabilize your IPM program. 32 FEBRUARY 15, 2013 GOOD FRUIT GROWER disrupt the balance between natural enemies and pests, resulting in secondary pest flare-ups (i.e., aphids and mites) and the need for additional sprays. HIPVs The discovery of herbivore-induced plant volatile lures has greatly improved natural enemy monitoring. HIPVs are natural chemicals released by plants (volatiles) when they are wounded by the feeding of insects (herbivores). Natural enemies use these volatiles to detect the location of food (prey or hosts). HIPV lures in combination with traps can capture natural enemies continuously, day and night, and can draw insects in from a large area, making them an advantageous monitoring tool. Sticky traps of various colors used in combination with HIPV lures allow us to monitor a diversity of predators and parasitoids. HIPVs can attract a single species or a broad range of natural enemy species. For example, lures containing the HIPV squalene are highly attractive to the green lacewing, Chrysopa nigricornis. An odor blend containing geraniol, methyl salicylate, and 2phenylethanol (known as GMP) is highly attractive to a broad range of natural enemies, including syrphid (or hover) flies, the predatory bug Deraeocoris brevis, parasitic wasps, and the green lacewing Chrysoperla plorabunda. So far, we have tested 54 possible blends of compounds in apples alone. To some extent, attractive blends can be tailored to target certain natural enemies that are important in different cropping systems. Using HIPV lures, we���ve been able to compare natural enemy densities before and after insecticide sprays, and throughout the growing season in conventional and organically managed photo by Callie baker Natural enemy INVENTORY

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