ISHS Acta Horticulturae 668: I International Humulus Symposium
CONSERVATION BIOLOGICAL CONTROL AND HIPPOs IN ARTHROPOD PEST MANAGEMENT IN WASHINGTON HOPS |
| Authors: | D.G. James, S. Castle |
| Keywords: | conservation biological control, mites, aphids, herbivore-induced plant protection odors |
| Abstract:
Conservation biological control combined with the use of selective pesticides is a practical pest management strategy for mites and aphids in Washington hops. This strategy generally reduces miticide/aphicide inputs by 50-75%. In some instances complete biological control can be achieved. The key to effective biological control is spring recruitment of a complex of winged predators of mites and aphids, for example, pirate bugs, big-eyed bugs, mite-eating ladybeetles and lacewings. Early colonization of hops by these beneficial insects inhibits development of mite and aphid ‘hotspots’, minimizing the risk of widespread infestations occurring. Predatory mite populations generally reach high levels by mid summer and contribute to biological control until harvest. Insufficient recruitment of winged predators during spring may lead to a need for single applications of bifenazate for mites and pymetrozine for aphids. These materials kill mites and aphids without interfering with predator population development. Current research is aimed at improving the reliability of predator recruitment in spring through the use of a synthetic herbivore-induced plant volatile, methyl salicylate. Methyl salicylate has been demonstrated to be an attractant for a number of mite and aphid predators in Washington hops, and appeared to enhance biological control in hop yard studies in 2003. The use of synthetic plant-signaling compounds as “Herbivore-Induced Plant protection Odors” (HIPPOs) may provide a novel, yet practical management option for improving the efficacy and reliability of conservation biological control in hops. | |
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