Evaluation of an integrated pest management program for central Washington pear orchards

Abstract

Pear psylla and honeydew marking to fruit cause significant economic damage to pears in Washington, a key pear growing region of the United States. The goal of this project is to compare an integrated pest management (IPM) program using materials which selectively target pests and relies on large natural enemy populations to grower standard conventional and organic pear pest management. In six locations throughout the growing region three management techniques organic, conventional and IPM were designated to 2 ha plots in grower managed orchards. Natural enemy and pest populations were monitored using beat tray, leaf brush and trapping methods. Pest excreted honeydew levels on leaves as well as fruit marking were measured to compare the relative success of pest management programs. IPM programs, using materials which selectively target pests, successfully increased natural enemy populations and kept psylla and honeydew levels low at the end of the season. However, early season pest populations resulted in fruit marking in some years. Fruit quality in IPM programs was similar to organic orchards in 2018, and organic and conventional in 2019, but fruit quality varied by orchard. In order to maintain consistent season-long control, further revision of IPM programs for Pacific Northwest pears is necessary including management tools such as targeted insecticide applications, honeydew washing systems using designated overhead sprinklers, and natural enemy thresholds.