Prospects for Integrated Pest Management of Brown Marmorated Stink Bug in Washington Tree Fruits

Brown marmorated stink bug (BMSB, Halyomorpha halys) is one of several new invasive pests that threaten tree fruit production in the western US. Based on the experience in the eastern US, there is grave concern that this pest will disrupt decades of progress in IPM, and force producers to return to a regimen of broad-spectrum, non-selective insecticide use. The western US has had over 20 years of warning as BMSB has gradually spread across the US from the original find in Pennsylvania. However, microsatellite analysis indicates that western populations are the result of multiple independent introductions from Asia and the eastern US. Since its initial detection, research efforts in the eastern US have been launched to meet the challenge of this new pest by establishing the fundamentals of BMSB biology, ecology and management. Previous Asian literature was also made available to English-speaking researchers by Lee et al. (2013), who translated and reviewed many formerly inaccessible studies. Despite this progress, re-establishing IPM in eastern orchards has proven difficult. Similar challenges are predicted for the west. Washington is home to a vibrant tree fruit industry, crops which are recognized as being among those at the highest risk to BMSB damage. As BMSB inexorably spreads throughout our state, we are motivated to take any steps possible to prepare for managing this pest. Preserving and perpetuating the current level of IPM begun in the 1990s with the implementation of codling moth mating disruption is one of the highest priorities. Invasive species represent a clear and present danger to IPM programs, especially when they entail the use of broad-spectrum pesticides. While these will still be in our toolbox in case of need, we focus our research on non-pesticidal strategies: biological control, which should help prevent the outbreak conditions experienced in the mid-Atlantic region in 2010, and physical exclusion, which may minimize damage for conventional and organic growers alike. For now, we plan to continue releases of T. japonicus in urban areas and orchard borders, where they are less likely to be impacted by routine sprays, in order to suppress outbreaks proactively. As we modify our orchards to cope with sunburn, net structures will become more common, and can be adapted for BMSB control. BMSB's presence in the Central Valley of California indicates it can tolerate conditions that are even hotter and drier than those in central Washington. If BMSB proves as adaptable to the sagebrush steppe as it has to other environments, then the risk of damage may still be considerable.