Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2009
Publication Date: 1/29/2010
Publication URL: http://hdl.handle.net/10113/40004
Citation: Debano, S.J., Hamm, P.B., Jensen, A., Rondon, S.I., Landolt, P.J. 2010. Spatial and Temporal Dynamics of Potato Tuberworm in the Columbia Basin of the Pacific Northwest. Environmental Entomology. 39(1):1-14; DOI: 10.1603/EN08270 Interpretive Summary: New methods and approaches are needed to manage potato tuber moth that has recently become a serious pest of potato in the Columbia Basin of Washington and Oregon. Pheromone lures are used in traps to determining the presence and abundance of this insect pest and can be used to indicate the need to use control measures such as pesticides. Researchers at the USDA-ARS laboratory in Wapato, Washington, in collaboration with the Washington State Potato Commission and Oregon State University have been using pheromone traps to study the geographic and seasonal occurrence of this pest over a multi-year period. They determined that the insect successfully overwinters in the lower elevations of the basin and spreads generally northward through each season. It was also found that the severity of the infestation varies strongly geographically and has lessened, possibly a result of harsher winter conditions in those years. This information has been useful to potato growers in providing real time guidance as to the status of the pest in their area and need for control, and also provides indications of the longer term nature of the pest status of the potato tuber moth in the Columbia Basin.
Technical Abstract: A landscape-scale study from 2004-2006 investigated the spatial and temporal dynamics of a new pest to the Columbia Basin of the Pacific Northwest, the potato tuberworm, Phthorimaea operculella (Zeller). Male P. operculella were monitored in spring, summer, and fall each year with a pheromone trapping network in Oregon and Washington. The objectives of the study were to: 1) describe the temporal and spatial dynamics of the recent outbreak of P. operculella in the region, and 2) examine the relationship of the spatial and temporal distribution of the outbreak with weather (air temperature, precipitation, and dew point) and geographic variables (elevation and latitude). Weather data during the P. operculella outbreak were compared to a reference period (1993-1999) that occurred before the outbreak. The outbreak in 2004, which caused the first widespread tuber damage in the region, was associated with warmer temperatures in the preceding fall, and in the spring, summer, and fall of the growing season. October and November 2003 and March 2004 were also drier than the reference period. However, winter 2003/2004 was colder than the reference period and thus, mild winter conditions did not explain the outbreak. The importance of environmental variables on the seasonal spatial distribution of the pest each year was examined using nonparametric multiplicative regression. Locations with higher spring, summer, or fall temperatures were associated with increased trapping rates in most seasons. Elevation and latitude appeared to play a constraining role; low trapping rates of P. operculella were associated with higher elevations and latitudes.