Improved Scouting Procedures and Deployment of Physical Control Tactics for Colorado Potato Beetle (Leptinotarsa decemlineata, Say) in Wisconsin Potato Production
A better understanding of early season Colorado potato beetle colonization patterns in fresh market and commercial potato is a critical component for adequate season-long management. Development of descriptive models based upon habitats surrounding previous year potato will provide insight into how this pest utilizes non-crop spaces to overwinter. Models coupling potato rotation in space with landscapes descriptive of high colonization risk will promote innovative IPM strategies focused on discrete application of reduced-risk insecticides (e.g. trap crops), physical barriers such as trenches, or augmentative biological control techniques.
1) validate spatially explicit colonization models to improve established scouting procedures
2) target new control tactics (physical barrier tactics) at locations where greater protection is warranted.
In 2011 we deployed plastic lined trenches for control of Colorado potato beetle at a field scale. Treatments consisted of different colored trenches (either yellow or black) which were either covered or uncovered to exclude overhead irrigation. Preliminary experiments showed beetles were effectively trapped in both black and yellow trenches equally. Exclusion of irrigation resulted in a trend of higher beetle trapping due to less escapes when trenches were wet.
In addition to trenches we utilized historic and contemporary commercial potato scale field counts to generate descriptive models to better understand Colorado potato beetle colonization dynamics at a landscape scale. Statistical models integrated both prior cropping history and local landscapes surrounding those previous potato fields. Each of these components were determined from GIS layers of land use and cropping history for each sample year. Data generated was related to actual pest counts in the field. Information produced indicated that potato rotation in space is an important component to reduce Colorado potato beetle infestation in some, but not all years. Furthermore certain landscapes (e.g. Grasslands) negatively correlated with pest abundance. Though not a strong association, this mechanism may describe an important avenue to be explored in the future for improved mitigation of early season colonization.
For the 2012 season we will continue to refine our Colorado potato beetle colonization model by integrating descriptive statistics into a model validation effort. We will be again sampling potato fields based upon prediction from our previous model to see if it is possible to identify areas of higher or lower risk for colonization. Results will better inform efforts to control Colorado potato beetle at the local landscape scale within certain areas of fields based upon prior cropping history and surrounding non-crop composition.
Impacts and Contributions/Outcomes
We will be submitting the first of two manuscripts addressing Colorado potato beetle colonization in the spring of 2012. The second will be submitted in the fall of 2012. In addition to peer reviewed products we will be submitting a comprehensive article to the Badger Commontater (a monthly magazine targeting Wisconsin potato producers) and presenting results at the UW-Extension and Wisconsin Potato and Vegetable Association 2013 Grower Education Meeting.