Improved Scouting Procedures and Deployment of Physical Control Tactics for Colorado Potato Beetle (Leptinotarsa decemlineata, Say) in Wisconsin Potato Production

View the project final report

• 2011 annual report

Commodities

• Agronomic: potatoes

Practices

• Crop Production: crop rotation
• Education and Training: extension, on-farm/ranch research
• Pest Management: cultural control, field monitoring/scouting, integrated pest management, prevention
• Production Systems: agroecosystems

The Colorado potato beetle (CPB) has been a significant pest of potato in Wisconsin since 1866. For the past 15 years, potato growers in Wisconsin have relied almost exclusively upon a small suite of insecticides called the neonicotinoids to control CPB. The widespread adoption and at-plant use pattern associated with these compounds has led to insecticide resistance in localized populations in the state. This insecticide resistance combined with a behavioral aversion to the insecticide through protracted emergence from overwintering has resulted in multiple, resistant life stages simultaneously present in the field. Because these different CPB lifestages are not all equally susceptible to the residual concentrations of neonicotinoids present after planting, extra foliar applications are often necessary to achieve adequate control. These additional inputs directly impact non-target organisms, increase the risk of environmental contamination, and are expensive for the grower to apply. As a result, there is a need to further develop IPM strategies where localized populations of resistant beetles exist. These new strategies, or insecticide resistance management tactics, will require an improved understanding and more complete characterization of CPB overwintering emergence and colonization patterns into potato fields. Here, we propose to 1) validate spatially explicit colonization models to improve established scouting procedures and, 2) target new control tactics (physical barrier tactics) at locations where greater protection is warranted. The development of inexpensive cultural control tactics in this region will improve the sustainability of our overall management of this insect by reducing the need for additional insecticide sprays thereby reducing impacts on non-target organisms and reducing grower input costs. By combining multiple crop scouting strategies and control tactics with emerging technologies, we can better integrate fundamental, research-based information about CPB population biology into a more ecologically sound, prescriptive management program for Wisconsin potato producers.

Objective 1: Validate spatially explicit colonization models to improve targeted, strategic scouting activities

Six cooperating growers will be identified at the 2011 & 2012 Wisconsin Potato and Vegetable Grower’s Meeting in Stevens Point, Wisconsin. Farmers will be asked to identify potato acreages from both 2010 and 2011 and 16 fields will be randomly selected from the identified potato acreages. Field boundaries will be digitized into a GIS (ArcGIS 9.2) Field edges will then be split into 16 equidistant sample points based on edge length. Sampling location designations will be appended then incrementally buffered at 100 meter radii to 1000 meters.

Buffers will be intersected with an standardized landuse data layer produced from the Portage, Waushara, and Adams County landuse layers. Information will be distilled into a 9 class scheme. Habitat classifications will be consistent with those established by the NRI-Managed Ecosystems Project. A layer intersect process for each buffer zone will quantify acreage of all land classes within its boundary. The resulting data set produced will be comprised of information quantifying landscape features surrounding sample fields. Insect numbers will be described based upon landscape colonization models produced from the 2008 growing season. Counts will be conducted for four weeks in June until the pupation of first generation CPB. Predicted and actual pest counts will be compared based upon landscape composition and a regression analysis of data collected in 2011 & 2012 will be used to validate the models developed in 2008.

Objective 2: Evaluate spatially targeted beetle trenches as a physical barrier for early season CPB colonization.

Deployment of trenches in 2011 & 2012 will occur on commercial acreages demonstrating significant beetle pressure in past seasons. Participating growers will be asked to identify anticipated 2011 & 2012 potato acreages.

A plastic mulch layer was modified in 2009 to create 12 inch deep plastic lined trench in a single pass. The trencher will be used again in 2011 to create beetle trenches. Each sampling location will receive a paired treatment of 200 foot trenches, one of standard black plastic and another of yellow plastic mulch. Each trench will be subdivided into five 20 foot sampling intervals. Trapped beetles will be counted and removed weekly during the month of June 2011 & 2012.