SUSTAINABLE SOLUTIONS TO PROBLEMS AFFECTING BEE HEALTH

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1004784
• Multistate No.: NC-_old1173
• Project Start Date: Nov 28, 2014
• Project End Date: Sep 30, 2015
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF WISCONSIN
21 N PARK ST STE 6401
MADISON,WI 53715-1218

Performing Department
Entomology

Non Technical Summary
Production and processing of specialty crops in Wisconsin is an important contributor to the local and regional economy. Equally important, specialty crops rely on pollinators for fruit and seed production. Wisconsin specialty crop producers continue to rely heavily on neonicotinoid insecticides for the control of many insects. Reported at-plant applications of soil-applied neonicotinoid insecticides have occurred on nearly 90% of all acres. Another critically important and recent observation surrounding the use of neonicotinoids is the recently reported detections in Wisconsin's groundwater. In 2008, the WI-DATCP began testing for the neonicotinoid insecticides in groundwater wells in Wisconsin. Since testing began, concentrations of thiamethoxam were observed in 35 separate well samples, but none are above enforcement levels. Recent well sampling (2011) has further confirmed that overhead, irrigation systems are applying contaminated groundwater to flowering crops and at times when pollinators are presumably present. The impact of these chronic, low-dose exposures to the bees is completely unknown. In this project, we propose to investigate (1) the spatial and temporal structure of groundwater contaminants, (2) the sites and sources of low-dose pesticide contaminants in sentinel flowering plants, (3) the response of local bee communities to an increase in pesticide contamination resulting from groundwater contaminants.

Animal Health Component

40%

Research Effort Categories

Basic

60%

Applied

40%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
111	0210	2050	20%
133	3099	1150	40%
216	1310	1130	40%

Knowledge Area
133 - Pollution Prevention and Mitigation; 111 - Conservation and Efficient Use of Water; 216 - Integrated Pest Management Systems;

Subject Of Investigation
1310 - Potato; 3099 - Bees, honey, and other pollinators, general; 0210 - Water resources;

Field Of Science
1130 - Entomology and acarology; 2050 - Hydrology; 1150 - Toxicology;

Keywords

pollinators

groundwater

pesticides

neonicotinoids

Goals / Objectives
To determine how land management practices affect pollinator nutrition and how nutrition affects honey bee colony productivity and success To determine the effects of interactions among various factors affecting pollinator and honey bee colony health To develop and recommend "best practices" for beekeepers, growers, land managers and homeowners to promote honey bee and pollinator health

Project Methods
Continuation of work done in WIS01706. A first set of experiments will be completed to satisfy Objective 5. A spatially structured experimental design will be used in the Central Sands region to quantify variation in neonicotinoid detection across two spatial scales: 1) sites less than 3.5 km in distance apart, and 2) sites greater than 15 km apart. At each of 3 sample dates throughout the 2013 and 2014 growing season (May, July and September), 1L water samples will be taken from fully operational high capacity wells in each experimental site, with a total of 5 wells sampled per site totaling 45 wells at each sample date. Water samples will be returned to the laboratory and the concentrate. We will use a two-level, hierarchical design to determine variation in pesticide detection at spatial scales ranging from 3.5 to 15 km. Aditionally, supplementary experiments will be conducted to characterize the potential sites and sources of low-dose pesticide contaminants in sentinel flowering plants placed under overhead irrigation systems. We will use sentinel cucumber and alfalfa plants placed into fields with operating irrigation wells. Sentinel plants will be grown to the flowering developmental stages and transferred to select field sites where they will be placed in fields to receive varying numbers of overhead irrigation events, plus a control. Specifically, replicate sets of plants will be exposed to 0, 1, 2, and 4 successive irrigation events prior to tissue sampling to determine the concentration of neonicotinoids (e.g. thiamethoxam). Leaf, pollen, and nectary tissues will be sampled from plant replicates at each site for insecticide residue detection. A second set of experiments will be implemented to satisfy Objective 3. Specifically, we will measure the response of sentinel bee colonies to an increase in pesticide contamination resulting from groundwater contaminants applied to flowering plants. A randomized block design experiment will be conducted at selected sites over two growing seasons, 2013-2014. The experiment will consist of a total of 5 replicate blocks at each location. The treatment factor among locations will be the cumulative concentrations of thiamethoxam exposure accumulated in replicate sets of flowering plants. A bumblebee hive will be sheltered in a wooden structure to protect the hive against weather conditions. Multiple structures (3-6) for leaf cutter bees will be placed in each plot. Pollinator health will be measured for these bumblebees and leafcutter bees. We plan to disseminate research results and describe measurable outcomes in support of Objective 7. The outcomes of the generated research will (1) begin to build a more comprehensive picture of the extent of neonicotinoid contamination in the upper Midwest production region, (2) the potential for neonicotinoid movement into groundwater resources, and (3) the extent of off-site movement of selected neonicotinoids through a cluster analysis water-monitoring survey.

Progress 11/28/14 to 09/30/15

Outputs
Target Audience:Research objectives outlined in this study were anticipated to benefit agricultural producers, crop consultants, University of Wisconsin Specialists and County Educators, and other stakeholders and were considered essential for properly determining the potential impact of irrigation contaminants on the potneitl for impacts upon pollinator health. Improvement of environmental quality through fundamental and applied research in Wisconsin will provide the necessary incentive for growers to reinvest in reduced risk practices. Promotion of innovative groundwater management practices within the USDA and NRCS's Environmental Quality Incentive Program (EQIP) may further promote greater awareness and acceptance of these practices through economic incentives. Proposed outcomes of our research were consistent with objectives of the U.S. Farm Bill which addressed pest management needs of the growers while working to limit non-target impacts to the environment. Moreover, the outcomes of the generated information which has (1) built a more comprehensive picture of the extent of neonicotinoid contamination in the upper Midwest production region, (2) described the potential for neonicotinoid movement into groundwater resources, and (3) begun to describe the extent of off-site movement of selected neonicotinoids through a cluster analysis water-monitoring survey. Changes/Problems:No significant changes were made to this project. What opportunities for training and professional development has the project provided?The graduate research assistant (GRA) assigned to this project was able to attend and deliver research results at reional and national meetings including the Wisconsin Potato and Vegetable Growers Association, the Entomological Society of America's National Meetings and the American Phytopathological Society of America. The GRA assigned to this project also attended and participated in supplemental training on Geostatistics and Spatial Analysis offered through the University of Wisconsin's Biometry Program. The GRA also worked very closely with staff scientists from the Wisconsin Department of Agriculture, Trade and Consumer Protection's, Water Quality and Analytical Laboratory to learn techniques including Liquid Chromatographic Mass Specrotemetry for the detection of low-dose concentrations of insecticides in water and plant tissue samples. How have the results been disseminated to communities of interest?Results have been disseminated through a combination of resources including (1) peer-reviewed, scientific journal publication, (2) field days and producer meetings, (2) regional and national meetings of Professional Societies (e.g. ESA and APS). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Experimental results were presented through the horticultural crops Extension Entomology program via field days (2014 and 2015, Hancock Potato Field Days), the vegetable extension newsletter (http://www.plantpath.wisc.edu/vegetable-newsletter-supplement-3-released), and formal conference presentations including the WPVGA Grower Education Conference in both 2013 and 2014. Research results were also published in the scientific literature through a combination of research venues as follows: • Huseth, A.S., Groves, R.L., Chapman, S.A., Alyokhin, A., Kuhar, T.P., McRae, I.V., Szendrei, Z. and Nault, B.A. 2014. Managing Colorado Potato Beetle Insecticide Resistance: New Tools and Strategies for the Next Decade of Pest Control in Potato. J. Integ. Pest Mgmt. 5(4):http://dx.doi.org/10.1603/IPM14009. • Huseth A.S. and Groves, R.L. 2014. Environmental Fate of Soil Applied Neonicotinoid Insecticides in an Irrigated Potato Agroecosystem. PLoS ONE 9(5): e97081. http://doi:10.1371/journal.pone.0097081. • Huseth, A.S., Lindholm, J., Groves, C.L., and Groves, R.L. 2014. Variable concentration of soil-applied insecticides in potato over time: implications for management of Leptinotarsa decemlineata. Pest Mgmt. Sci. 70:1863-1871. In this study, we observed high concentrations of neonicotinoid insecticides in potato foliage within two weeks of crop emergence followed by a sharp decline as the season progressed. Similar patterns in soil-applied insecticide concentrations have been documented for several different application methods (e.g. seed, in-furrow, drip, and drench) in other annual herbaceous crops as well as perennial tree, shrub, and vine crops. This rapid reduction in concentration is intriguing as these declines closely correspond with expansion of the potato canopy in early June. Other studies in annual crops seldom indicate the potential of rapid plant growth as a factor affecting the dilution of concentrations of the insecticide. Reduction in the concentrations of these insecticides at the time of canopy expansion increases crop vulnerability to direct damage by insect herbivores and also increases the potential for pathogen transmission. Furthermore, the non-uniform distribution of systemic insecticides in (among and likely within) plants creates the potential for refugia to be present within both within and among plants resulting in increased selection pressure for accelerated insecticide resistance development later in the season. Major rainfall events did not significantly influence detections of neonicotinoids in the experimental area. Early season rainfall was not exceptionally heavy in either year of this experiment. The accumulation of leachate detections in lysimeters likely is reflected by the steady application of irrigation water and rainfall. One clear exception to this pattern occurred in 2012 at 155-156 days after planting when 89 mm of rain fell within a 24-hour period. Peak detections of thiamethoxam in 2012 began to trend upward following this rain event, however the timing of similar detections across treatments in 2011 occurred at about the same time. One additional explanation may be that increased levels of pesticide losses are associated with plant death or senescence. In each year of this study, the largest proportion of pesticide detections in leachate occurred shortly after vine killing in potato. Vine killing in commercial potato production is a common practice designed to aid the tubers in developing a periderm. Perhaps the rapid loss in root function following plant death permits excess pesticide to be solubilized and washed through the soil profile more quickly in root channels. In both seasons of this study, however, large episodic rain events did not occur early in the growing season. These results do appear, however, to document low to moderate levels of leaching losses that occur throughout the season even when the crop is managed at nominal evapo-transpirative need. Untreated control plots also yielded low-level detections of thiamethoxam throughout both seasons. To better understand these insecticide detections in control plots, we sampled water directly from the center pivot irrigation system providing irrigation directly to the potato crop. Samples were taken while the systems were operational from lateral spigots mounted on the well casings. In both years, samples revealed low concentrations of thiamethoxam present in the groundwater at two time points in each sample season from which irrigation water was being drawn. Clothianidin was also present at a single time point in 2012. These positive detections of low-dose thiamethoxam were obviously being unintentionally applied directly to the crop through irrigation and this information is new to the producers in the Central Sands of Wisconsin. Although systemic neonicotinoids have recently been detected from surface water runoff and catch basins associated with irrigated orchards, to our knowledge no other study has documented the occurrence of neonicotinoids in sub-surface groundwater being recycled through operating irrigation wells. Two alternative delivery methods, the side dress and impregnated polyacrylamide treatments, were included in these investigations to determine if the duration of high insecticide concentrations could be extended further into the growing season. Side dress applications were once common with older systemic compounds such as disulfoton (Di-Syston® 15G, Bayer Cropscience, Research Triangle Park, NC) and aldicarb (Temik® 15G, Bayer Cropscience, Research Triangle Park, NC), but have since been discontinued with registration of in-furrow neonicotinoids and voluntary cancellations. In our study, full rate, side dress applications of neonicotinoids showed little benefit in extending the interval of insect control or increase in the residual concentrations of insecticides in the plant. We observed an overall reduction in the residual concentration of both active ingredients associated with the side dress use pattern. However, this study documents that side dress application methods did not result in increased insecticide concentration during the growing season and no statistical increase in control of CPB when compared with other common soil-application methods. Here we found that regardless of the soil application method or neonicotinoid used, insecticides lost efficacy through time, but were still detectible in plant tissues at the conclusion of the study. Under commercial circumstances, growers would make additional foliar applications based on the insect population density and associated defoliation thresholds. For the insect population, multiple modes of action would be operating as a simultaneous selection factor for insecticide resistance within discrete CPB generations. Consideration of the manner in which insecticides are delivered, residual time of each compound, and exposure of to the target pest are all critical components in sound resistance management plans. Sub-lethal, chronic exposures from early season soil-applied insecticides, independent of mode of action class, should be carefully evaluated as a possible contributor to emergence of insecticide resistance selection. Results of this study improve our understanding about the effects of different insecticide delivery methods on in-plant plant concentration profiles through time and the effects of measured pesticide concentrations on CPB.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Huseth A.S. and Groves, R.L. 2014. Environmental Fate of Soil Applied Neonicotinoid Insecticides in an Irrigated Potato Agroecosystem. PLoS ONE 9(5): e97081. http://doi:10.1371/journal.pone.0097081.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Huseth, A.S., Groves, R.L., Chapman, S.A., Alyokhin, A., Kuhar, T.P., McRae, I.V., Szendrei, Z. and Nault, B.A. 2014. Managing Colorado Potato Beetle Insecticide Resistance: New Tools and Strategies for the Next Decade of Pest Control in Potato. J. Integ. Pest Mgmt. 5(4):http://dx.doi.org/10.1603/IPM14009.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: German, T.L. and Groves, R.L. 2014. New directions in pest management. In Proceedings of the 2014 University of Wisconsin - Wisconsin Potato and Vegetable Growers, Grower Education Conference , UW- Madison College of Agriculture and Life Sciences, Research Division and UWEX, Feb. 4-6, Stevens Point, WI, 27:3pps.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Huseth, A.S. and Groves, R.L. 2014. Environmental fate of soil applied neonicotinoid insecticides in an intensively irrigated agroecosystem. In Proceedings of the 2014 University of Wisconsin - Wisconsin Potato and Vegetable Growers, Grower Education Conference , UW- Madison College of Agriculture and Life Sciences, Research Division and UWEX, Feb. 4-6, Stevens Point, WI, 27:2pps.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: ESA Graduate Student TMP Competition, Spatial variation in thiamethoxam detections in groundwater resources in Wisconsin's Central Sands vegetable production region, B. Bradford and R.L. Groves. University of Wisconsin, ESA Annual Meeting, Portland, OR, November 17, 2014.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Entomological Society of America, Annual Meeting. 2015. Graduate Student Poster Competition, Relationships between biotic indices and neonicotinoid insecticide detections in Wisconsins groundwater-fed streams. Bradford, B.Z. and Groves, R.L. ESA Annual Meeting, Minneapolis, MN, November 15-18, 2015.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Entomological Society of America, Annual Meeting. 2015. Ten-minute papers, P-IE Section, IPM General. Neonicotinoid insecticide detections in Wisconsins groundwater resources. Bradford, B.Z. and Groves, R.L. ESA Annual Meeting, Minneapolis, MN, November 15-18, 2015.
• Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Groves, R.L. 2015. Wednesday Night at the Lab, Insect Pest Management in Wisconsins Specialty Crops  Environmental Impacts. October 28, Madison, WI. Invited Speaker.