Source: PURDUE UNIVERSITY submitted to
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
Funding Source
Reporting Frequency
Accession No.
Grant No.
Project No.
Proposal No.
Multistate No.
Program Code
Project Start Date
Sep 1, 2012
Project End Date
Aug 31, 2014
Grant Year
Project Director
Krupke, C.
Recipient Organization
Performing Department
Non Technical Summary
This project originated with reports of dead honey bees in Indiana at corn planting time. Our initial experiments to find the cause of these observations highlighted a previously unknown route of exposure for honey bees to neonicotinoid insecticides used in seed treatments - the talc exhaust produced by planters. The magnitude of corn and other annual cropping systems using treated seed (over 200 million acres each year), combined with the mobility of this exhaust and the extremely high toxicity and persistence of neonicotinoids create a situation where the margin for error in terms of honey bee exposure is very low. Using field experiments combined with existing land use, weather and apiary location data we will quantify the area potentially affected by talc exhaust and provide stakeholders across 4 states with this information via the platform. This site is already familiar to both crop producers and beekeepers.
Animal Health Component
Research Effort Categories

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
Goals / Objectives
Most annual crops planted in the United States are coated with neonicotinoid seed treatments, including virtually all corn. Corn alone accounts for over 90 million acres of cropland annually, the vast majority of which is in the North Central region. Neonicotinoid insecticides are highly toxic to honey bees and recent research investigating honey bee kills near corn fields at planting time has demonstrated several potential routes of exposure for honey bees near agricultural plantings. We plan to build on published work by focusing directly on a key mechanism for honey bee exposure - the movement of waste talc produced during planting. We will accomplish this using field experiments in production fields that will enable us to quantify the spread of exhaust talc beyond the planting field. We will then combine this information with data that are currently available online or published that reflect land use patterns (NASS-USDA website, includes high-resolution data describing where crops are planted annually), where honey bees are found (, and published estimates of honey bee foraging distances. These data will then be used to determine the level of risk to honey bees in areas near plantings of treated seed, across four midwestern states
Project Methods
OBJECTIVE 1: QUANTIFICATION OF PESTICIDE LEVELS SURROUNDING FIELDS AT PLANTING Our previous research indicates that talc exhaust from planting equipment is highly toxic. To put the figures in Table 2 in perspective, the levels of clothianidin found in the talc produced during planting of "Commercially treated seed 4" are equivalent to 700 000 times the contact LD50 for honeybees. It is unlikely that any forager passing behind this planter would survive long enough to return to the hive. The more relevant question is how these concentrations change as a function of distance from the point source (i.e. the planter). To quantify this, it is useful to think of the talc plume as a form of spray drift. Pesticide drift is a long-standing concern for agriculture, but this topic has not been a concern with seed treatments. In fact, the lack of drift is often cited as a benefit of this method of insecticide application (15). To characterize the rate of drift of talc exhaust during corn planting, we will work in production fields, using commercially-treated seed. The grower/cooperators we will be working with use air planters to plant seed. We will use four fields in each year of the study. These fields are all located within 20 miles of Purdue campus, in Tippecanoe and Benton counties, Indiana. The field dimensions will vary, but all fields will be at least 10 acres in size. Along each edge of the field, we will place passive dosimeters to measure deposition of material. These dosimeters have been used in other published studies of liquid spray deposition, and consist of a 17 X 11 cm plastic lid that is screwed onto 2 cm diameter wooden dowel that is 30 cm in length. Four standard microscope slides (approx. 7 x 2 cm) are placed on top of each plastic lid. Because we are working with dust and not liquid, we will modify the methods used by other researchers slightly by treating our microscope slides with a light coating of Tangle-Trap sticky coating (Contech Industries, Grand Rapids, MI) applied using an aerosol can. This material is inert and can be used with the chemical analyses. These horizontally-oriented dosimeters will serve as a proxy for surfaces that honey bees may contact, including flower heads or the surface of their hive. We will place four dosimeters at the midpoint of each edge of the field (i.e. N, S, W, E border), moving steadily away from the field edge. One dosimeter will be placed at each field margin, with subsequent dosimeters located at 10, 50, and 100 m beyond the field edge. Dosimeters will be stored horizontally in Styrofoam "racks" and placed in a cooler for transport to the lab, where they will be frozen until analysis. Dosimeter and planter talc samples will be sent to an analytical chemist. The procedure used is a modified version of the protocol used to quantify pesticide levels in food and feed. This allows the various pesticides (incl. herbicides and fungicides) to be unambiguously identified at the parts per billion (i.e. nanograms/gram) concentration level.

Progress 09/01/12 to 08/31/14

Target Audience: Other scientists Ag industry professionals State and federal regulators Farmers and landowners Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? One post-doctoral scholar, Dr. Elizabeth Long, was funded by this project for the last 2 years. How have the results been disseminated to communities of interest? See above and previous section - primarilly via extension presentations but also via meetings with regulators and individual stakeholders. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

What was accomplished under these goals? The goal of this work is to make field crop producers and consultants aware of the hazards associated with planting treated corn and soybean seeds, while also presenting the possible benefits in terms of crop protection. Two key messages are presented to audiences: Bees are at risk: Routine, "as-recommended", planting of insecticide treated corn and soybean seeds can be harmful to bee health. All dead bees sampled during the corn planting during spring 2010 and 2011 contained traces of the seed treatment insecticides used in corn and soybeans. Seed treatment insecticides are highly persistent and move beyond the treated field - they are found in field soils over 2 years after planting, on plants visited by bees, and in planter exhaust. Bees visit corn during the pollination period and collect pollen from treated seed, which expresses neonicotinoids at low levels. Beekeepers and field crop producers must communicate so that bees can be removed or screened during the planting period. Cleaning of equipment must be done as far as possible from beehives or blooms, because contaminated talc is highly toxic. Growers are locked into a practice with no consistent agronomic benefit. No demonstrable crop protection benefit (including damage to plants and yield) attributable to seed treatments has been detected in corn or soybeans in replicated field trials throughout the state from 2011-13. These results support earlier work as well as findings of colleagues in other states. Data generated in 2013-14 demonstrate that although trace levels of neonicotinoid insecticide are found in plants throughout the season, the window of crop protection is likely to be quite limited; approximately 12 days after planting for corn and 18 days for soybeans. In light of results showing no pest management benefits in replicated field trials, seed dealers are requested to offer untreated seed as an option for field crop plantings near sensitive areas (e.g. apiaries, bee-pollinated crops). Currently, there are no options for non-organic growers interested in purchasing untreated corn seed, and approximately 80%+ of soybean seed is usually treated with neonicotinoids. Specific outcomes include: response by the registrants is led by development of novel polymers and planter lubricants that reduce the development of dust during planting. Regulators (EPA, USDA) highlighted the issue and Dr. Krupke's work in white papers that summarize the current threats to pollinators. The EPA accelerated a registration review of neonicotinoid insecticides and most recently (July 2014), has requested any data examining the yield benefits of seed treatments in corn and soybeans, as they continue their registration review. In response to Dr. Krupke's presentation on Capitol Hill in March, the USFWS is phasing out the use of neonicotinoids in their wildlife refuges (July 2014).


  • Type: Conference Papers and Presentations Status: Submitted Year Published: 2014 Citation: Long, E. Y., J. D. Holland, B. D. Eitzer, and C. H. Krupke. The planted field and beyond: tracking perilous particles to identify risks in the landscape for foraging honey bees. Oral presentation. Entomological Society of America Meeting. Portland, OR. 2014.

Progress 09/01/12 to 08/31/13

Target Audience: Corn and soybean growers Seed and ag-chem dealers Regulators Beekeepers Other research scientists Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Training of post-doctoral associate (Elizabeth Long) who is leading the analysis effort. How have the results been disseminated to communities of interest? Presentations at Indiana CCA meeting, Minnesota private applicators, and Entomological Society of America. What do you plan to do during the next reporting period to accomplish the goals? Complete analysis and mapping of hive locations, publish results of study, integrate results with Driftwatch site and generate extension resources that summarize findings.

What was accomplished under these goals? We have completed data collection from farm fields and analysis of all dust deposition data. We are currently mapping hive locations against corn field and corn drift data using USDA-NASS database and We anticipate publishing this work in spring 2014.


  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: 2013 Annual Meeting of the Entomological Society of America
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: 2013 Indiana Certified Crop Advisors Annual Meeting