In the pivotal case of Estate of Olsen v. Agtegra Cooperative, South Dakota Supreme Court 2023, the role of the Agricultural Expert Witness was at the heart of the dispute over alleged herbicide damage to a stand of ponderosa pine trees. This case illustrates the indispensable function of expert testimony in agricultural litigation, particularly where causation hinges on scientific and technical knowledge beyond the ken of lay jurors.
Background and Facts
The plaintiffs, the Estate of Olsen, owned property in Spink County, South Dakota, where they operated a hunting business and maintained a significant stand of ponderosa pine trees. In October 2014, while guiding a hunting party, the Olsens’ son observed a crop duster spraying herbicide on adjacent farmland. Shortly thereafter, the Olsens noticed substantial damage and death among their pine trees, which they attributed to herbicide drift from the aerial application.


