The question of whether a particular application of herbicide on one property caused damage on another’s property requires expert testimony. When a plaintiff claims that herbicide drift caused reduced crop yields, it is not enough for an expert to opine merely that the drift caused damage to plants – the plaintiff must establish that the defendant’s application of the herbicide caused the reduced crop yield. The distinction may sound nuanced but can have profound ramifications on litigation. This is well illustrated in the Texas Supreme Court’s recent decision in Helena Chemical Company v. Cox, -- S.W. 3d --, 2023 WL 2335694 (Tex. Mar. 3, 2023), an important and highly followed case focusing on the causation requirement in cases alleging yield loss to a crop from alleged exposure to pesticides.
The plaintiffs in Cox were cotton farmers who alleged that the defendant had supervised an aerial application of herbicide that drifted onto plaintiffs’ properties and damaged their crops, causing reduced yields. A government inspector conducted a visual inspection of the damaged crops and claimed to find “markers” for the herbicide’s two active ingredients, but no lab testing was performed. The inspector also identified no “consistent pattern” or “drift pattern” of crop damage over the large area encompassing the various plaintiffs’ noncontiguous properties. Plaintiffs disclosed a slate of experts to support their allegations, but the trial court excluded the experts and granted summary judgment to the defendant. The court of appeals reversed, finding the experts admissible despite their inability to trace the alleged drift of the herbicide in question from defendants’ application site to plaintiffs’ properties.