J A N U A R Y 2 0 1 9 POTATO GROWER 13 tions/crops/documentation-for-sus- p e c t e d - h e r b i c i d e - d r i f t - damage/wc751.pdf. If you suspect crop damage came from a misappli- cation, check with your state’s department of agriculture to deter- mine the steps needed to document herbicide misapplication and what may be needed for a formal com- plaint. Sometimes seed tubers can have herbicides residues stored in them from the previous year, but the tuber can appear normal or have malformations such as cracking when seed is planted. Either way, look for a pattern in the field. A seed issue will cause a random or scat- tered effect of plants through the field or where that seed lot was planted. When sampling, dig up tubers that have not emerged yet. This will help you select tubers that are likely to have a higher concen- tration of herbicide and it elimi- nates the possibility of a false posi- tive (when plant leaves are exposed to herbicides) confounding results. The NDSU Extension article A1642, “Effect of Glyphosate on Potatoes” found at https://www.ag.ndsu.edu /pubs /plantsci/rowcrops/a1642.pdf explains what glyphosate looks like on plants and from seed tubers. Keep in mind there are many other things such as diseases, nutritional deficiencies and growing conditions that can cause plant injury. Determining the cause of the injury is essential. If you have question on diagnosing injury in potato, reach out to your local Potato Extension Specialist or other potato expert. Effect of picloram in potato on foliage causing twisting and cupping of leaves. Effect of glyphosate drift on field edge causing leaf chlorosis. Example of imazamox injury in potato grown for seed tuber.