“What’s Wrong with my Crop? Diagnosing Abiotic and Biotic Causes of Plant Problems”. The presentation starts with an overview of abiotic causes of problems (soil issues, nutrient imbalances, weather extremes, etc.), then I talk about diagnosing problems in the field and the things to look for that tell you whether the cause is abiotic or biotic (pests or pathogens), and I finish with some challenges in diagnosing biotic issues (symptoms that look alike, masked symptoms, etc.). I use a lot of examples from my experiences in making field calls over the years. My examples are all potato or other vegetable crops, but the information is general enough to interest forage or grain crop producers too.