What else needs to be considered in plants?

What else needs to be considered in plants?

By now, having asked all kinds of questions and in some cases consulting others or sending in samples for analysis, a good diagnostician asks for the last time, “What else might I be missing?” You should stop and reconsider everything you have learned thus far. Does it all add up to support a good diagnosis?

Emerald ash borer provides a good example of the value of stopping to reconsider everything before making a diagnosis. Prior to the discovery in 2002 that this non-native beetle was living in the United States, people were certainly aware that ash trees were dying. However, correctly diagnosing a plant problem that is not known to occur is without doubt the most difficult diagnosis to make. We tend to focus on the “known.”
It was known that a number of tree-killing diseases could occur on ash, including ash yellows and Verticillium wilt. Ash trees were generally considered “tough trees” and they were often planted in challenging sites such as in parking lot planters, or along street curbs. It was no surprise that many died. Finding holes in these trees was also no surprise since it was well known that several native insect borers target stressed ash trees.
Reconsidering Question #4, “What do you see that looks abnormal,” along with Question #6, “What exactly do you see” would have been helpful in disclosing the presence of emerald ash borer. Native borers produce round or oblong adult emergence holes; emerald ash borer produces distinctly “D”-shaped holes. Sadly, it is now known that emerald ash borer was living in the United States at least 10–15 years prior to its discovery; prior to a correct diagnosis. “What else?” should always be a nagging question on a diagnostician’s mind.