Throughout the investigative process, eliminate the minor factors to discover the primary cause. For example, although phosphorus deficiency symptoms can indicate a need for phosphorus fertilization, the deficiency can be caused by root pruning insects, poor drainage, low pH, low temperature, or chemical damage. Applying the wrong treatment will cost your client money and may still not solve the problem. There will be times when it is not economically feasible to correct the problem, or it may be too late in the season to correct the problem economically. In these cases, use the opportunity to teach your client how to prevent the problem in the future.
New problems do develop occasionally.
In recent years, three problems were originally misidentified. Dectes stem borer was mistaken for soybean lodging due to a lack of potassium fertilizer. Soybean cyst nematode infestations were confused with potassium deficiency problems. Soybean severe stunt disease was confused with 2,4-D injury. New problems can often look very similar to old problems.