Celery petiole lesion damage caused by insecticide

A previously undiagnosed problem, called celery petiole lesion (CPL), caused significant damage to coastal celery for several years. A 2-year study found CPL to be associated with applications of the insecticide Dibrom. The product is no longer labeled for use on celery. CPL can be mistaken for two fungal diseases, highlighting the importance of accurate diagnosis of plant problems to reduce unnecessary applications of pesticides