Emerging Trunk Disorders

Abstract

The last 2 years have seen increasing grower questions and reports of citrus trunk disorders.  Sometimes these reports are associated with sudden tree collapse.  In many cases, Phytophthora foot rot is initially suspected. Typically, the symptoms don’t quite match those of classic Phytophthora and the organism cannot be isolated from the lesion.  If Phytophthora spp. are present in the soil, they are well below damaging levels when sampled.  This leads to multiple questions.  Are all these trunk disorders similar?  Why are they suddenly emerging now?  What is the cause and how do we manage it?  These questions are under active investigation.