Pestalotiopsis sp., probably Pestalotiopsis palmarum: Kingdom Fungi, Imperfect Fungi (no known sexual state)
A large number of palms are listed as hosts for Pestalotiopsis palmarum, but these are in association with leaf spot diseases. Pestalotiopsis rachis blight and crown rot is primarily associated with Phoenix roebelenii.
Pestalotiopsis spp. have a world wide distribution.
Pestalotiopsis sp. can cause a typical leaf spot of numerous palm species, but on Phoenix roebelenii, it causes a serious rachis blight that often leads to a crown rot. It is reported to cause a general decline of Butia capitata and act as an opportunistic pathogen of insect-wounded Areca catechu trunks and leaf bases.
On Phoenix roebelenii, relatively large (1 inch or more) lesions develop on the rachides. These lesions may coalesce to form large areas of blighted rachis tissue (Fig. 1). Lesions may develop at the same time on the spines and even on the leaves. Of concern, however, are the lesions that develop on young leaves in the canopy on the portion of the rachides closest to the apical meristem (Fig. 3). Lesions can coalesce and expand along the rachides towards the apical meristem, eventually infecting and killing the apical meristem.