Neopestalotiopsis sp. and Colletotrichum karstii, causal agents of leaf spots on camedor palm (Chamaedorea quezalteca) in Mexico

Abstract

Since 2020, camedor palm (Chamaedorea quezalteca) plantations in the Frailesca region, Chiapas, Mexico, have been affected by foliar diseases that induce leaf spot and anthracnose symptoms that reduce production, leaf quality and thus the loss of their commercial value. The objectives of this work were to identify the causal agents and to quantify the incidence and severity of foliar diseases in plantations of camedor palm. Two fungi were recurrently isolated, one from leaves with leaf spot symptoms and the other with anthracnose, both were identified morphologically and molecularly by sequencing the internal transcribed spacer (ITS5/ITS4), pathogenicity tests were performed on healthy plants where fungal conidia were inoculated, and in the field the incidence and severity of the disease were quantified with the support of a pictographic scale. The fungi identified were Neopestalotiopsis sp. in leaf spot symptoms and Colletotricum karstii in anthracnose, both pathogens reproduced the same symptoms observed in the field, by means of pathogenicity tests. Disease incidence and severity percentages were transformed to area under the disease progress curve (AUDPC), these diseases presented an annual average incidence and severity of 35.33% (AUDPC= 14180) and 39.16% (AUDPC=12885) for leaf spot, 19.5% (AUDPC= 7123) and 55.83% (AUDPC= 20380) for anthracnose, respectively.