Morphological Characteristics and Identification of Phytophthora Species Causing Gummosis and Root Rot of Citrus in Morocco

Abstract

the persistence of diseases such as gummosis and root rot, mainly caused by Phytophthora spp. species, notably P. parasitica and P. citrophthora. These diseases result in symptoms such as leaf wilting, reduced growth, and root rot. However, a detailed characterization of the Phytophthora species involved in these symptoms and their distribution is necessary for the implementation of effective control. The aim of the study is to characterize the Phytophthora species associated with gummosis and root rot of citrus in Morocco, as well as to select the most resistant rootstocks to replace the Sou orange, often used in Moroccan citrus orchards. Fourteen isolates of Phytophthora spp. were identified as P. parasitica and P. citrophthora. Significant differences were observed in mycelial growth and sporulation potential among isolates and culture media used. Isolates also showed variability in their pathogenicity, with some displaying high sporulation and strong aggressiveness on the leaves and branches of rootstocks. The Sour orange appears to be relatively resistant, while Citrange C35