Between 2022 and 2024, diseased twigs and branches of Citrus clementina and Citrus sinensis trees exhibiting symptoms of dieback, cankers, bark cracking and gummosis were collected randomly from three major citrus-growing areas in Morocco: 200 samples from the Eastern region (Berkane), 150 samples from Beni-Mellal-Khenifera, and 150 samples from Rabat-Salé-Kénitra. 

Small tissue fragments (c. 3 × 3 mm) from leaves and transverse sections of twigs and branches were aseptically excised and surface-sterilized by immersion in 70% ethanol for 3 min, followed by 2% sodium hypochlorite (NaClO) for 3 min. Samples were then rinsed three times with sterile distilled water and air-dried on sterile filter paper. Subsequently, the disinfected tissues were placed onto potato dextrose agar (PDA) plates supplemented with streptomycin sulphate (150 µg/mL; Sigma-Aldrich, USA) and incubated at 25°C for 7 days. 

Pure cultures were obtained by transferring single hyphal tips to PDA amended with streptomycin antibiotic. Fungal colonies morphologically resembling members of the family Botryosphaeriaceae were recovered consistently from all wood fragments cultured on PDA. The initial colonies appeared white, exhibiting rapid growth, a dense, woolly texture, and abundant mycelium. As the colonies matured, the mycelium, initially white, gradually developed a grey-brown to black pigmentation. 

Conidia produced by these isolates were initially hyaline, becoming dark grey upon maturation. They were aseptate, ovoid in shape, with moderately thick walls, and measured 22.6–23.3 × 9.5–10.5 µm. Other isolates obtained were characterized by colonies bearing a prominent aerial, cottony mycelium and a centrally originating dark pigmentation. The conidiogenous cells observed in these colonies were cylindrical, hyaline and smooth-walled, measuring 8–14 × 3–7 µm. The conidia were brown, with subcylindrical, rounded apices, and exhibited a single septum at early developmental stages, measuring 16–26 × 7–12 µm.