In November 2023, lemon trees (Citrus limon) showing black root rot, defoliation and mortality were observed in Wadi El-Natroun, Al-Behera governorate, Egypt (30° 59′ 16.5″N, 30°29′11.7″E), with a disease incidence of 25% (Fig. 1). 

Yellowing and dieback of the trees started from one side then developed to cover the whole tree. The diseased trees showed gummosis with a large quantity of exudates oozing out along the tree branches and trunk before death of the trees. Black, distorted and partially decayed roots were observed. Diseased roots were cut into small sections (1 cm), surface sterilised and transferred onto potato dextrose agar (PDA) plates supplemented with chloramphenicol (50 mgl−1). After incubation for three days at 20°C, the fungal colonies were purified using the hyphal tip technique onto new PDA plates. Colonies appeared similar to each other. The mycelium of one colony (SY25) had a cottony appearance with some scattered dense tangles, turning black with age, radiating, and covering the full plate after three days at 25°C in the dark (Fig. 2). Sclerotia-like structures formed on the aerial hyphae after two days. These were subglobose to irregular, dark brown turning to black at maturity, and measured 78.0-205.2 × 60.8-194.1 µm. Black ostiolate protoperithecia formed on the mycelia when cultured on modified corn meal dextrose agar medium (Fields & Grear, 1966). These measured 350–415 × 280–300 µm (Fig. 3). The phenotypic description of isolate SY25 was consistent with Sordaria sclerogenia (Fields & Grear, 1966).