Hello.
A probable Diplodia located on a small Pistacia branch, probably Pistacia terebinthus.
Ascomata in the form of blackish erumpent grains, bursting through the bark, between 0.6 and 0.7 mm in diameter.
Short, hyaline conidiogenous hyphae, producing brown-pigmented conidia, with a very marked central septum in mature conidia, with a slight constriction in this septum and measurements in water of:
(22.6) 23.1 - 29.3 (31.3) × (9.9) 10.2 - 14.3 (14.8) µm
Q = (1.8) 2 - 2.67 (2.7) ; N = 20
Me = 26.9 × 11.7 µm; Qe = 2.3
Based on the microscopic data obtained, everything seems to point to Diplodia. Among the Diplodia species on Pistacia, we have Diplodia insularis, with non-septate conidia; Diplodia pistaciicola, for which I have been unable to find any information online; and Diplodia pistaciae, for which I have only been able to find a single image without any scale, along with an Alamy drawing, which I have added to my images.
I don't know if anyone here has any additional information to confirm or deny the species.
Thank you very much in advance.
Best regards.