Arkoola nigra produces an extensive, branching, dark brown to black mycelium on the surface of soybean leaves, branches and pods. Circular to oval leaf spots, 1-10 mm in diameter, are grey to brown with a distinct thin dark margin. Occurring on either side of the leaf, spots may coalesce and cause the leaf to tear easily, or a 'shot-hole' effect may appear when the centers of spots fall out. If disease is severe, yellowing develops around and between the lesions. On pods and stems, the spots are oval-elongate and darker. Pods can be shrunken, containing discolored seed below the lesion. Webs of dark mycelium can also appear on fallen parts and crop residue as well as on the soil under and around them.