Phyllonorycter didymopa is a moth of the family Gracillariidae. It is known from South Africa[1] and Namibia.
The length of the forewings is 2.9–3.2 mm. Specimens were reared from mines collected in mid-January and mid-March.[2]
The larvae feed on Dombeya rotundifolia. They mine the leaves of their host plant. Later it creates a gall-like swelling near the base of the disc.