Fenusa pusilla Lep.'nın Atatürk Üniversitesi Kampus'u ve Erzurum'daki ağaçlarıdırma alanlarında bulunan Huş'larda zarar yaptığı bu çalışma İle ilk defa tesbit edilmiştir. Ergin ve larvanın teşhisinde yardımcı olabilecek morfolojik özellikler belirtilmiş ve bazı çizimler yapılmıştır. Böceğin biyolojisi ve zarar şekli incelenmiştir. 

The birch leaf-mining sawfly, Fenusa pusilla Lep, which is native in Europe, has been .recorded for the first time from Turkey as an important pest of of birch at the Campüs of Atatürk Universityand the landscape areas of Erzurum city. 'The external morphology having taxonomical features in determination of the adu1tand larva was deseribed and some drawings made. The sawfly overwinters at the prepural stage :Ln the soil. Theromergence of adults begin at the end of Mayand continues for about one morith. Eggs are laid ingrowing leaves of birches, and hatch in 8-10 days, larva mines between two epidermis. Larval period continues 8-21 days, but most of them become full growing larvae in two weeks. Larva drops to the ground, burrows into the soid 3-5 cm, and maikes its pupal cell. in laboratory conditions duration of prepural and pupal period is 13-21 (17) days. in natural condjtions this period is lerıger. it has two generations in the climatic conditions O.fErzurum. Tha infection is 40, 61, 32 and 16 percent respectively 1982-1985.