Mulberry, Morus spp. (Moraceae) is naturally cultivated in Turkey, and no chemical input used during the production process. Hitherto, major and common species of insect and acari caused the economic yield and quality losses in the mulberry production have not been recorded. On the other hand, lesser mulberry snout moth, Glyphodes pyloalis (Walker, 1859) (Lepidoptera: Crambidae), considered being one of the most important pests of mulberry around the world was detected in the province of Yalova in the last week of August in 2018 for the first time. Larvae of this pest caused serious damage to leaves of white mulberry (Morus alba L., 1753), black mulberry (Morus nigra L., 1753), and weeping white mulberry (Morus alba cv. 'Pendula') (Urticales: Moraceae) whereas it has newly just occurred. This study was conducted to determine the distribution areas of the pest, mulberry species damaged, and characteristics related to some biological stages of G. pyloalis in Marmara Region (Bursa, Yalova, Kocaeli and Sakarya provinces) between 2018 and 2019. Mulberry (Morus spp.) belongs to the genus Morus of the Moraceae family involved in the Urticales order. It has been reported that the number of its species is 12-68 with one subspecies, and it has at least 100 varieties (Ercisli and Orhan 2006, Erdogan and Pırlak 2005). Mulberry is a fruit species that can grow in temperate, tropical, and subtropical climates because of its high adaptability to different climatic and soil conditions. Common mulberry species grown for its fruit are white mulberry (Morus alba L., 1753), black mulberry (Morus nigra L., 1753), and red mulberry (Morus rubra L., 1753) (Urticales: Moraceae). Mulberry grown for its leaves to feed silkworm, Bombyx mori L., 1758 (Lepidoptera: Bombycidae) is M. alba and its cultivars. Mulberry is grown in many countries of the world, and it is native to some countries. One of the mulberry species, M. alba, is native to China, Japan, Thailand, Malaysia, and Burma. Another species, M. nigra, is native to Turkey, Iran, Saudi Arabia, Syria, and parts of South Asia of Russia (Bellini et al. 2000). Turkey, one of mulberry's homeland, has 2.324 000 fruit-bearings, 353.000 non fruitbearing trees, and its production quantity is 66.647 tons (TUIK 2019). The first five provinces of Turkey in terms of mulberry production amount and numbers of the trees are given in