In the last years, an insect is detected on the foliage of Quercus ilex trees in Algeria (North-East region). Dryomyia lichtensteini F.Löw, 1878 (Diptera: Cecidomyidae), The Chronology of Gall’s emergence of Dryomyia lichtensteini and its field infestation rate were followed since 2014, in evergreen oak plantation in the Algerian North-East Region (Setif). Some statistical methods of Gall’s emergence of this pest and its effect at Quercus ilex’s Sanitary state are reviewed and discussed. For each study area (North-South-East-West), 10 trees were marked. 30 leaves of each tree were removed, so it is 300 leaves for each site, which were analyzed. This study is based on the number of galls observed. In order to highlight the degree of attack of pests. The outputs were made from November 2014 to November 2016, due to one output per month.
Keywords: Quercus ilex, Cecidomyidae, gall inducers, Algeria