Department “Plant Pathology and Chemistry” was established in 2005 after the unification of Departments “Pathology and Plant Protection” and “Chemistry and Biochemistry”.

The Department “Pathology and Plant Protection” was established in 1947 under the name “Forest protection”. The first head of the Department was Prof. Dimitar Stefanov, who made significant contribution to the development of the university as Vice Chancellor (1953–1957) and later as Chancellor (1957–1958) of Higher Institute of Forestry. Head of the Department after 1962 was Prof. Bonko Zashev. In 1965, the Department joined with Department “Wildlife Management” and it was renamed “Forest Protection and Wildlife Management”. Prof. Nikola Botev was head of the Department after 1974. For different periods of time head of the Department were Assoc. Prof. Anelia Pencheva and Prof. Alexander Tashev as well. During these years, Prof. Georgi Ganchev and Assoc. Prof. Ivanka Daskalova also gave significant contribution to the development of forest protection and ornamental plants protection as long term lecturers. In 1995, both Departments were divided and head of the newly established Department “Plant protection” was Assoc. Prof. Dinko Ovcharov, and after the end of 1995 – Assoc. Prof. Stefan Mirtchev. Due to the association of the Faculty of Ecology and Landscape Architecture and Faculty of Agronomy the lecturers Prof. Yordanka Stancheva Assoc. Prof. Georgi Trenchev, Assoc. Prof. Maria Todorova-Panayotova and Assoc. Prof. Rumen Tomov joined the Department during 1999–2003. At the end of 2003 the Faculty of Agronomy was separated again and the Department was divided into: Department of “Pathology and Plant Protection” as part of Faculty of Ecology and Landscape Architecture and Department “Plant Protection” as part of Faculty of Agronomy.

Department of “Chemistry and Biochemistry”, originally named “Chemistry”, was established in 1953 by Prof. Buko Ronkov, who was its head until 1974. During the period 1965–1974 the Department existed under the name “Chemistry and Physics”. From 1974 to 1994 the Department of “Environmental Protection” was also part of this Department, which was subsequently divided again (1994). The newly formed Department was called “Chemistry and Biochemistry” and governed by Assoc. Prof. Viktoria Lachkova until 2000. Lots of associates contributed with their work to the progress of the Department: Assoc. Prof. Anka Parusheva, Assoc. Prof. Lilia Staeva-Bozhova, Prof. Nadka Ignatova, Assoc. Prof. Kristina Hadzhiivanova, Assoc. Prof. Lyudmil Antonov, Assist. Prof. Petar Velev, Assist. Prof. Anzhelina Georgieva.

The Department of “Plant Pathology and Chemistry” exists as structure, known up to nowadays, since 2005, when the union of the Department of “Pathology and Plant Protection” and “Chemistry and Biochemistry” took place. The first head of the newly established unit was Assoc. Prof. Stefan Mirtchev, followed by Prof. Ivan Genov (2012–2016). During this period part-time lecturers were Prof. Ivan Glavchev, Assoc. Prof. Viktoria Lachkova, Chief Assist. Prof. Petia Parvanova and Chief Assist. Prof. Vishnya Stoyanova.