IntroductionFruit production is an important branch of horticulture, as fruits have been used not only for nutrition but also to meet personal and social needs (Ercisli et al., 2008). Drupe production in countries around the world, including Turkey, has important potential. Turkey ranks 1st in the world in apricot production with annual production at 985,000 t, Italy ranks 2nd with 266,372 t, and Algeria ranks 3rd with 256,890 t. In terms of almond production, the USA ranks 1st with 1,029,655 t, and Turkey ranks 5th with 90,000 t. China ranks 1st in plum production with 6,804,399 t, and Turkey ranks 5th with 291,934 t (Faostat, 2017).Mistletoe (Viscum album L.) is a semiparasitic plant, and it has been known to reduce the quality and yield of fruits in various parts of the world, including Turkey. Three subspecies of Viscum genus, which is categorized under the family Santalaceae of Santalales, are: V. album L., V. album L. sp. abietis (Wiesb.) Abrom., and V. album L. sp. austriacum (Wiesb.) Vollm. This semiparasite is a subtype containing chlorophyll a and b in its leaves and is (Kew, 2019) able to perform photosynthesis, as first reported by Miller (1982). Although it is capable of synthesizing its own glucose, it still requires water and nutrients from the host and generates its own metabolites during photosynthesis. The semiparasite uses the water and organic substances of the host, taken in through its haustorium from the xylem, initially weakening and eventually killing the host. Of all biological stress sources, mistletoe is considered one of the most destructive for plants (