Impact of pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.) bark extracts on important strawberry pathogens

Phytopathogenic fungi induced considerable economic losses in strawberry production industry; therefore, more attention should be paid to development and implementation of preventative treatment that is environmentally friendly. Coniferous trees produce a wide variety of compounds, such as terpenoids and phenolics. Several studies are known on fungicidal activity of different components of coniferous tree bark. The aim of this study was to evaluate in vitro pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.) bark ethanol extracts impact on pathogenous fungi causing diseases of strawberries. Products of processed pine (Pinus sylvestris) and spruce (Picea abies) bark were tested. During 2011 to 2013, several in vitro experiments were carried out to test the effectiveness of pine and spruce bark extracts against various phytopathogenic fungi isolated from strawberries: Botrytis cinerea, Colletotrichum acutatum, Phytophthora cactorum and Mycosphaerella fragariae. Radial growth tests showed that coniferous bark extracts inhibit mycelial growth of B. cinerea, C. acutatum, P. cactorum and M. fragariae. Extracts had the highest antifungal effect on B. cinerea two and five days after inoculation (p < 0.05). Bark extracts can reduce the sporulation of B. cinerea, C. acutatum and P. cactorum.