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 evaluatein vitropine (Pinus sylvestrisL.) 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, severalin vitroexperiments 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 cactorumandMycosphaerella fragariae.Radial growth tests showed that coniferous bark extracts inhibit mycelial growth ofB. cinerea, C. acutatum, P. cactorumandM. fragariae. Extracts had the highest antifungal effect onB. cinereatwo and five days after inoculation (p< 0.05). Bark extracts can reduce the sporulation ofB. cinerea, C. acutatumandP. cactorum.

The development of new environmentally friendly plant protection products against grey mould disease (caused by Botrytis cinerea Pers.) was started in 2010. In the Latvian State Forest Research Institute “Silava”, production of coniferous biomass extracts using different solvents for extraction was performed. During 2010-2011, several laboratory investigations were carried out in the Institute of Biology, University of Latvia. Effectiveness of pine (Pinus sylvestris) and spruce (Picea abies) biomass extracts against Botrytis cinerea was tested. On the basis of coniferous extracts, 11 formulations were created and characterised. The effect of the formulations on mycelial growth of B. cinerea test cultures was tested using the fungal radial growth test. All formulations had inhibitory effect on mycelium growth (inhibition rate over 50%) at concentration 20 g L-1 in medium. The impact of formulations on plants after spraying was evaluated using in vitro propagated strawberry plants. Chlorophyll content and chlorophyll fluorescence were estimated. Extracts did not show negative effect on the chlorophyll content and fluorescence of strawberry leaves. Field investigations on strawberry (Fragaria × ananassa Duch.) ‘Senga Sengana’ and primocane raspberry (Rubus idaeus) ‘Gerakl’ were conducted in the Pûre Horticultural Research Centre in 2011. None of tested the coniferous biomass extract formulations showed higher effectiveness than fungicide Signum® (pyraclostrobin 6.7%+ boscalid 26.7%, BASF).