Use of algae in strawberry management Hillary Righini 1 & Roberta Roberti 1 & Elena Baraldi 1 Received: 21 December 2017 /Revised and accepted: 9 April 2018 # Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract In agriculture, extracts from algae are used for their stimulant effects on plant vigor and productivity but little is known on their effect against fungal pathogens. However, the recent EU restriction on synthetic pesticides made the management of fungal plant pathogens difficult and greatly stimulated the research of alternative solutions to chemicals. Applications of extracts from algae can help limit disease spread in several crops and the development effective alternatives to chemical treatment in crop protection and nutrition management. In particular, for strawberry, the management of a number of serious diseases in open field and greenhouse in soil or soilless cultivation has become difficult due to recent restrictions in agrochemical use and the lack of effective alternatives. This review provides an overview of the most recent findings on the potential use of extracts of algae for strawberry management, concerning both their biostimulant effects and antifungal properties against pathogens. The existing reports on this topic show the strong potential of algae extracts application on plants both as biostimulants and bioprotectants against fungal pathogens. Further investigation is needed to fully uncover the interesting and exploitable antifungal properties of extracts from algae and to clarify the mechanism of action of extracts and singular components against pathogens. Keywords Strawberry . Algae . Biostimulant effect . Antifungal activity Introduction Algae refer to a very diverse and large group of aquatic pho- tosynthetic organisms. They include unicellular organisms such as the green alga Chlorella, and marine multicellular algae commonly named seaweeds, such as the brown alga Sargassum that can reach several meters in length. Algae are classified in several phyla among which Chlorophyta (green algae), Rhodophyta (red algae), and Ochrophyta are the major ones, with the brown algae (Phaeophyceae) being a large class of the Ochrophyta (Guiry 2012). The geographic location and season of harvest influence the composition of the algae (Black 1950; Painter 1983; Westermeier et al. 2012) and their content of polysaccharides (Rioux et al. 2007; Schiener et al. 2015). Algae also contain essential nutrients, trace of metal mixtures (Cu, Co, Zn, Mn, Mo, etc.; Cabrita et al. 2016), and plant growth regulators like auxins and cytokinins (Rayorath et al. 2008; Craigie 2011). Due to their composition, extracts from algae (EA) have long been used in agriculture to enhance soil fertility and crop productivity (Khan et al. 2009; Craigie 2011; Arioli et al. 2015). Their commercial products usually consist of liquid formulations where algae are suspended in water, acids, or alkalis (Calvo et al. 2014) upon mechanical and physical processing by low temperature, milling, or high pressure (Hervé and Rouillier 1977; Stirk and van Staden 2006; Craigie 2011; Pramanick et al. 2017). Liquid products can be applied on roots by immersion of nursery seedlings before transplantation, or to agricultural crops through soil irrigation, or spray treatments onto the leaves. These treat- ments showed beneficial effects on several crops such as to- mato, apple, wheat, strawberry, and winter rapeseed (Crouch and van Staden 1992; Basak 2008; Kumar and Sahoo 2011; Alam et al. 2013; Jannin et al. 2013). The extracts from the brown algae Ascophyllum nodosum and Ecklonia maxima were shown to be highly effective in increasing various plant parameters, e.g., vegetative and reproductive growth and yield, chlorophyll, and mineral elements content of leaves (Table 1, references therein). Besides their wide use as organic fertilizers and plant growth promoters, EA can enhance the tolerance of crops to a wide range of abiotic and biotic stresses and extend the post-harvest shelf life of fruit (Craigie 2011; * Elena Baraldi elena.baraldi@unibo.it 1 Department of Agricultural and Food Sciences, Alma Mater Studiorum, University of Bologna, Viale G. Fanin 46, 40127 Bologna, Italy Journal of Applied Phycology https://doi.org/10.1007/s10811-018-1478-2