Biostimulants represent one of the most promising innovations in olive growing in many ways. To stimulate natural plant defense-very topical in the era of Xylella fastidiosa subsp. pauca, already deepened (1,2)-as well as reduce inputs and optimize resource utilization.
Experimental studies on products based on algae, microalgae and florotannins-as well as others, of animal origin-have shown appreciable results in terms of yield and production quality (olives and extra virgin olive oil).
This approach is also particularly useful for the purposes of converting olive groves to the organic farming system. And more generally to the maintenance and development of agroecology, on this and other crops, (2) under conditions of economic sustainability.
Biostimulants, legal framework
Legally speaking, biostimulants qualify as plant protection products. They are therefore governed by Regulation (EC) 1107/2009 as amended. (3)
‘Plant biostimulant is any product that stimulates plant nutritional processes, regardless of its nutrient content, with the sole purpose of improving one or more of the following characteristics of the plant or plant rhizosphere:
(a) nutrient use efficiency;
(b) Abiotic stress tolerance;
(c) qualitative characteristics;
(d) availability of nutrients confined in the soil or rhizosphere.’ (EU Reg. 2019/1009, Article 47.1.2. See footnote 4)
The nature of biostimulants can be microbial-such as mycorrhizal and non-mycorrhizal fungi, bacterial endosymbionts (e.g., Rhizobium) and non-microbial (e.g., algae extracts, microalgae. See notes 2,5,6,11,12). Their properties are mainly attributed to amino acids, peptides, vitamins, enzymes, substances with hormone-like action (e.g., phytohormones), antioxidants and/or minerals. They must in all cases meet certain requirements for composition, functionality, purity (i.e., absence of or compliance with certain residue thresholds), and information to professional users and/or consumers. (5)
Biostimulants in Italian olive growing.
The use of animal-derived biostimulants was tested on two groups of young olive trees, at the age of 1 year(cultivar Leccino, in pots) and at the age of 2 years(cultivar Moraiolo, immediately after transplanting in the field, in Umbria). Recording in both cases:
– the acceleration of growth of treated plants, in comparison with the comparison groups, until the completion of vegetative development,
– The increased development of biomass in all parts of the tree (roots, stem, leaves, shoots). The trial was favorably concluded, noting the significance of the results in reducing time in the nursery and speeding up entry into production, promoting the preservation of the vegetative-productive balance. (7)
Algatan on olive trees affected by Xylella
The compound of algae, microalgae and tannins developed by Algatan has proven to be very effective in strengthening olive plants and drastically reducing the damage caused by the bacterial Xylella fastidiosa sub. pauca, an agent of olive tree desiccation. (2)
Xylella
has been established in Apulia since 2013 and has infected more than 8,000 hectares of olive groves. (8) However, authorities have completely overlooked the effective conservation solutions demonstrated by biostimulants from Algatan and the Experimental Crop Center of Aosta (mycorrhizae. See footnote 1)
Biostimulants in olive groves in Spain and Tunisia
A biostimulant with algal extracts-used in Spain on two superintensive cultivars (Alberquina and Koroneiki)-has shown the ability to replace inorganic fertilizers while preserving and even improving yields. In addition to stimulating defense against biotic and abiotic stresses, as well as promoting environmental sustainability of agricultural production. Its ability has been attributed to the mix of polysaccharides, polyphenols, vitamins and phytohormones. (9)
Foliar administration of a mineral-based biostimulant in Tunisia, on the cultivar Chemlali, in turn showed significant improvements in oil olive quality. Measured through the various parameters of:
– lipid profiles. Increasedoleic acid, and oleic/linoleic, monounsaturated/polyunsaturated ratios,
– polyphenols. Increased content of total polyphenols. (10)
Algae extracts on Sinai olive trees
Foliar treatment with a biostimulant based on extracts of microalgae(Scenedesmus acutus, Coelastrum proboscideum) and three types of seaweed, tested in Sinai, has shown the ability to improve the performance of olive trees of the Koroneiki variety on calcareous soils with high salinity.
Spraying the product at low concentrations (0.1 percent)-at the three stages of initial growth, flowering and fruit ripening-has proven to be the best method to increase growth, yield, fruit and oil quality. On a cultivar tested under decidedly adverse soil and climatic conditions. (11)
Interim conclusions
The use of biostimulants, especially those of algal origin, has shown great promise for accelerating entry into production and increasing the quality-quantity production of treated plants. Environmentally and agriculturally friendly, thanks in part to the low dilutions required.
Further trials are still needed to evaluate and substantiate the action of these products on other cultivars and geographical settings. In the perspective of a true ecological transition, which can only come with the organic production method, even in olive growing. (12)
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) Dario Dongo, Marina De Nobili, Guido Cortese. Xylella Fastidiosa, the solution at hand. GIFT(Great Italian Food Trade). 2/23/19, https://www.greatitalianfoodtrade.it/idee/xylella-fastidiosa-la-soluzione-a-portata-di-mano
(2) Dario Dongo, Andrea Adelmo Della Penna. Animal husbandry, algae and microalgae to prevent antibiotic use. Algatan. See paragraphs Microalgae for agriculture, Algatan in agriculture. GIFT(Great Italian Food Trade). 9.9.20, https://www.greatitalianfoodtrade.it/progresso/zootecnia-alghe-e-microalghe-per-prevenire-l-uso-di-antibiotici-algatan
(3) Reg. EC 1107/2009 concerning the placing of plant protection products on the market and repealing Council Directives 79/117/EEC and 91/414/EEC . Consolidated text as of 3/27/21 at https://eur-lex.europa.eu/legal-content/IT/TXT/?uri=CELEX%3A02009R1107-20210327&qid=1620996789608
(4) Reg. EU 2019/1009 Establishing rules concerning the making available on the market of EU fertilizer products, amending Regulations (EC) No. 1069/2009 and (EC) no. 1107/2009 and repealing Regulation (EC) No. 2003/2003. Consolidated text as of 6/25/19 at https://eur-lex.europa.eu/legal-content/IT/TXT/?qid=1620996476594&uri=CELEX%3A32019R1009
(5) Du Jardin (2015). Plant biostimulants: Definition, concept, main categories and regulation (review). Sci. Hortic. 196:3–14, doi:10.1016/j.scienta.2015.09.021
(6) Battacharyya, D., Babgohari, M. Z., Rathor, P., & Prithiviraj, B. (2015). Seaweed extracts as biostimulants in horticulture. Scientia Horticulturae, 196, 39-48. doi:10.1016/j.scienta.2015.09.012
(7) Leen Almadi, Andrea Paoletti, Nicola Cinosi, Elissa Daher, Adolfo Rosati, Claudio Di Vaio and Franco Famiani. (2020). A Biostimulant Based on Protein Hydrolysates Promotes the Growth of Young Olive Trees. Agriculture 10:618, doi:10.3390/agriculture10120618
(8) Kottelenberg et al. (2021). Shape and rate of movement of the invasion front of Xylella fastidiosa spp. pauca in Puglia. Nature Research 11:1061, https://doi.org/10.1038/s41598-020-79279-x
(9) Hernández-Hernandez et al. (2019). The Use of Biostimulants in High-density Olive Growing: Quality and Production. Asian Journal of Advances in Agricultural Research 10(4):1-11, doi:10.9734/ajaar/2019/v10i430034
(10) Zouari et al. (2020) Olive oil quality influenced by biostimulant foliar fertilizers . Brazilian Journal of Biological Sciences 7(15):3-18, https://doi.org/10.21472/bjbs(2020)071501
(11) El Migeed et al. (2018) Response of olive trees (cv. Koroneiki) to algae extract sprays and its impact on growth and productivity under saline conditions. Middle East Journal of Agriculture Research 7(1):34-40, http://www.curresweb.com/mejar/mejar/2018/34-40.pdf
(12) Chiaiese et al. (2018). Renewable Sources of Plant Biostimulation: Microalgae as a Sustainable Means to Improve Crop Performance. Frontiers in Plant Science 9:1782, doi: 10.3389/fpls.2018.01782
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
