Youssef Rouphael & Patrick du Jardin 
Biostimulants for sustainable crop production 

Part 1 Introduction and biostimulant characterization
1.Plant biostimulants: a new paradigm for the sustainable intensification of crops: Patrick du Jardin, Gembloux Agro-Bio Tech – University of Liège, Belgium;
2.Bioactive compounds and evaluation of biostimulant activity: Luigi Lucini and Begoña Miras-Moreno, Università Cattolica del Sacro Cuore, Italy; and Andrea Ertani, Università degli Studi di Padova, Italy;
Part 2 Non-microbial and microbial categories of biostimulants
3.Humic substances (HS) as plant biostimulants in agriculture: Andrea Ertani, Università degli Studi di Padova and Università degli Studi di Torino, Italy; and Michela Schiavon and Serenella Nardi, Università degli Studi di Padova, Italy;
4.Seaweed extracts as plant biostimulants in agriculture: Izabela Michalak, Wrocław University of Science and Technology, Poland; Katarzyna Tyśkiewicz, Marcin Konkol and Edward Rój, New Chemical Syntheses Institute, Poland; and Katarzyna Chojnacka, Wrocław University of Science and Technology, Poland;
5.Biostimulant action of protein hydrolysates on crops: Giuseppe Colla, University of Tuscia, Italy; Youssef Rouphael, University of Naples Federico II, Italy; Mariateresa Cardarelli, Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, Centro di ricerca Orticoltura e Florovivaismo, Italy; Luigi Lucini, Università Cattolica del Sacro Cuore, Italy; and Andrea Ertani, University of Turin, Italy;
6.Silicon as a biostimulant in agriculture: Wendy Zellner, The University of Toledo, USA; and Lawrence Datnoff, Louisiana State University Agricultural Center, USA;
7.Plant growth-promoting rhizobacteria (PGPR) as plant biostimulants in agriculture: Dongmei Lya, Rachel Backer and Donald Smith, Mc Gill University, Canada;
8.Arbuscular mycorrhizal fungi as biostimulants for sustainable crop production: Michael Bitterlich, Leibniz-Institute of Vegetable and Ornamental Crops, Germany; Louis Mercy and Miguel Arato, INOQ Gmb H, Germany; and Philipp Franken, Erfurt Research Centre for Horticultural Crops, University of Applied Sciences Erfurt and Institute of Microbiology, Friedrich Schiller University Jena, Germany;
Part 3 Innovation and practical applications
9.Designing and formulating microbial and non-microbial biostimulants: Paolo Bonini, NGAlab, Spain; Veronica Cirino, Atens Agrotecnologias Naturales S.L., Spain; Helene Reynaud, Italpollina USA, USA; Youssef Rouphael, University of Naples Federico II, Italy; Mariateresa Cardarelli, CREA, Centro di ricerca Orticoltura e Florovivaismo, Italy; and Giuseppe Colla, University of Tuscia, Italy;
10.Plant biostimulants and their influence on nutrient use efficiency (NUE): Patrick H. Brown, Douglas C. Amaral, Meerae Park, Jennifer Schmidt and Amelie Gaudin, University of California-Davis, USA;
11.Combining plant biostimulants and precision agriculture: Raffaele Casa, University of Tuscia, Italy; Davide Cammarano, Purdue University, USA; Domenico Ronga, CREA, Italy; and Giuseppe Cillo, University of Teramo, Italy;