The success of modern-day intensive farming practices is often attributed to the use of agrochemicals. However, the development of these chemicals, and specifically those which are synthetic, has led to many negative environmental consequences including the direct contamination of soil and water. Moreover, with the emergence of an increasingly frequent phenomenon of resistance among conventional pesticides and in a regulatory context for a use of pesticides more in line with sustainable development (EU “pesticide package”), biocontrol products may represent ideal candidates in the search for new eco-friendly products.

This special issue on chemistry, activity, and impact of plant biocontrol products includes a selection of papers presented at the 3th International Congress Natural Products and Biocontrol, which was held in Perpignan on September, 2016. The biennial Natural Products and Biocontrol Congress represents the most advanced research on biocontrol products’ mechanism and activity, leading the development of innovative biocontrol products in Europe and the world. More than 300 experts, from academic and industrial sectors, and scholars from 17 countries and regions worldwide attended this conference. Thirty-five oral presentations and 41 poster presentations were given during the conference. The topics include, but are not limited to:

  • Plant extract and essential oil, characterization and activity

  • Microbial metabolite, chemical characterization, activity and field evaluation

  • Microbial interaction

  • Fate and impact of biocontrol products

This congress wants to promote multidisciplinary approaches and to create cross discussions between research and industrial stakeholders, to stimulate European and international collaborations between scientists and biocontrol manufacturers for the purpose of developing innovative biocontrol products and improving practices.

Plant extract and essential oil, characterization and activity

From a total of 20 articles in this issue, 11 deal with plant-derived compounds and 8 of these articles are on essential oils, demonstrating that these volatile extracts from plants are becoming important role players in the search for new biocontrol agents. The articles focused on the control of important pests and diseases with known essential oils (Yarou et al., Benomari et al., Nguemezi Tchameni et al., Muchembled et al., and Habbadi et al.), push-pull strategies (Lamy et al.), use of distillation residues (Andreu et al.), and synergism (Ouedrhiri et al).

Microbial biocontrol mechanisms and metabolites, characterization and activity

Five research papers and two review papers deal with microbial mechanisms of biocontrol and their regulation through biotic interactions. An important focus in this special issue is made on cyclic lipopeptides (e.g., surfactin, fengycin, mycosubtilin) that are produced by several bacterial genera, but the most well-known genus remains the Bacillus genus. These compounds are produced via non-ribosomal peptides synthases (NRPS) or polyketide synthases (PKS) or hybrid NRPS/PKS pathways, and specific features of gene clusters involved in their biosynthesis are discussed in this special issue (Esmaeel et al. 2018). NRPS/PKS are modular enzymes and allow the biosynthesis of a very large diversity of molecules with potential biocontrol activities but also as pharmaceuticals (Esmaeel et al. 2018). Here, their ability to control fusariosis in ornamental bulb plants (Mihalache et al. 2018), septorisosis in wheat (Mejri et al. 2018), and fungal disease in maize in Central Africa (Kulimushi et al. 2018) are reported. These compounds like surfactin also have other important ecological roles as they contribute to the rhizosphere colonization with exopolysaccharides (Al-Ali et al. 2018). When combining different cyclopeptides, synergistic antifungal effects may exist (Mihalache et al. 2018). The biocontrol activities of secondary metabolites from other chemical families (e.g., viridin and gliovirin) produced by Trichoderma species on Phytophotora species are also described (Pakora et al. 2018). Finally, it is also debated how secondary metabolites and cooperation between bacteria in the root microbiota can affect the biocontrol efficiency of biocontrol agents and must be taken into account as much as possible (Besset-Manzoni et al. 2018).

Fate and impact of biocontrol products

Romdhane et al. and Salvia et al. develop research on environmental fate and biocontrol products’ dissipation and impact. Romdhane et al. develop research to study abiotic (i.e., photolysis) and biotic (i.e., biodegradation) processes involved in the fate of leptospermone, a natural β-triketone herbicide, by combining chemical and microbiological approaches. Salvia et al. propose a new proxy based on a new approach (called Environmental Metabolic Footprint) for the discrimination between control and pesticide-exposed sediments in order to further characterize environmental impact of conventional pesticide and biocontrol products.