Carla Maleita
Ivânia Esteves
Aurelio Ciancio
Yuji Oka

Plant-parasitic nematodes (PPN), “the unseen enemies” of plants, are a threat to economically important crops, affecting production, quality, and yields, with losses estimated at 173 billion US dollars/year (Elling, 2013). The top 10 PPN, based on their scientific and economic importance, include root-knot (RKN, Meloidogyne spp.), cyst (Heterodera/Globodera spp.), and root-lesion nematodes (RLN, Pratylenchus spp.), followed by other species.

For the last 50 years, PPN control has relied on the use of synthetic nematicides and soil fumigants that are rapid-acting, and specifically reliable. Nevertheless, due to environmental concerns and human health issues, most traditional nematicides have been exposed to an increasing regulatory pressure, with many products banned or withdrawn from the market. Nowadays, the adoption of control strategies based on the use of safer and selective bionematicides, biocontrol agents, cultural methods, and plant resistance is highly advisable, in order to achieve sustainable PPN control. However, some of these strategies, and their integration, are not always available or appear less consistent, compared to synthetic nematicides. In particular, microbial antagonists are selected to improve efficacy of bioformulations vs PPN, through direct application or active metabolites. However, the rhizosphere is a complex system including thousands of microbial species, whose effect is known only in part. A schematic representation of such tri-trophic (plant-nematode-antagonists) food web is given in Figure 1.

The main goal of this topic was indeed to bring together recent advances in sustainable management strategies for important PPN. The contributions include potential bionematicides, evaluation of their efficacy and mode of action (Maleita et al.); exploitation of biocontrol bacteria (Singh and Wesemael; Diaz-Manzano et al.); and a review on Nacobbus spp. management (Lax et al).