Phytoparasitic nematodes cause severe damage and yield losses to numerous agricultural crops. Considering the revision of the EU legislation on the use of pesticides on agricultural crops, control strategies with low environmental impact are required. The approach based on the use of bacteria seems particularly promising as it also helps to reduce the applied amounts of chemicals and stabilize ecological changes. This paper gives an overview of the main types of bacteria that can be used as biological control agents against plant parasitic nematodes and their interrelationships with plants and other organisms. Many experiments have given positive results of phytoparasitic nematode control by bacteria, showing possible prospects for their application. In vitro, greenhouse and field experiments have shown that bacteria can regulate the development of ecto- and endoparasitic nematodes by different modes of action. Triggering the induction of plant defense mechanisms by bacteria is seen as the optimum tool because the efficacy of bacterial treatment can be higher than that of chemical pesticides or at least close to it. Moreover, bacterial application produces additional positive effects on growth stimulation, raises yields and suppresses other pathogenic microorganisms. Commercial formulations, both as single bacterial strains and bacterial complexes, are examined.

The European legislative on the use of different control strategies against plant-parasitic nematodes, with particular reference to pesticides, is constantly evolving, sometimes causing confusion in the sector operators. This article highlights the nematode control management allowed in the C Zone of the European Union, which includes the use of chemical nematicides (both fumigant and non-fumigant), agronomic control strategies (crop rotations, biofumigation, cover crops, soil amendments), the physical method of soil solarization, the application of biopesticides (fungi, bacteria and their derivatives) and plant-derived formulations. The authors analyze the use of these strategies and substances in organic agriculture as well as in Integrated Pest Management (IPM) programs.

Five composts (C1: fresh olive pomace, straw, chicken manure, urea; C2: fresh olive pomace, lettuce residues, cow manure, straw, sawdust; C3: sewage sludge, municipal green residues; C4: grass, leaves, tree branches, soil; C5: by-product from penicillin production (mycelium), straw and sawdust) were tested in a pot experiment to investigate their short-term effect on the nematode community of a grassland soil. Composts were mixed with soil at the rates of 10, 25, 50 and 100 g (kg soil)–1 and barley was sown in each potting mixture after a 2-month decomposition period. Nematodes were extracted from each pot 5 months after barley sowing, identified at genus level and grouped into bacterial, fungal and root fungal feeders, predators, omnivores and plant parasites. Bacterial feeders, predators and omnivores were favoured by amendments with composted penicillin substrate and partly by compost from olive pomace, whereas composts from green wastes and sewage sludge suppressed these trophic groups except for predators. All compost treatments suppressed fungal feeders as well as significantly reducing the density of plant-parasitic nematodes compared with non-amended soil. The highest suppressiveness on plant-parasitic nematodes was found for the composts from urban green residues, penicillin substrate and olive pomace plus cow manure. Suppressive effect was hypothesised to be related to ammoniacal nitrogen content of the composts. Composts from fungal mycelium or olive pomace seem to be the most suitable for application in nematode management strategies due to their low impact on beneficial trophic groups.