Biofumigant effect of new defatted seed meals against the southern root-knot nematode, Meloidogyne incognita

In recent years, Brassica carinata defatted seed meals (DSMs) have been successfully applied as an amendment in the control of pests and soil pathogens in several countries with clear advantages for the environment and soil fertility. The effectiveness of this product is clearly linked to the release of bioactive compounds by the well-known glucosinolate (GL)-myrosinase (MYR) system. Until now, this commercial know-how has been limited to allyl-isothiocyanate, the breakdown product of hydrolysis catalysed by MYR of the GL sinigrin. Brassicaceae germplasm is an extremely wide-ranging family, considering that more than 3500 species have been classified in this family in nature, which contains around 200 different GLs. Therefore, there is a great potential for the availability of new still unexplored bioactive compounds. This study evaluated, in controlled glasshouse conditions, the effect of biofumigation on the nematode Meloidogyne incognita and that of biostimulation on tomato plants of 13 DSMs obtained from different Brassicaceae species at different levels of soil inoculation. Among the tested DSMs, the best results for all inoculations were achieved by Eruca sativa (rocket), Barbarea verna (land cress) and Brassica nigra (black mustard), whereas the other species gave either alternate results or results not different from untreated or sunflower DSM controls. All the DSMs, including sunflower, determined a clear positive effect on plant vigour. These first results open new perspectives for the application of biofumigation in plant protection and management.