Brassicas and their glucosinolate content for the biological control of root-knot nematodes in protected cultivation

Soil-borne diseases is a widespread problem in protected cultivation in Sicily especially after the prohibition of methyl bromide use. Secondary metabolites of some Brassica species are biofumigant able to contrast the main soil-borne agents in view to establish health and environmental friendly farming. In order to assess the effectiveness in nematodes control (Meloidogyne spp.) on tomatoes was carried out, adopting factorial design, a field trial in an representative farm of protected cultivation (Ragusa) using the flour of dry plants of Brassica juncea, Eruca sativa, Raphanus sativus and Brassica macrocarpa. The first three species were previously studied by some Authors as biofumigant, while B. macrocarpa is an endemic Sicilian wild species appearing interesting since recent scientific evidence showed high glucosinolate content in leaves, 90% represented by sinigrin, and the effectiveness of its dry leaves inserted into the soil to control root-knot nematodes in tomato crops, such as Meloidogyne spp. Tritated flour for the sinigrin content was distributed before planting (60 and 90 g m(-2)), the mean dose corresponded to the active molecules contained in the commercial formulate (Nemathorin) applied as 3 g m(-2) following the instructions. Disease index detected on the tomato roots at the end of the growing cycle (Lamberti score, 1971), although low in general, resulted in all thesis lower than the control (1.2) and the commercial formulated (0.20), whereas it was between 0 (E. sativa 60 g m(-2) and R. sativus 90 g m(-2)) and 0.13 (B. juncea 90 g m(-2)).