Glucosinolate content and nematicidal activity of Brazilian wild mustard tissues against Meloidogyne incognita in tomato

The wild mustard (Brassica juncea L.), an invasive weed of winter crops in Brazil, was evaluated for glucosinolate content of its plant tissues and nematicidal activity of its dry leaf meal (LM), whole seed meal (WSM) and hexane defatted seed meal (DSM) against Meloidogyne incognita on tomato plants. Sinigrin was the major glucosinolate in LM, WSM and DSM, occurring at concentration of 0.11, 12.2 and 21.9 mg/gdw, respectively. Allyl isothiocyanate (AITC) was the major degradation product and its concentration was highest in DSM followed by WSM and LM. The number of galls, egg masses and eggs on tomato plants was reduced by over 90% by amending soil with 1.6% LM, 0.2% WSM, or 0.05% DSM. Exposure to the volatiles from the amended soils reduced egg eclosion. The soil amendment with LM, WSM and DSM killed the second stage juveniles of M. javanica, M. enterolobii (=M. mayaguensis) and Heterodera glycines. The efficacy of the LM, WSM and DSM for nematode suppression was related to the amount of AITC released in soil.