ARS | Publication request: Glucosinolate content and nematicidal activity of Brazilian wild mustard tissues against Meloidogyne incognita in tomato

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 26, 2010
Publication Date: November 19, 2010
Citation: Oliveira, R.D.L., Dhingra, O.D., Lima, A.O., Jham, G.N., Berhow, M.A., Holloway, R.K., Vaughn, S.F. 2010. Glucosinolate content and nematicidal activity of Brazilian wild mustard tissues against Meloidogyne incognita in tomato. Plant Soil. 341:155-164.

Interpretive Summary: Biological control of pests in agriculture is a method of controlling pests (including insects, nematodes, weeds and plant diseases) that relies on natural biochemicals, and can be an important component of integrated pest management (IPM) programs. Wild mustard, although an invasive weed species in Brazil, may be harvested for its seed which contains a high oil content that can be used to produce biodiesel. After pressing the oil out of the seed, the residual seedmeal contains compounds which have been previously shown to degrade in the presence of water to form chemicals toxic to plant parasitic nematodes. We found that the efficacy of the wild mustard seedmeal against several species of plant parasitic nematodes was correlated to the levels of the principal degradation compound, allyl isothiocyanate. This research indicates that application of wild mustard seedmeal could be an effective biocontrol treatment for nematodes.

Technical Abstract: 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.