Toxicidade de compostos orgânicos voláteis de Cymbopogon nardus, Dysphania ambrosioides, Nasturtium officinale e Passiflora edulis à Meloidogyne incognita

Abstract

Volatile organic compounds (VOCs) emitted by plant organs may indicate new nematicides. Phytonematoids toxicities of volatile emissions of Plantago major, Physalis sp., Rosmarinus officinalis, Artemisia absinthiun, Ruta graveolens, Thymus vulgaris, Ocimum basilicum, Coriandrum sativum, Cymbopogon nardus, Eugenia uniflora, Momordica charantia, Ocimum gratissimum, Petiveria alliacea, Portulaca oleracea, Amaranthus viridis, Dysphania ambrosioides, Anacardium occidentale, Mentha piperita, Nasturtium officinale and Passiflora edulis had not yet been evaluated. To do this, initially, a screening was performed with the plants individually studied, through the technique developed with Supelco TM flask. The plant species that showed the highest toxicity to J2 of Meloidogyne incognita were selected for further studies. Thus, as smaller amounts (0,2 g) of P. edulis, N. officinale and C. nardus macerates emitted VOCs that caused high immobility of J2. However, only the VOCs emitted by C. nardus and D. ambrosioides caused mortalities of M. incognita. The distilled water exposed to VOCs emitted by C. nardus, D. ambrosioides and N. officinale for 72 hours caused significant immobility in J2, however, only VOCs emitted by N. officinale caused significant mortality when compared to control. After an exposure of the J2 to the VOCs emitted by the 4 most stood out plant species, an inoculation was carried out in tomatos. The number of galls and eggs after 45 days of inoculation were reducted. It was also observed reducement int the number of galls and eggs in tomatoes, through the biofumigation process, by using the macerated of the 4 plant species incorporated to the substrate inoculated with eggs of M. incognita. Gas chromatographic analysis revealed the presence of 85 molecules emitted by macerated of C. nardus, D. ambrosioides, N. officinale and P. edulis, and 5 molecules were selected for toxicity tests to, M. incognita, individually. Only 1-octanol, identified in the gas emission of N. officinale, showed nematicidal activity.