Articles

ACTIVITY OF CHESTNUT TANNINS AGAINST THE SOUTHERNROOT-KNOT NEMATODE MELOIDOGYNE INCOGNITA


Abstract


Studies on the effects of tannins on plant-parasitic nematodes are few. A new formulation of a hydrolysable tanninextracted from chestnut (SaviotaN®) was tested for efficacy in controlling Meloidogyne incognita. Therefore, in vitro andpot experiments on tomato were performed to investigate the nematicidal activity of tannin aqueous solutions at differentconcentrations on M. incognita. In the in vitro experiment the following concentrations of tannin at 0.30, 0.40, 0.50, 0.75,1.00, 1.25, 1.50 g L−1 were tested for their effect on the nematode. The second-stage juveniles (J2s) immobility increasedwith increasing concentration and exposure time. All tested tannin concentrations were effective to reduce viability fromabout 45 to 70% after 10 days of exposure, in comparison to the treated and untreated controls. The immobile J2s recoveredtheir mobility over time after rinsing and transferring them in water, showing a nematostatic activity of tannins. In the potexperiment, tannins, as aqueous solutions at rates from 0.30 to 1.50 g L−1, were applied to soil at three different applicationtimes (1: only at transplant; 2: at transplant, two weeks after transplant and repeated every seven days; 3: at transplant andtwo weeks later). The activity of tannins was compared to treated and untreated controls. Tested rates mostly repeated wereeffective to control nematode attack in comparison to untreated control. The height of treated plants was not significantlyinfluenced by the different applied rates of tannins, whereas nematode population density and root galling index wereaffected by repeated application times. No visual symptoms of phytotoxicity were detected. The use of SaviotaN®appearspromising for the control of M. incognitain sustainable agriculture of short-term crops and/or when nematode populationdensities are low and as a supplement to other chemical treatments.

Keywords

Root-knot nematode; Meloidogyne incognita; Tomato; Hydrolyzable tannins; SaviotaN®

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