Resíduos da agroindústria no controle de Meloidogyne sp

Abstract

This study evaluated the potential of agro-industrial residues from the brewing (barley) and winemaking (grape) industries for controlling root-knot nematodes (Meloidogyne sp.) in tomato plants. Two experiments were conducted: one in a greenhouse and another under microcosm conditions, aiming to analyze the effects of these residues on nematode infection and reproduction, as well as on agronomic traits. Treatments included: barley residue, grape residue, a mixture of barley + grape residue, and a control (no residue addition). In the greenhouse experiment, 500 g of naturally infested substrate were treated with the residues and used to grow tomato plants for 77 days. Nematological variables were assessed, including infection parameters (mean number of galls and galls per gram of root – galls/g root), reproductive variables (number of eggs and eggs/g root), and agronomic variables (plant height, shoot mass, and root mass). In the microcosm experiment, 50 mL pots with infested soil were incubated at 25°C for 15 days after residue application. After incubation, second-stage juveniles (J2) were extracted and quantified. Statistical analysis included verifying the assumptions of ANOVA, with data transformation applied as needed. When assumptions were not met, the Kruskal-Wallis test followed by the Simes-Hockberg multiple comparison test ( = 0.05) was used. Mean comparisons were performed using Duncan’s test ( = 0.05). The grape residue treatment was the most effective, significantly reducing the mean number of galls, galls/g root, number of eggs, and eggs/g root, indicating nematicidal and suppressive effects on infection and reproduction. This effect is attributed to the presence of phenolic compounds in the grape residue, which may act directly on nematode eggs, enhance the activity of antagonistic microorganisms, and increase plant vigor. In contrast, the barley residue treatment showed no suppressive effect on infection or reproduction, with up to a 91.91% increase in the mean number of galls, and egg-related variables similar to the control. The combined barley + grape residue treatment had an intermediate effect, significantly reducing nematode reproduction (eggs and eggs/g root), but showing no significant difference in the mean number of galls compared to the control. However, infection intensity, as measured by galls/g root, was reduced. In the microcosm experiment, none of the treatments significantly affected the viability of J2, suggesting that the nematicidal action of the grape residue acts mainly on nematode eggs. It is concluded that grape residue is effective in controlling both infection and reproduction of Meloidogyne sp., while barley residue has no nematicidal effect. The combined treatment partially controls reproduction and reduces infection. Neither residue, whether applied alone or in combination, affects the viability of J2. Agronomically, only the barley residue, alone or combined, promoted improvements in plant vegetative development.