Estudo do extrato pirolenhoso no manejo de Meloidogyne enterolobii em goiabeira.

Abstract

The meloidoginosis of guava, caused by Meloidogyne enterolobii, is currently the main problem of phytosanitary order for the culture in all producing regions of the country. The pyroligneous extract is an organic substance resulting from the condensation of vapors, consisting of 80% water and dozens of other compounds, including phenolic substances, aldehydes and organic acids, with antimicrobial potential. The test was performed in a greenhouse and in the Phytopathology Laboratory, of the Universidade Federal de Campina Grande - CCTA/UFCG, Pombal Campus-PB. The objective was to evaluate the potential of control for M. enterolobii, after the application of different concentrations of the pyroligneous extract in guava seedlings, cultivated in a greenhouse. The cultivar studied was 'Paluma', using the experimental design entirely randomized, with 11 treatments, corresponding to ten concentrations of the pyroligneous extract (0.5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50% and 100%, diluted in water) and a control with water (0.0%), with five repetitions, and the tomato cv. Santa Clara, as a positive control (Standard) (100%). The substrate was composed of soil, manure and sand, in the proportion 1: 1: 2, respectively, arranged in 5 dm³ plastic pots, with one plant as the experimental unit. Ten days after transplanting the seedlings, 5,000 eggs/juveniles were inoculated, and after ninety-six hours the treatments were applied. After one hundred and twenty days, the following variables were evaluated: number of galls (NG), egg mass (MO), eggs on the root (OR), juveniles on the soil (JS), juveniles on the root (JR), nematodes per gram of root (N/gR), reduction of reproduction factor (RFR), reproduction index (IR) and reproduction factor (RF). The variables of number of galls, egg mass and eggs in the root, were directly influenced with increasing concentrations of the treatments, reducing them, respectively. Even with parasitism in the plants, the concentrations were suppressive, with a marked reduction in parasitism and reproduction of the species.