Controle alternativo com biocarvão para supressão do nematoide-das-galhas

Abstract

The increasing incidence of phytonematoids in areas cultivated for grain and seed production, vegetables and fruit growing, especially in tropical regions, draws the attention of producers and researchers, resulting in the search for control mechanisms for these pathogens. The objective of this study was to evaluate the efficiency of three biochars and a mineral based on aluminosilicates (zeolite) in the population control of Meloidogyne incognita in potted plants in a controlled environment. This thesis was structured in three chapters, initially composed of a review of the topic. In chapter I, an experiment was carried out using as alternative controls the biochars of cotton boll (BCA), swine manure (BDS) and castor bean cake (BTM); the residues of cotton boll, swine manure and castor bean cake; the mineral zeolite; comparing the efficiency with chemical (abamectin) and biological (Bacillus subtilis and Bacillus amyloliquefaciens) control, as host plant Gossypium herbaceum (cotton plant) was used. Chapter II the experiment compared different doses (0, 1, 2, 3, 4 and 5% mass of biochar/mass of substrate) of each of the biochars; chemical control and a biological control based on Paecilomyces lilacinus, and as host plant Abelmoschus esculentus (okra) was used. The experiment of chapter III used the dose of 3% (mass in grams / mass of substrate) of each of the biochars and the mineral zeolite, as a possible inducer of resistance of okra to the species M. incognita, using the split root method. Chapter I evaluated plant height throughout the experiment, root fresh mass, galls index, quantification of eggs and possible second-stage juveniles (J2s) per gram of root and total plot. In the other chapters, evaluations were made of the vegetative parameters of the plants and fruits; nematological (amount of galls, quantification of eggs per gram of root and total plot, population of J2s in the soil); in addition, electrical conductivity and pH of the substrate were measured. The swine manure, cotton boll and castor bean cake biochar, in addition to contributing to the vegetative development of the cotton plant, contributed to the suppression of M. incognita. With increasing doses of BCA and BDS, a reduction in the number of galls and eggs was observed, however, doses greater than 1% caused phytotoxicity to okra. On the other hand, BTM did not present phytotoxicity as the other biochars and, simultaneously, suppressed the gnat nematode, being able to be applied in doses higher than 1% (mass in grams / mass of substrate). The reduction in the number of galls, number of eggs and the final population of M. incognita using the broken root system method, points to a possible induction of resistance of okra when added any of the three biochars or zeolite.