Agentes microbianos no manejo de Meloidogyne incognita na cultura do algodoeiro.

Abstract

The cotton crop can be highlighted as one of the main Brazilian commodities, generating a large number of jobs and being responsible for the migration of production areas from the Semi-arid region to the Brazilian Cerrado, as it enables growth in exports and the importation of cotton fibers through new conditions that have emerged and been facilitated, in addition to the use of irrigated areas. However, the crop is the target of several phytosanitary problems, mainly soil pathogens, among which the phytonematodes that infect the roots by impairing the absorption of water and nutrients stand out. In this sense, it is essential to search for an alternative that reduces the pathogenic effects of this pest, especially when there is a low number of cultivars with resistance to the main species of nematodes, limiting management, which affects the entire production chain. "The objective was to evaluate the reaction of nematophagous fungi (Paecilomyces lilacinus, Beauveria bassiana, Metarhizium anisopliae, and Trichoderma harzianum) in the management of the species Meloidogyne incognita. The experiment was carried out in a greenhouse belonging to the Center for Agri-Food Sciences and Technology (CCTA) of the Federal University of Campina Grande, in Pombal, PB. In a completely randomized design, consisting of four species of fungi Beauveria bassiana, Trichoderma harzianum, Metarhizium anisopliae and Paecilomyces lilacinus, with two positive (water) and negative (chemical) controls. To evaluate the effect of the biological agents, the application of the treatments was carried out on the tenth day of the germinated plants, in the amounts of: B. bassiana with 0.64 mg/pot; M. anisopliae 0.16 mg/vessel; P. lilacinus 0.16 mg/vase and T. harzianum 0.064 mg/vase, Inoculation occurred after the fifteenth day, with adjusted suspension in 4,000 eggs/juveniles of M. incognita. Sixty days after the application of the treatments, the following were evaluated: number of galls (NG); juveniles at the root (JR); egg mass (OM); nematodes per gram of root (N/gR; reproduction indices (RI); reproduction factor (RF) It is possible to notice that the use of nematophagous fungi caused inhibition of M. incognita, indicating potential in the management of the pathogen, from the lowest concentrations.