EFEITO DE FUNGICIDA QUÍMICO E BIOLÓGICO ASSOCIADOS A APLICAÇÃO DE EXTRATO DE ALGAS NO FEIJOEIRO-COMUM

Abstract

Common bean (Phaseolus vulgaris L.) is one of the main crops produced in Brazil and worldwide. Among the limiting factors for bean cultivation are diseases, especially those caused by soil-borne pathogens, such as white mold. Many products used in the management of this disease ca impact the development and yield of the crop, but this effect is not yet widely studied. Thus, the objective of this study was to evaluate the effect of integrated white mold management using chemical and biological products associated with an organic carbon source in the development and yield of common bean. The experiment was conducted in a completely randomized design in a 4 x 2 factorial scheme with 5 repetitions. Factor 1 was the management with chemical and biological fungicides (4 levels: Control; Biological fungicide (Trichoderma asperellum isolate BV10); Chemical fungicide (Thiophanate-methyl + Fluazinam); Biological fungicide (Trichoderma asperellum isolate BV10) + Chemical fungicide (Thiophanate-methyl + Fluazinam), and factor 2 was with and without application of seaweed extract (Ascophyllum nodosum). Two experiments were carried out, the first the crop completed its cycle and the yield parameters were evaluated, such as the number of pods, the number of grains, grains per pod, and grain weight. In the second experiment, initial growth parameters were evaluated, including the size of the aerial part and root, and fresh and dry root mass. A third experiment was conducted in which the above treatments were applied directly to the sclerotia under laboratory conditions to evaluate the effect of the products directly on the pathogen. The data obtained were submitted to analysis of variance ant test of means. The results indicate that the treatment with only the biological product (Trichoderma asperellum) associated with the seaweed extract showed a better response in terms of the number of pods compared to the chemical product used alone. Additionally, the fresh mass of the plant is influenced by the type of fungicide, showing a difference in mass gain when the seaweed extract is applied. There was no standardized colonization and germination, but it was possible to notice that in the treatments that received Trichoderma without chemical application, colonization was faster, while the control had the sclerotia germinated first.