Controle químico e alternativo de Colletotrichum spp. provenientes de plantas de soja sintomáticas

Abstract

Anthracnose is a disease that affects any plant development stage, the seed being the main route of transmission of the disease. Thus, the objective of this study was to evaluate the effect of chemical and alternative control of Colletotrichum spp. via inoculated soybean seeds. For this, 100 soybean cultivar TMG 132, 31 inoculated with Colletotrichum, from the main producing regions of MT soybean. The seeds were treated with biofertilizers teak base (200 mL 100 kg -1 seed) and fungicidally (Piraclostrobina + Tiofanato Metílico + Fipronil) (200 mL.100 kg -1 seed), then 30 seeds were weighed and subjected to paper filter method, the "blotter test", to assess the incidence of the pathogen in these. Other 30 seeds were sown in bag containing soil-sand and kept in a greenhouse to evaluate the severity in the plant. As a control 30 seeds were inoculated with each isolate without treatments. For the incidence of the pathogen in seed evaluations are individually given with the aid of a magnifying glass, and the results were expressed as percentage of infected seeds. The variable analyzed was the presence of acervuli (%), divided into two evaluations. To assess the severity of anthracnose in the soybean plant, eight evaluations were performed visually diagrammatic. The bio formulated teak base was effective in controlling the incidence of the pathogen in seeds for isolated CL-7; SO-5; CL-5; CL-6; IT-2; IN-1; MT-1; NA-1; NM-1; NO-1; RO-1; SO-9; NU-4; BG-1; NX-1; SC-1; PN-1 and FN-1, and chemical treatment isolated SO-5; CL-3; NO-1; RO-1; SC-1; CN-2; FN-1; IT-2; MT-1; SI-7; BG-1; CL-6; CL-7 and NM-1. Severity assessment in the plant was no statistical difference in the interaction of the individual with respect to severity levels, LU-1 and MT-1 the most aggressive when subjected to treatment and the isolated biofertilizers MT-1; MA-2; CL-5 and SO-6, the chemical treatment. There was no difference in relation to the treatments examined but the chemical treatment was the best form to control for isolated LU-1. According to the results obtained, it can be appreciated that isolates showed different behavior in response to applied treatments. This change can be explained based on the selection pressure theory therefore, when subjected to a given treatment fungi seek to develop resistance to products seeking survival of the species. The chemical treatment controlled a large number of isolates, this being the best way to control.