Diversidade de agentes de biocontrole utilizados no norte de Mato Grosso

Abstract

The ways of managing pests and diseases in field have been gradually changing, encouraged by consumer appeal, the effectiveness, and benefits of inserting microorganisms such as Trichoderma spp., Beauveria spp. and others, which serve as biocontrol agents, and help in the dynamics of the soil microbiota of crops. The objective of this work was to demonstrate the diversity of microorganisms that are used as biocontrollers in the northern region of the state of Mato Grosso. For this, biological product samples received at the Plant Diseases Diagnosis Clinic of the Federal University of Mato Grosso, Sinop campus were analyzed, which were analyzed in the Microbiology and Phytopathology laboratory. Samples of biological products were serially diluted, a process that consists of adding 1 mL of the product to be analyzed in previously sterilized test tubes containing 9 mL of saline solution (0.85%) and Tween 80 (0.05 %), obtaining the concentration 10-1 . After stirring this tube, 1 mL of the solution was transferred into a new test tube, and this process was repeated until reaching the desired analysis concentration, which varies between 10-5 and 10-8 , depending on the sample. After the serial dilution, 100 μL of the suspensions obtained were transferred to plates with the ideal culture medium for the analyzed microorganism, and this aliquot was spread on the surface of the culture medium through circular movements, with the aid of a Drigalsky loop. The analysis was performed in triplicate for each chosen dilution, which were placed in B.O.D. at 25± 2°C for fungi and ±37± 2°C for bacteria until microorganism colonies form (24-48h). After growth, colonies were counted per plate and colony forming units (CFU) were estimated per mL of solution, which served as a source for the estimate. 98 samples were received, predominantly from "on farm" biological products, which were received between the years 2020 and 2022, from various municipalities in Mato Grosso, such as: Sorriso, Cláudia, Feliz Natal, Marcelândia, Sinop and Nova Ubiratã. Among the years analyzed, 2021 stood out with the highest number of products received, totaling 56 samples. The microorganisms that stood out with the highest percentage of reception were the fungi: Trichoderma spp., Beauveria bassiana and Metarhizium anisopliae, among the bacteria, Bacillus subtilis, Pseudomonas spp. and Azospirillum sp.