Sensibilidad en el desarrollo de Bacillus subtilis F. Cohn al efecto de diez plaguicidas de síntesis química en condiciones controladas de laboratorio.

Abstract

This research aimed to determine the sensitivity of Bacillus subtilis to the effect of chemically synthesized pesticides under controlled laboratory conditions. The active ingredients used to determine the sensitivity of the bacteria were azadirachtin, propamocarb, dimethomorph, azoxystrobin, boscalid, cuprocalcium sulphate, difenoconazole, cartap hydrochloride, glyphosate and deltamtrin with concentrations of 0, 0.1, 1, 10 and 100 ppm. In the laboratory, a stock solution was made with doses of 100 ppm according to the concentration of active ingredient present in each product. The lower doses were obtained from serial dilutions and three replications were made for each pesticide concentration in Petri dishes. After culture medium was solidified, 50 μL of a suspension of B. subtilis with a dilution factor of 10-7 were seeded and placed in the incubator at 28 °C for 24 and 48 h. After incubation time had elapsed, the number of CFU/ml was recorded from a direct box count and with the data collected, the percentage of inhibition of each treatment regarding to the control dose (0 ppm dose) was determined. In addition, the morphological characteristics of the colonies were determined by recording of data such as: color, edge, elevation, and diffusible pigments. It was concluded that the active ingredients with the highest inhibitory effect on the development of B. subtilis were cuprocalcium sulphate and difenoconazole, whereas the products with the lowest inhibitory effect on the development of the bacteria were Azadirachtin and Propamocarb. It is recommended to carry out tests to find out the chemical degradation potential of B. subtilis and other microorganisms and the compatibility existing between certain pesticides and the agricultural environment.