Action of Schinus terebinthifolius Raddi essential oil on the in vitro growth of Colletotrichum truncatum, the causal agent of anthracnose in soybean plants

Abstract

Soybean is a crop of great economic importance worldwide and has been widely cultivated by family farmers, mainly in the southern region of Brazil. Crop productivity is frequently compromised by several pathogens, including the fungus Colletotrichum truncatum, the causal agent of anthracnose. Conventional control of this disease is predominantly carried out through synthetic fungicides, which has raised concerns related to environmental insecurity and human health. In this sense, the use of vegetable oils as an ecological method of phytopathogenic control becomes an interesting alternative to the use of synthetic chemicals. Thus, the objective of this study was to evaluate the effect of essential oil of Schinus terebinthifolius Raddi on the in vitro growth of Colletotrichum truncatum. The experiment was conducted with four treatments, performed in petri dishes containing potato dextrose agar (PDA) culture medium, with T1 being the control without oil application, T2 with oil added to the PDA medium before solidification, T3 with oil applied to the surface of the already solidified medium, and T4 with oil applied to filter paper placed on the plate lid, and all treatments at concentrations ranging from 25 to 800 μL/20 mL. The use of pink pepper essential oil was efficient in inhibiting the mycelial growth of C. truncatum, in all tested methods (treatments), but the greatest inhibition occurred in T3 at a concentration of 800 μL/20 mL. The result of this study suggests that pink pepper essential oil may be a promising natural alternative to agrochemicals currently used to combat soybean anthracnose and should be further trained in in vitro and especially in vivo tests to better understand the dynamics/biochemistry of the processes involved.