Zinc-dithiocarbimates for the control of Hemileia vastatrix: a versatile alternative

The purpose of this work was to investigate the potential use of zinc-dithiocarbimate salts to control Hemileia vastatrix, the causal agent of the coffee leaf rust disease, and to evaluate their toxicity towards Apis mellifera, one of the most important coffee plant pollinators.

Zinc-dithiocarbimate salts were prepared and fully characterized by infrared, proton (¹ H) and carbon-13 (¹³ C) nuclear magnetic resonance and elemental analyses of carbon (C), hydrogen (H), nitrogen (N) and zinc (Zn). X-ray diffraction technique studies confirmed the proposed structures. The salts inhibited the germination of H. vastatrix spores in vitro, with a 50% inhibitory concentration (IC₅₀ ) from 12 to 18 μmol.L^-1 and a 90% inhibitory concentration (IC₉₀ ) from 23 to 26 μmol.L^-1 . Zinc-dithiocarbimate salts with the best in vitro results were selected for in vivo experiments with Coffea arabica var Caturra and with the pollinator A. mellifera. The results were similar to those of Mancozeb, a broad-spectrum contact fungicide, with a good control of the disease and low toxicity to the honeybee.

The zinc-dithiocarbimate complex salts have potential to control coffee leaf rust, with low toxicity to the pollinator insect. © 2022 Society of Chemical Industry.