Control of Coffee Leaf Rust by Chitosan Oligomers and Propolis

Abstract Broad scale use of chemical pesticides is known to have produced broad scale environmental impact worldwide and, at the same time, discovery and registration of new molecules to be used as insecticides, herbicides and fungicides have slowed significantly along the last decades, reducing the number of options for pest control by the farmers. Searches for novel environmentally friendly products are a recognized priority. In this work, aqueous solutions of chitosan oligomers (COs) and propolis (P), individually or as binary mixtures, were tested against Hemileia vastatrix, the fungus which causes coffee leaf rust, the worst disease of coffee. Germination of H. vastatrix was inhibited up toll 99 % by COs, followed by the mixture of COs-P and P individually (germination inhibition of 96 % and 54 % respectively). Testing those products on detached coffee leaf discs also produced promising results when COs were applied before H. vastatrix inoculation. These results may lead to the discovery of new antifungal products for the control of coffee leaf rust.