Extrato etanólico de própolis no controle alternativo da pinta preta (Alternaria solani) e septoriose (Septoria lycopersici) na cultura do tomateiro

Abstract

The tomato represents one of the main cultivated vegetables, but its production is limited by the occurrence of phytosanitary problems by the diseases that affect the production. The objective of this work was to contribute to the alternative control of diseases of black and septoriose, Alternaria solani and Septoria lycopersici of the tomato with the use of propolis ethanolic extract (EEP). Mycelial growth and spore germination bioassays were performed to evaluate the direct antifungal activity of the propolis ethanolic extract on A. solani and S. lycopersici. The bioassays were the ethanolic extract of propolis at concentrations of 0.5; 1.0; 1.5; 2.0 and 3.0% and as control with distilled water. For mycelial growth the treatments were incorporated in autoclaved and non-autoclaved BDA medium. The evaluations were performed through the daily measurements of the diameter of the colonies after five days of the installation of the experiment. Germination of spores and germination size of A. solani and S. lycopersici were also evaluated. Under greenhouse condition experiments were conducted to assess the severity of the diseases and biochemical analyzes. The treatments were sprayed on tomato plants 45 days after sowing and 72 hours after inoculation of the fungi. In another experiment, the tomato plants were sprayed and there was no inoculation with fungi. Samples were collected for analysis of defense-related enzymes. The experiments were conducted in a completely randomized experimental design (DIC) with four replicates. EEP showed antifungal activity inhibiting mycelial growth and spore germination of both phytopathogens with 100% inhibition at the highest concentration. There was a tendency in the increase of the activity of the enzymes. With the exception of polyphenoloxidase in tomato leaves treated with different concentrations of EEP. According to the quadratic equation the maximum activity point of the enzyme was 2.0%. At the 3% concentration, there was a decrease in the enzymatic activity. These results indicate the potential of the EEP in the protection of tomato plants to A. solani and S. lycopersici.