PRODUCTION OF GRAVIOLA SEEDLINGS IN DIFFERENT COMBINATIONS OF SUBSTRATES AND CONTAINERS

Abstract

Brown rot, caused by the fungus Monilinia fructicola, is the most important peach tree disease, as it causes losses from flowering to post-harvest. Given the indiscriminate use of fungicides, more sustainable alternatives for disease control have been sought. Thus, the study aimed to verify, in vitro, the fungistatic effect of aqueous plant extracts of rosemary, garlic and horsetail on the fungus. Three aqueous plant extracts (garlic, rosemary and horsetail) were evaluated at five concentrations, namely: 0 (control), 5, 10, 15 and 20% (g mL-1). The treatments were applied in a completely randomized design (CRD), with 4 replicates in a 3x5 bifactorial arrangement. The first factor was the plant extracts and the second factor was the concentrations, each experimental unit being a Petri dish. The data were subjected to analysis of variance. The differences between the means were compared in Scott Knott at 5% probability of error and the concentrations, by polynomial regression. Afterwards, the extracts were added to the liquid PDA medium and subsequently allowed to solidify. After inoculation, all plates were sealed and incubated in BOD at 25 °C for 10 days. Mycelial growth, growth rate, percentage of growth inhibition and mycelial growth velocity index were evaluated. There was a significant interaction between concentrations and plant extracts. Horsetail and rosemary resulted in growth inhibition of 67.91% and 53.47% and growth rate of 42.37% and 49.37% for concentrations of 15 and 20%, respectively. Rosemary and horsetail resulted in mycelial growth of 22.46 cm and 16.88 cm, when compared to garlic, resulting in mycelial growth velocity index of 0.42% and 0.29%, respectively. The best controls were with garlic extract, at concentrations of 5, 10, 15 and 20%. It can be concluded that garlic extract has fungistatic and fungitoxic action on the fungus in vitro.