Fungitoxicidade de extratos vegetais sobre Pestalotiopsis psidii causador de podridão de frutos de goiaba (Psidium guajava L.)

Abstract

Guava is a fruit widely consumed throughout Brazil. However, problems that occur in fruit production are common, with postharvest rot being the most important as it causes damage to 45% of the fruit. The objective of this work is to evaluate the fungitoxic effect of plant extract in the control of Pestalotiopsis pisidii, the causal agent of Psidium guajava rot. The work was developed at the IFPI campus Cocal. The first stage of the experiment was the survey of the main fungi causing postharvest rot of guava fruits sold at the open market in Cocal, PI. Subsequently, in vitro tests were performed with aqueous plant extracts obtained from Hymenaea courbaril, Luehea divaricata and Copernicia prunifera at concentrations of 0 µL/mL, 1 µL/mL, 5 µL/mL, 15 µL/mL and 20 µL/mL in medium of PDA culture. The in vivo tests were carried out with treatments: EA24 = aqueous plant extract deposited 24 hours before P. psidii inoculation. ED24 = aqueous plant extract deposited 24 hours after inoculation of P. psidii and CONTROL = 1 mL deposition of ADE. Twenty fungi were isolated and P. psidii was 30% more frequent in the isolations. In the in vitro test, the best treatment was the Copernicia prunifera extract at doses of 5 and 20 µL/mL of PDA, reducing the mycelial growth of P. psidii by 64%. In the in vivo test, the EA24 treatment showed excellent results with 100% control of postharvest rot disease of guava fruits analyzed in the experiment