ATIVIDADE NEMATICIDA DO ÓLEO ESSENCIAL DA POLPA DE PEQUI (Caryocar brasiliense) NO CONTROLE DE Meloidogyne javanica

Abstract

Phytonematode are parasites that seriously affect plants worldwide, reducing agricultural productivity, especially those belonging to the genus Meloidogyne. The search for new alternative strategies for the management of phytonmatoids to replace conventional synthetic nematicides is a concern of nematologists worldwide. The native plants of the cerrado have great potential to be used in the alternative management of phytonematodes. The use of extracts and vegetable oils is used in studies of their biological activities with positive results in the control of insects and microorganisms that cause plant diseases. Pequi, Cariocar Brasiliense, was the species chosen for being a native and very popular plant in the cerrado, in addition to having some proven medicinal importance. The present study aimed to verify the efficiency of the pequi pulp essential oil in the control of Meloidogyne javanica nematode. The experiment was carried out between the months of November and December 2019 in laboratory conditions. 500 g of pulp from the internal mesocarp of the pequi and 2000 mL of water were used. The pequi essential oil (OEP) was extracted from the aqueous phase using hydrodistillation. After this process, the OEP was stored in a B.O.D incubator at 25 ºC without changing the temperature until the moment of analysis. 80 juveniles of second stage (J2) were incubated in the following treatments: 1) control (2 mL of distilled water), 2) 2, 4, 8 and 16 mg L-1 of pequi essential oil. J2 were obtained from the egg suspension maintained at a temperature of 25 ºC ± 1ºC for 3 days. Then, the number of J2 was counted with the aid of a Peters camera, under a photonic microscope, at 40x magnification. It used a completely randomized experimental design, composed of five treatments and five repetitions, totaling 25 experimental units. The results obtained in the experiment were significant, noting that the mortality percentage of the J2 in the T5 treatment (16 mg L-1) was 82% and T3 (4 mg L-1) 66%, indicating the efficiency of using essential oil pequi in the control of Meloidogyne javanica. All the fractions of the pequi essential oil (, 2, 4, 8, and 16 mg L-1), analyzed had a positive effect on the control of J2 of Meloidogyne javanica, but the highest concentration (16 mg L-1) was better highlighted. which led to the mortality of 82% of juveniles.