February 2015
Date:
28 Feb 2015
Alternative control of Chalara paradoxa, causal agent of black rot of pineapple by plant extract of Mormodica charantia
- Wilza Carla Oliveira de Souza,
- Luciana Cordeiro do Nascimento,
- Daniele Lavra Vieira,
- Taciana Silva dos Santos,
- Francisco Miguel de Assis Filho
Abstract
Black rot of pineapple caused by the fungus Chalara paradoxa
is considered an aggressive and difficult disease to control. The use
of natural products has been studied with the goal to incorporate them
into integrated pest management and reduce the use of agrochemicals.
Plant extracts have shown satisfactory results in controlling
postharvest diseases by providing fungitoxic action and inducing plant
resistance. The aim of this study was to evaluate C. paradoxa severity by the application of plant extract of Mormodica charantia,
determinate effect of the plant extract on post-harvest quality, and
induction of enzymes linked to host resistance induction. The following
treatments were studied: plant extract of bitter melon at concentrations
of 10, 100, 500 and 1000 ppm, the commercial products
acibenzolar-S–Methyl and fungicide (thiabendazole) in the dosages
recommended by the manufacturers, and distilled water as the control,
with five replications and two plants per plot. The extract of M. charantia reduced the severity of black rot caused by C. paradoxa,
compared to the control treatment, showing similar efficacy to the
treatments with commercial inductor Acibenzolar-S-methyl and the
fungicide. The enzymatic analysis showed increase of the peroxidase by
the use of the bitter melon extract along the evaluation period. The
enzymes polyphenol oxidase and phenylalanine ammonia lyase showed
greater activity by treatment with M. charantia
extract at 500 ppm. It was observed that the plant extract did not
affect most of the variables analyzed related to postharvest quality of
treated fruits. The use of the extract reduced the fruit weight loss,
being a positive aspect under the studied conditions.
