TITLE:
Potential Use of Essentials Oils to Control Fruitlet Core Rot (FCR) in Pineapple (Queen Victoria Variety) in Reunion Island
AUTHORS:
Marc Chillet, Angélique Hoareau, Mathilde Hoarau, Jérome Minier
KEYWORDS:
Essential Oils, Fruitlet Core Rot, Pineapple, Postharvest Treatment, Thymol
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.11,
November
13,
2020
ABSTRACT: Fruitlet Core Rot (FCR) is one of the major postharvest
diseases of pineapple (Ananas comosus var. comosus), especially
on the prone variety Queen Victoria cultivated in Reunion Island. This
aggressive disease is generally due to two pathogens: Fusarium ananatum and Thalaromyces
stolii, and needs to be controlled during postharvest. In Reunion Island, F. ananatum is the principal causal
agent impacting fruit exportation. Fruit produced for the export market is
generally treated with chemicals. This type of postharvest treatment is not in
line with consumer expectations, as consumers prefer fruits treated with
nonharmful and natural products. The objective of this work was to study
alternative postharvest treatments using the fungitoxic properties of essential
oils and their ability to elicit the resistance mechanisms of the fruit. Six
EAs were tested in vitro on mycelial
growth of F. ananatum. Whether by
volatilization or included in the culture medium, some essential oils such as
thymol, eugenol, geraniol and the carvone/menthol mixture have a strong
fungistatic effect. But only thymol has a fungitoxic effect. The thymol, a
natural molecule synthesized by thyme (Thymus vulgaris L. thymoliferum) is the more effective in vitro and is the strongest potential
to be used in postharvest treatment. Thymol, prepared at 0.025% in a terpene
solvent that acts as a penetrating agent, was tested in vivo with inoculated fruits. The treatment was effective only on
necrosis development from the upper part of the fruits. Pineapple polyphenol
biosynthesis appears to have been suppressed by thymol treatment. Results and
opportunities for this treatment are discussed. Additional experiments must be
carried out in order to decide on the advisability of this type of treatment.