Encore un excellent exemple, des recherches qu’il convient de conduire encore pour trouver une solution naturelle au contrôle des CRP/RPW. Une occasion de plus de constater que les acteurs français du monde du palmier préferrent s’invectiver et s’enfermer dans des impasses ne se donnant absolument pas les moyens de leurs ambitions.
L’article appelle de ses vœux un vaste programme de dépistage des métabolites secondaires des plantes. Il nous informe sur le potentiel pesticide des sesquiterpènes (C15 H24), une classe importante de métabolites secondaires de plantes. Ces résultats réputés encourageants ont permis de proposer la picrotoxine comme biopesticide prometteur pour lutter contre les infestations de charançons rouges.
https://www.mdpi.com/1420-3049/24/9/1648
Abstract *
Natural biopesticide development for invasive populations of red palm weevils is mainly responsible for the destruction of date palms and demands an extensive screening program of plant secondary metabolites. In the current study, the pesticidal potential of sesquiterpenes (C15 H24), an important class of plant secondary metabolites primarily composed of three isoprene units, was evaluated by laboratory toxicity, feeding performance bioassays, and host detoxification gene expression patterns. Dose-mortality response bioassays performed against mid-aged eighth-instar red palm weevil larvae revealed dose-dependent mortality. Only three sesquiterpenes, including Farnesol (LD50 = 6559 ppm) and Farnesyl acetate (LD50 = 7867 ppm), are considered to have significant toxicity, with Picrotoxin (LD50 = 317 ppm) being the most toxic. Furthermore, highly toxic sesquiterpene (Picrotoxin) established in the current study tremendously reduced the feeding performance indices, including the efficacy of conversion of digested food (ECD) (81.74%) and the efficacy of conversion of ingested food (ECI) (73.62%). The least toxic sesquiterpenes, including β-Caryophyllene, (+)-Cedrol, Nerolidol, (+)-Nootkatone, and Parthenolide, observed in the current study failed to impart significant reductions of ECI and ECD indices. Lethality of the least toxic sesquiterpenes was overcome by greatly inducing gene expressions of Glutathione S transferase (GST) and Cytochrome P450. These encouraging results enabled us to suggest Picrotoxin as a promising biopesticide for the control of red palm weevil infestations.
* mécanique « autres langues » retour au français
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