TITLE:
Biomonitoring the Vitex gardneriana Shauer (Lamiaceae) Toxic Effects to Shed Light on Bioactive Compounds against a Major Coconut Pest Mite
AUTHORS:
Anderson Soares de Almeida, Caroline Rabelo Coelho, Mirele Santana de Sá, Edson de Souza Bento, Alberto Wisniewski Junior, Adenir Vieira Teodoro, Haroudo Sátiro Xavier, Jose Guedes de Sena Filho
KEYWORDS:
Bioassay, Toxicity, Phytochemistry, Terpene, Biopesticides, Biorational Control
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.12 No.11,
November
5,
2021
ABSTRACT: The coconut mite, Aceria guerreronis Keifer (Acari:
Eriophyidae), is a major pest of coconut plantations (Cocos nucifera L.) worldwide. Here,
we conducted a bioguided phytochemical
approach using toxicity and repellency bioassays of nonpolar extract and its
fractions of Vitex gardneriana Schauer (Lamiaceae) leaves to this pest. Nonpolar crude extract was
fractionated by column chromatography using solvents with increased polarity
and binary mixtures, resulting in five semipurified groups. The biomonitoring bioassay provided active
fractions and led to the isolation and characterization of the bioactive compound squalene, a biosynthetic
precursor of 20-hydroxyecdysone, which plays an important role in plant
defense against arthropods. The LC50 of the crude extract of V. gardneriana for A. guerreronis was estimated to
be 0.185 mg·mL-1 and LC80 = 4.123 mg·mL-1.
Also, the extract was highly repellent to this pest for up to 24 h. The
fractions of V. gardneriana,
and also squalene, caused mortality to A. guerreronis. The potential of V. gardneriana fractions/squalene
as biopesticides for controlling A. guerreronis in coconut plantations is discussed herein.