Dose-response and chemical characterization of an aqueous extract of Bidens pilosa against Oligonychus ilicis (Acari: Tetranychidae)¹

Dose-resposta e caracterização química de extrato aquoso de Bidens pilosa sobre Oligonychus ilicis (Acari: Tetranychidae)

The Oligonychus ilicis (McGregor) (Acari: Tetranychidae) mite is an important pest of Conilon coffee (Coffea canephora). Botanical extracts may offer a promising sustainable alternative for its management. This study aimed to evaluate the dose-response of an aqueous extract of Bidens pilosa against adult females and eggs of O. ilicis, as well as to quantify its total phenolic, tannin, and flavonoid contents. B. pilosa plants were used to prepare aqueous extracts at concentrations of 0.40, 0.65, 1.05, 1.71, 2.77, and 4.50 % (w/v), with Tween^® 80 (0.05 % v/v) as an adjuvant. Both adult female mortality and egg unviability increased with extract concentration. The estimated LC₅₀ values were 0.92 % (w/v) for adult females and 1.21 % (w/v) for eggs. Chemical analyses quantified total phenolic, tannin, and flavonoid contents of 47.747 µg GAE mg^-1 of extract, 25.774 µg GAE mg^-1 of extract, and 33.535 µg QE mg^-1 of extract, respectively.

KEYWORDS:
Coffea canephora ; blackjack; coffee red mite