Acaricidal potential of Bidens pilosa in the control of the red palm mite

Raoiella indica Hirst, 1924 (Prostigmata: Tenuipalpidae), is one of the leading pest mites on plants of the Arecaceae family, especially palm and banana trees. This species has a high reproductive capacity and rapid dissemination, but the control methods available for this species are still limited. Therefore, this work aimed to evaluate the acaricidal effect of blackjack (Bidens pilosa) on adult individuals of R. indica. The experiment was conducted in a completely randomized design, using the plant structures of blackjack to prepare the extracts. The experimental units consisted of coconut leaf discs (4 cm), with moistened cotton at the bottom of the Petri dish (10.0 × 1.2 cm), and around the disc to maintain turgidity and prevent mites from escaping. Spraying was carried out on 12 adult females of R. indica per sample unit, with seven repetitions for each concentration, using an airbrush with a constant pressure of 1.3 psi and 1 mL of solution per repetition plate. The acaricidal effect was evaluated 12, 24, 36, 48, 60, and 72 hours after spraying. The mortality of R. indica was proportional to the increase in the concentration of the blackjack plant extract, and the lethal concentrations obtained, CL50 and CL 90, were estimated between 1.49% and 4.19%, indicating the acaricidal potential of B. pilosa. Phenolic compounds were the majority of compounds found in this study.