Bioactivity of Piper aduncum L. essential oil for insect pests of stored products¹

Bioatividade de óleo essencial de Piper aduncum L. para insetos-praga de produtos armazenados

ABSTRACT

Determining the bioactivity of essential oils extracted from plants is crucial for the development of alternatives for controlling insect pests in stored grains. This study aimed to investigate the bioactivity of Piper aduncum L. essential oil for the control of Sitophilus zeamais (Coleoptera: Curculionidae), Sitophilus oryzae (Coleoptera: Curculionidae) and Cryptolestes ferrugineus (Coleoptera: Cucujidae). Bioassays were conducted to determine the oil toxicity, sublethal effects, attractiveness and flight initiation behavior. Toxicity tests were carried out to determine the lethal concentrations for 50 and 95 % of the insects (LC₅₀ and LC₉₅). Tests were also performed with sublethal exposures to C. ferrurineus, S. oryzae and S. zeamais, using their respective LC₅ values (0.0002, 0.097 and 0.11 µL cm^-2), to investigate effects on the attraction or repellency activity, as well as flight tests. C. ferrugineus showed greater LC₅₀ (0.0005 µL cm^-2) and LC₉₅ (0.0012 µL cm^-2) susceptibility, in relation to S. oryzae LC₅₀ (0.35 µL cm^-2) and LC₉₅ (1.26 µL cm^-2), and S. zeamais LC₅₀ (0.39 µL cm^-2) and LC₉₅ (1.40 µL cm^-2). The exposure to the sublethal LC₅ concentration influenced the behavioral responses of attractiveness/repellency and flight activity. The oil had a neutral effect on C. ferrugineus LC₅ (0.0002 µL cm^-2) and an attractive effect on S. oryzae and S. zeamais LC₅ (0.097 and 0.11 µL cm^-2), and can be considered a potential insecticide for controlling pest weevil species of stored grains.

KEYWORDS:
Piperaceae; potential insecticide; stored-grain pests