Bioactivity of compounds from Acmella oleracea against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and selectivity to two non‐target species

• Published in: Pest management science 2012-03, Vol.68 (3), p.386-393
• Main Authors: Moreno, Shaiene C, Carvalho, Geraldo A, Picanço, Marcelo C, Morais, Elisangela GF, Pereira, Rogério M
• Format: Article
• Language: English
• Subjects: aerial parts; Agronomy. Soil science and plant productions; Animals; Ants - drug effects; Asteraceae - chemistry; Bees - drug effects; bioactive alkamides; bioassays; Biological and medical sciences; botanical pesticide; Chemical compounds; Control; crops; ethanol; Fundamental and applied biological sciences. Psychology; hexane; insect control; insecticidal properties; insecticides; Insecticides - pharmacology; lethal dose 50; Lycopersicon esculentum - parasitology; Moths - drug effects; Pest control; Pesticides; pests; Phytopathology. Animal pests. Plant and forest protection; Plant Diseases - parasitology; Plant Extracts - pharmacology; Plant reproduction; Protozoa. Invertebrates; screening; secondary metabolites; Solenopsis saevissima; Species Specificity; Tetragonisca angustula; tomato leafminer; Tomatoes; Tuta absoluta
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.2274

BACKGROUND: Tropical plants are recognised sources of bioactive compounds that can be used for pest control. The objective of this study was to evaluate the biological activity of compounds present in Acmella oleracea (Asteracea) against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), which is the main pest of tomato crops in Latin America. The selectivity of these compounds to the predator Solenopsis saevissima (Smith) (Hymenoptera: Formicidae) and to the pollinator Tetragonisca angustula (Latr.) (Hymenoptera: Apidae: Meliponinae) was also of interest. RESULTS: A bioassay screening with hexane and ethanol extracts from 23 plants was performed. The hexane extract of A. oleraceae was the most active of the extracts and was selected for further study. The following three alkamides were isolated from a hexane extract of the aerial parts of A. oleracea: spilanthol, (E)‐N‐isobutylundeca‐2‐en‐8,10‐diynamide and (R, E)‐N‐(2‐methylbutyl)undeca‐2‐en‐8,10‐diynamide. All of the isolated compounds showed insecticidal activity, with spilanthol being the most active (LD50 = 0.13 µg mg−1) against T. absoluta. The alkamides were selective to both beneficial species studied. CONCLUSION: The crude hexane extract of A. oleraceae showed high insecticidal activity and can be used to control T. absoluta in organic or conventional crops. Quantification of LD50 values of isolated compounds against T. absoluta showed that alkamides could serve as potent insecticides for T. absoluta control programmes. Spilanthol was the main alkamide active isolated. This alkamide is the most promising as it has the highest insecticidal activity and is selective to non‐target organisms.