Chemical composition and insecticidal effects of the essential oil of cardamom, Elettaria cardamomum on the tomato leaf miner, Tuta absoluta.
Tuta absoluta is one of the key pests of Solanaceae family in the world. This insect is an oligophagous pest and its larva causes damage on the host plants by feeding on leaf, stem and fruit of them. In the current study, chemical composition and insecticidal activities of the essential oil from cardamom, Elettaria cardamomum on egg, the 2nd larval instars and adults of T. absoluta were evaluated. Results indicated that oil is toxic to the T. absoluta. The major components in the oil were as follow: terpinenyl acetate (36.61%), 1,8-cineole (30.42%), linalyl acetate (5.79%) and sabinene (4.85%). LC50 values for eggs, larvae and adults were 351.19, 7.88, 1.55 and 1.88 µl L-1 air, respectively. The tomato leaf miner (TLM), T. absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a important pest on tomato, potato and other Solanaceous with a huge economic importance. TLM can be regarded as a serious threat to tomato production in Iran. TLM larvae cause about 100% losses by attacking tomato leaves, flowers, stems and especially fruits. The discovery of active compounds that are less persistent will be beneficial to both the environment and agricultural product consumers. Management of the pest can be problematic, especially when the infestation pressure is high. The utilization of natural compounds such as plant essential oils is considered as a alternatives to chemical pesticides because of their lower toxicity on the non-target and low persistence in the environment. In the present study, the chemical composition and insecticidal activities of the essential oil from cardamom, E. cardamomum (Maton) (Zingiberales: Zingiberaceae) on egg, the 2nd larval instars and adults of T. absoluta were evaluated. The essential oil was obtained by hydrodistillation method, using a modified clevenger-type apparatus. Experiments were performed at 27±2°C, 65±5% RH and 16 L:8D h photoperiods. Results showed that the essential oil of E. cardamomum is toxic to T. absoluta. The major components in the oil were α-terpinyl acetate (36.61%), 1,8-cineole (30.42%), linalyl acetate (5.79%) and sabinene (4.85%). Probit analysis showed that the LC50 values for eggs, 2nd larval instar (inside leaf, outside leaf) and adults were 351.19, 7.88, 1.55 and 1.88 µl L-1 air, respectively. The overall results showed that cardamom essential oil has high potential in controlling TLM, especially in protected areas.