Adulticidal activity of essential oils of Mentha piperita L., Cupressus sempervirens L., and Eucalyptus globulus Labill. against the tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae)

Abstract

The tomato miner Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is a Neotropical species, which cause serious damages to tomato both in open fields and under greenhouses. Chemical control using synthetic insecticides was the primary method of control of this pest, but it has showed negative implications due to high costs, and risks for human health and environment. Therefore safer alternatives are required to control of tomato leafminer as the use of natural insecticides. In this work we investigated the insecticidal activity of essential oils (EOs) of peppermint, Mentha piperita L., cypress, Cupressus sempervirens L., and eucalyptus, Eucalyptus globulus Labill., used for the first time against adults of T. absoluta. After 1 and 24 hours of exposure to EOs, the mortality rates at different concentrations were obtained. Mortality responses was variable depending on EO concentrations and time of exposure to treatments. It is remarkable that already after 1 hour of exposure all three EOs caused mortality with maximum values of 60% for peppermint (at dose of 50 μl/ml), 70% for cypress (at dose of 12 μl/ml) and 100% for eucalyptus (at dose of 7 μl/ml). At 24 hours the greatest activity, with values of 100% mortality, was detected for eucalyptus EO (at dose of 3 μl/ml) followed by cypress EO (at dose 7 μl/ml) and lastly peppermint EO (at dose 10 μl/ml). Results of the probit analysis after 24 hours revealed that adults were more sensitive to cypress EO than eucalyptus EO and peppermint EO, with corresponding LD50 values of 1.31 μl/ml, 1.45 μl/ml, and 3.98 μl/ml, respectively. These results suggest that E. globulus, C. sempevirens and M. piperita EOs have effective insecticidal activity on adults of T. absoluta.