Lethal effects of peppermint, eucalyptus, and rosemary essential oils as nano-capsule and emulsion formulations on tomato leaf-miner (Tuta absoluta)

Following commercial use of plant essential oils in pest control, their slow-release formulations have been developed in order to increase their effectiveness and solve their instability problem. In the present study, at first, lethal effects of peppermint (Mentha piperita L.) and rosemary (Rosmarinus officinalis L.) essential oils as emulsions and nano-capsules on the tomato leaf-miner was determined by the leaf-dipping method. Mortality of different concentrations (1, 5, 10, 20, and 40 percent) recorded at 24, 48, and 72 h after treatment. Then, negative effects of these essential oils on life table parameters were evaluated at 10% concentration. The results of the toxic effects of these essential oils at the selected concentration showed a significant increase in the larval duration in both treatments compared to that of control. The longest larval duration was observed in nano-capsule formulation of rosemary (9.24 ± 0.15 day) and the lowest larval duration was observed in the control (7.78 ± 0.16 day). However, the nano-capsule formulations of essential oils had no effect on the adult longevity, but peppermint nano-capsule significantly decreased the ovipositional period compared to that of control and rosemary nano-capsule. Fertility and survival rates were also significantly decreased in females treated with rosemary nano-capsule. In general, rosemary essential oil has the ability to use in integrated pest management programs because of a reasonable reduction in the pest developmental parameters, higher inhibition effect on adult female oviposition, and lower damages to plants.