EVALUATION OF FUMIGANT TOXICITY OF MENTHA PULEGIUM ESSENTIAL OIL AGAINST TETRANYCHUS CINNABARINUS UNDER GREENHOUSE CONDITIONS

摘要

The carmine spider mite, Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae), is one of the most economically important pests of greenhouse-grown vegetables and ornamentals in southwestern part of Turkey (Antalya). In the present study, the fumigant toxicity of Mentha pulegium L. (Lamiaceae) essential oil was tested against T. cinnabarinus on cucumber under greenhouse conditions in the autumn of 2007. Two successive applications with the oil using a concentration of 4 μL/L air were made at a time when the majority of mites were at active stages (larva, nymph and adult) of development. The first application in mid-October was applied in mid-day at a temperature of ～ 45℃ (inner temperature at the greenhouse). The second application in mid-November was made in the evening (at 12℃) in the same greenhouse. After an exposure period of 12 h, treatment efficacy was determined by counting live/dead individuals (larva, nymphs and adults) from leaf samples, compared with that of a non-treated control. Sampling was done 1 day before and 1, 3, 7 and 14 days after treatments. Fourteen days after each application, the first one resulted in 89.25% and 72.93% reduction in the populations of larva + nymphs and adults of the pest, respectively, compared to the non-treated control, whereas the second one in the evening was less effective (54.13% and 50.85%, respectively). Pulegone, determined by gas chromatography-mass spectrometry, was the major constituent of the oil (94.99%). The results obtained suggest that the essential oil from M. pulegium has potential to be used as a fumigant for management of T. cinnabarinus under greenhouse conditions.