Contact and fumigant toxicity of Foeniculum vulgare and Citrus limon essential oils against Tetranychus turkestani and its predator Orius albidipennis

Abstract

Tetranychus turkestani is one of the most important pests of greenhouse plants in the southern provinces of Iran. Several benefits of using essential oils over chemical pesticides make them appropriate for IPM programs. Contact and fumigant toxicity of the essential oils of Foeniculum vulgare and Citrus limon against the spider mite and its predator, Orius albidipennis were investigated under laboratory conditions. Contact toxicity experiments were conducted at six concentrations, (0, 50, 100, 300, 800 and 2000 ppm) of each essential oil on the mature and immature life stages of the pest, and mortalities were recorded 72 h after exposure. In fumigant toxicity trials, LC 50 values of the essential oils were determined on different developmental stages of T. turkestani and O. albidipennis. At 800 and 2000 ppm, both essential oils had high contact toxicity on the eggs, 2 nd instar nymphs and adults of T. turkestani, while the same concentrations caused less mortality on O. albidipennis. No significant phytotoxicity of the essential oils was observed. The mortality rates of T. turkestani and O. albidipennis increased as concentration was increased. Also, the 2 nd instar nymph of T. turkestani was more sensitive to contact application of the essential oils than other developmental stages. In the fumigant toxicity bioassay, LC 50 values of the essential oil derived from F. vulgare on the egg, 2 nd instar nymph and adult of T. turkestani were 16.08, 7.98 and 14.06, and the values for C. limon essential oil were 11.6, 9.86 and 11.52 µl × l-1 air, respectively. The highest fumigant toxicity was observed against the 2 nd instar nymphs of the mite. Fumigant toxicity of the essential oils was lower against O. albidipennis than against T. turkestani. This data suggests that the essential oils of these plants have the potential of being employed in the IPM programs of T. turkestani in greenhouse crops, especially cucumber.

Evaluation of the Toxicity of Satureja intermedia C. A. Mey Essential Oil to Storage and Greenhouse Insect Pests and a Predator Ladybird

“…The essential oil of S. intermedia was more toxic on A. nerii (LC 50 : 418 µg/mL) than the predator ladybird C. septempunctata (LC 50 : 914 µg/mL), suggesting that the predator was more tolerant than the aphid to S. intermedia essential oil, which is very valuable in terms of predator protection. Similar results were obtained for controlling aphids [ 54 , 55 ] and some other insect pests [ 56 , 57 , 58 ] using plant-derived essential oils along with protecting their predators. However, the destructive side-effects of some essential oils on parasitoids have been reported [ 59 , 60 , 61 ].…”