Lethal Effects and Oviposition Deterrency of Celery, Apium graveolens, and Sickleweed, Falcaria vulgaris, Against the Potato Tuber Moth, Phthorimaea operculella in laboratory conditions

Extracts of some plants could be used as botanical pesticides because of their lethal effects, repellency and antifeedant activity on insect pests. In this study, bioactivities of different extracts of two plant species, the sickleweed Falcaria vulgaris Bernhand the celery Apium graveolens L., (both belonging to the Apiaceae family) were evaluated against the potato tuber moth (PTM) Phthorimaea operculella (Zeller, 1873). Insects were reared in controlled conditions at 26±2ºC, a photoperiod of 16:8 (L: D) h and 50±5% RH, on potato tubers. Foliage of plants were washed by distilled water, and air-dried in shadow. Extraction was carried out by maceration method using hexane, ethyl acetate and methanol as solvents of different polarity, respectively. Ovicidal activity, lethal toxicity against 1st instars and oviposition deterrency of extracts were investigated. The median lethal concentration (LC50) of hexane and ethyl acetate extracts of F. vulgaris against one-day old eggs of PTM was estimated as 2.5 and 3.38 g/l, respectively. Also, the same extracts of A. graveolens showed ovicidal activity at concentration rates of 2.12 and 2.81 g/l, respectively. Inhalation toxicity of hexane and ethyl acetate extracts of F. vulgaris with LC50 estimated values of 5.59 and 13.43 mg/l was significantly more than other extracts. Methanol extracts of both plants showed neither ovicidal nor inhalation toxicity. Ethyl acetate, hexane and methanol extracts of both plants showed effective oviposition deterrency against adults of PTM. Ethyl acetate extract of A. graveolens and F. vulgaris showed 100% and more than 80% oviposition deterrency respectively. Considerable toxicity and oviposition deterrency of both plant extracts detected in this study show their potential as a control agent in PTM management programs.