بررسی اثرات تخم‌کشی و دورکنندگی عصاره گیاهان علف داسی و کرفس بر بید سیب‌زمینی

The potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechidae), is a cosmopolitan pest of potato, Solanum tuberosum L. (Solanales: Solanaceae), and is considered the most damaging potato pest in tropical and subtropical agroecosystems. PTM larvae cause some damage by feeding on leaves, stems, and petioles in the field but cause the most significant damage by tunneling in the potato tubers in the field and particularly during storage. By conducting several laboratory experiments the ovicidal and repellent effects of Hexane, Ethyl acetate and methanol extracts of Falcaria vulgaris Bernth (Apiaceae) and Apium graveolens L. (Apiaceae) were evaluated against Potato Tuber Moth (PTM), Phthorimaea operculella (Zeller) (Lep.: Gelechiidae). Hatch rate was evaluated by dipping one day old eggs in different concentrations of plants extracts for 5 second. Then the eggs were air dried for 20 minutes and transferred to experimental tubes. Repellent effect was tested using equal size of impregnated potato slices (5 cm in diameters) with 0.625, 2.5 and 10 gr/l (gram per liter) concentrations of extracts as treatments across 4 replications. Whole experiments were run twice at 25±2°C, 50±5% RH and 16:8 LD conditions. Five couples of 2days old (mated) PTM were incubated in experimental area containing four slices of potato (including control and treatments) and percentage of eggs were recorded in each treatment after 24 hours. The experiments designed as choice tests. The ovicidal LC50 values of Hexane extracts of F. vulgaris and A. graveolens were 2.5 and 2.12 gr/l, respectively. Ethyl acetate based extract of A. graveolens was the most effective ovicid with LC50 values of 1.4 gr/l. The methanolic extract of both plants showed no ovicidal activity. At treatments of hexane extracts of F. vulgaris and A. graveolens percentages of oviposition were 43 and 31, respectively. These values were 20 and 0 for Ethyl acetate and 30 and 46 percent in the case of Methanol extracts. Overall for all extracts, oviposition reduced significantly at two concentrations including 10 and 2.5 gr/l. The results showed that ovicidal and repellent effects of extrats are concentration-dependent and Ethyl acetate based extracts of both plants have promising ovicidal and repellent effects against PTM.