مشخصات پژوهش

Pesticide application is one of the effective control methods of pests. However, their diverse effects on human health, beneficial and environment have provoked experts to seek alternative measures. Botanical pesticides with relative safety to environment and non-target organisms could be used in pest management programs. In this study, combination effects of hexane extracts of Falcaria vulgaris and Apium graveolens with microbial pesticide Bt var Krustaki were investigated on life span and adult emergence rate of potato tuber moth (PTM), Phthorimea operculella. Extraction was carried out by standard maceration method using hexane as non-polar solvent. PTM larvae were reared on potato tubers in controlled condition. First larval instar of PTM were introduced on same shape and size potato tubers treated with LC50 and LC30 values of both plant extracts and Bt. For co-toxicity evaluation, combination of Bt and plant extracts were tested in above mentioned concentrations. Treated tubers were kept in growth chamber at 25 ± 2 ºC, 50 ± 5 % RH and 16:8 (L:D) h. Larval developmental time, number of pre-pupa, pupae and adult individuals were recorded in control and treatments daily. Results revealed that larval life span of insects increased in treatments with a dose dependent manner. LC50 values of plants extracts and Bt increased larval duration by 8 ± 0.52 and 5 ± 0.45 days in comparison with control, respectively. However, LC50 values of Bt combined with the same value of both plants extracts significantly increased the larval developmental time by 45 ± 5.4 days compared with that in control. LC50 values of Bt, F. vulgaris and A. graveolens decreased adults emergence by 47.66, 45.52 and 53.33 %, respectively. Moreover, adults emergence decreased by 66.6 and 70.5 % when they were treated by combined doses of LC50 of Bt and LC30 of F. vulgaris and A. graveolens, respectively. No adult emergence was recorded after 60 days when they were exposed to combination treatment of Bt