J. Crop Prot. 2013, 2 (1): 23-31 ________________________________________________________ Insecticidal and repellent activities of Artemisia khorassanica, Rosmarinus officinalis and Mentha longifolia essential oils on Tribolium confusum Mahdieh Saeidi and Saeid Moharramipour* Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box 14115-336, Tehran, Iran. Abstract: The essential oils of aerial parts of three medicinal plants Artemisia khorassanica Podl., Rosmarinus officinalis L. and Mentha longifolia L. were isolated by hydrodistillation and investigated for their toxicity and repellency against Tribolium confusum Jacquelin du Val. at 27 ± 1 ºC and 60 ± 5% RH in darkness. The mortality of the adults increased with concentration from 185 to 1111 μl/l air and with exposure time from 9 to 24 h. A concentration of 185 μl/l air and exposure time of 24 h was sufficient to obtain nearly 100% kill of the adults in all of the three essential oils tested. At the highest concentration (1111 μl/l air) R. officinalis oil caused 15% mortality for an exposure time of 6-h. whilst, the oil of A. khorassanica resulted in 1% mortality at the same exposure time. The oil of A. khorassanica at 1111 μl/l air caused 81% mortality for 12-h exposure time. No significant differences were observed between the lethal time (LT50) values at essential oil concentrations of 741 and 1111 μl/l air. For 24-h exposure time, the LC50 values of A. khorassanica, R. officinalis and M. longifolia essential oils were estimated to be 22.45, 22.14 and 39.96 μl/l air respectively. Based on LC50 values, adults of T. confusum showed similar susceptibility to the A. khorassanica and R. officinalis oils, but M. longifolia oil proved to be less toxic. In contrast to their low fumigant properties, the essential oil of M. longifolia had significantly higher repellency to T. confusum adults than did the other two. Downloaded from jcp.modares.ac.ir at 19:01 IRST on Friday September 24th 2021 Keywords: Fumigant toxicity; Repellent; Artemisia khorassanica; Rosmarinus officinalis; Mentha longifolia; Tribolium confusum; essential oil Introduction12 of its ozone depletion potential. Additionally, some stored-product insects are found to have Control of insect pest infestation in storage may developed resistance to methyl bromide and cause special problems on stored products. In phosphine (Subramanyam and Hagstrum, 1995; many storage systems, methyl bromide and Champ and Dyte, 1977). These problems due to phosphine are the most economical fumigants conventional insecticides have strongly for management of stored-grain insect pests. demonstrated the need for the development of EPA (2001) has proposed elimination of the alternative products such as natural extracts production of methyl bromide by 2005 because derived from plants. Many types of spices and herbs are known to possess insecticidal activities (Tripathi et al., 1999) especially in the form of Handling Editor: Dr. Khalil Talebi Jahromi essential oils (Shaaya et al., 1991). They do not ________________________________ leave residues harmful to the environment and * Corresponding author, e-mail: [email protected] Received: 19 June 2012; Accepted: 13 January 2013 have lower toxicity to mammals (Duke, 1985). Among the medicinal plants, Artemisia vulgaris 23 Insecticidal and repellent activities of plant essential oils ________________________________ J. Crop Prot. L., Artemisia aucheri Boiss., Artemisia scoparia for 4 h using a modified Clevenger-type Waldst et Kit and Artemisia sieberi Besser have apparatus. The essential oils were dried over been reported to be repellent and toxic to anhydrous sodium sulfate and were stored in Tribolium castaneum (Herbst) (Wang et al., glass tubes at – 4 ºC in refrigerator, until they 2006; Shakarami et al., 2003; Negahban et al., were used. The oils yielded by A. khorassanica, 2006, 2007). The essential oil of R. officinalis R. officinalis and M. longifolia were 0.322, (Rosemary) showed insecticidal activity against 0.565 and 0.533% w/w respectively on dry Sitophilus oryzae L. and T. castaneum (Shaaya et weight basis. al., 1997; Lee et al., 2002). Some studies have assessed the fumigant toxicity of Mentha Insect rearing piperita L. and Mentha arvensis L. against T. Tribolium confusum was reared on wheat flour castaneum (Aggarwal et al., 2001; Lee et al., mixed with yeast (10:1 w/w) that was covered 2002). by a fine mesh cloth for ventilation. The The present study was conducted to cultures were maintained in the dark in a investigate the potential effects of essential oils growth chamber set at 27 ± 1 ºC and 65 ± 5% extracted from the aerial parts of A. RH. One to seven days old adults were used for khorassanica, R. officinalis and M. longifolia fumigation toxicity tests and repellency on the confused flour beetle, T. confusum. bioassays. All experimental procedures were Although a number of researchers have shown carried out at the same environmental condition the effectiveness of essential oils and their as those of the culture. constituents against adults of various stored grain insects, there are no reports on toxicity of Fumigant toxicity tests A. khorassanica and M. longifolia on T. To determine the fumigant toxicity of essential confusum oils, filter papers (2 cm diameter) were impregnated with oil at doses calculated to give Materials and Methods equivalent fumigant concentrations ranging from 185 to 1111 µl /l air for all essential oils Plant materials tested. Afterwards, the impregnated filter paper Aerial parts of A. khorassanica, R. officinalis was attached to the under surface of the screw and M. longifolia were collected at full cap of a glass vial (volume 27 ml). The caps flowering stage from Pole Chehel Dokhtar were screwed tightly on to the vials containing Downloaded from jcp.modares.ac.ir at 19:01 IRST on Friday September 24th 2021 (Khorassan province), Karaj (Tehran province) 10 (1 to 7 days old) adult insects each. Each and Yoush and Baladeh (Mazandaran concentration and control was replicated five province), from August to November 2007 and times. Adults were exposed to each essential oil authenticated by Mozaffarian, Herbarium at concentration of 185.2, 370.4, 740.7 and Department, Research Institute of Forests and 1111.1 µl /l air for 3, 6, 9, 12 and 24 h. Rangelands of Iran. Mortality for each concentration and exposure Plant parts were let dry naturally on time was checked independently. Insects were laboratory benches at room temperature (23-27 presumed dead if they remained immobile and ºC) for 7 days until they were crisp. The dried no leg or antennal movements were observed. materials were stored at – 24 ºC until needed and Analysis of variance (ANOVA) was used to then hydrodistilled to extract their essential oils. compare treatments in each experiment. Differences between the means were Extraction of essential oils established by Tukey’s test at 5% level (SAS Plant materials were milled into fine powder Institute, 1997). using a milling machine. Fifty grams of the Another experiment was designed to plant samples to which 600 ml distilled water determine median effective time to kill 50% of was added, were subjected to hydrodistillation adults (LT50 values) at 740.7 and 1111.1 µl/l air 24 Saeidi and Moharramipour __________________________________________ J. Crop Prot. (2013) Vol. 2 (1) of the respective oils. The mortality was Fifty nonsexed adults (1-7 days old) of flour assessed by direct observation of the insects beetles were introduced into the center of each every hour for up to end point of mortality. main chamber. Central chamber was covered by Time-mortality data for each experiment were plastic screen but the treated and control analyzed by Mathematica software 6.0 (Throne chambers were covered by lids and the whole set et al., 1995) with time as the explanatory up was left in darkness. After 4 h, the number of variable to derive estimated hours for 50% adult beetles at each chamber was counted and the mortality. percentage repellency (PR) values were After initial dose setting experiments computed using the formula of Liu et al. (2006): ⎛ C − E ⎞ another set of bioassay tests was designed to %PR = ⎜ ⎟×100 T assess 50% lethal concentration (LC50) as ⎝ ⎠ described by Negahban et al. (2006). Tribolium where C is the number of insects in control, E is confusum were exposed to the essential oil of A. the number of insects in oil treated chamber and khorassanica at 10.71, 17.85, 25, 32.14 and T is the number of total released insects. 39.28 µl/l air for 24 h, without solvent. The Analysis of variance (ANOVA) was used to concentrations of 7.14, 14.28, 21.42, 28.5, determine the effect of essential oil 35.71 µl/l air were used for R. officinalis, concentrations on repellency. Arcsine square- followed by 9.25, 18.51, 27.77, 37.03, 46.29, root transformation was performed on 55.55, 64.81 µl/l air for M. longifolia. Control percentage repellency. Following a significant insects were kept without any essential oil. ANOVA, differences between the means were Each test was replicated five times. After 24-h determined by Tukey’s test at 5% level. exposure period, the number of dead and live insects in each bottle was counted. Probit analysis (Finney, 1971) was used to estimate Results LC50 values with their confidence limits by SAS 6.12 (SAS Institute, 1997). Significant Fumigant toxicity differences between LC50 values were Bioassay tests were conducted to determine if determined by estimation of confidence the insecticidal activity of A. khorassanica, R. intervals of the relative median potency using officinalis and M. longifolia oils against T. SPSS version 18. confusum adults was attributable to their fumigant action. No dead insects were observed Downloaded from jcp.modares.ac.ir at 19:01 IRST on Friday September 24th 2021 Repellency bioassay in controls.