Fumigant Toxicity on Adults of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) of Essential Oil from Rosmarinus officinalis L. and its Side Effects on Chickpea Grains

In this study, fumigant effect of essential oil of Rosmarinus officinalis L. against adults of Callosobruchus maculatus (F.) was assessed. In addition, vapor effects of rosemary essential oil to odor and germination of edible and seed chickpea grains were investigated. This study was performed at 28 +/- 2 degrees C, % 55 +/- 5 (RH: relative humidity) and dark conditions. The essential oil of R. officinalis was obtained by hydrodistillation. It was analyzed by gas chromatography-mass spectrophotometry (GC-MS). Borneol (25.67%), verbenone (23.55%), camphor (20.48%), 1,8-cineol (5.76%) and alpha-terpineol (5.61%) were major components of the essential oil. The highest adult mortality rate was determined as 97% after 24 hours at 25 mu l/l air dose. Lethal concentration values (LC50 and LC90) at 12 and 96 hours were determined as 25.71, 42.58 and 10.98, at 13.34 mu l/l(-1) air, respectively. Lethal time values (LT50 and LT90) were found as 114.82, 208.45 hours at 10 mu l/l(-1)air and 15.89, 35.95 hours at 20 mu l/l(-1) air dose. The highest dose (60 mu l/l(-1)air) applied and the longest exposed time (72 h) did not show any negative effect on germination of chickpeas. A distinct smell has been determined on chickpeas which were exposed to the essential oil. As a result, it was determined that rosemary essential oil can be used as potential bio-fumigant in control of C. maculatus in chickpea seeds. Also if the smell of rosemary essential oil vapor is removed, the chickpea can be used as edible.