Document Type : Research Paper
Authors
Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
Abstract
Red flour beetle Tribolium castaneum isa major pest of stored products especially cereal flour depreciating the quantity and quality of the food economically. The application of repellents could be considered as a new control method in storage. In this study repellent activity of extracts from leaf, red and white flowers of Nerium oleander, Lavandula officinalis leaves and Ferula assafoetida gum was assayed on T. castaneum. Experiments were conducted in dark condition at 27±1ºC and 70-80% RH. To determine percentage repellency (PR), filter paper disks were impregnated with different concentrations of plant extracts. Each filter paper was divided into two equal parts. Then, each half-disk was separately added by extract dilutions (1.99, 3.98, 11.94, 19.90 and 27.78 μl/cm2) or acetone as control. Each treated half-disk was then attached lengthwise edge-to-edge, to a control half-disk with adhesive tape and placed in a petri dish (8cm diam.). Twenty adult insects were released in the middle of each filter paper, and the insects that settled on each half, were counted after 1 h and then at hourly intervals for 5h. The results showed that the repellency of Ferula gum was significantly higher than that of remaining extracts. The highest PR (98.75%) was observed in the Ferula gum in the concentration of 27.78 μl/cm2. While, the lowest PR (5.5%) was shown in the Lavandula leaf extract in 1.99 μl/cm2. Repellency increased with concentration in all cases, the repellent effect did not decreased with time over the 5-h experimental period.
Keywords
)