Department of Plant Protection, College of Agriculture and natural resources, University of Tehran, Karaj, Iran,
Feeding indices of the key pest of pomegranate orchards in Iran, carob moth (Ectomyelois ceratoniae (Zeller)), were studied under controlled conditions (27 ± 2 °C, 75 ± 5% RH, and 16:8 h L:D) on an artificial diet treated with three concentrations (100, 200, and 300 µl / gdiet) of wood vinegar (Pyroligneous acid). Artificial diets treated with 100, 200, and 300 µl / gdiet of distilled water, were considered as control treatments. Ten larvae (second stage) were weighed as a group, added to each container. There were six replicates of each treatment concentration and control. Feeding indices of carob moth larvae differed significantly on three concentrations of wood vinegar (P < 0.0001). The highest amount of relative growth rate (RGR) was obtained by 100 µl / gdiet concentration of wood vinegar (0.415 ± 0.046 mg mg-1, daily), while 300 µl / gdiet concentration had the lowest of RGR (0.028 ± 0.051 mg mg-1, daily). The relative consumption rate was calculated to be 24.196 ± 1.782, 83.80 ± 4.052, and 63.128 ± 3.909 (mg mg-1, daily) on 100, 200, and 300 µl / gdiet of wood vinegar, respectively. Carob moth larvae reared on the artificial diet with 100 µl / gdiet of wood vinegar illustrated the highest efficiency of conversion of ingested food (ECI) (1.778 ± 0.287 mg mg-1, daily), whereas ECI had the lowest number on 300 µl / gdiet concentration of pyroligneous acid (0.046 ± 0.029 mg mg-1, daily). Moreover, E. ceratoniae larvae reared on the artificial diets with 300 and 200 µl / gdiet of wood vinegar showed the highest percentage of mortality (46.666 ± 3.333% and 40 ± 4.472%, respectively). Results showed that pyroligneous acid would be an effective organic compound (such as natural pesticide) on carob moth larvae as the larvae spend their early stages in pomegranate crowns and then bore into the pomegranate. Therefore, using wood vinegar in the right time could reduce the pest damage in pomegranate orchards.