Influence of different host plant cultivars on nutritional indices of Plutella xylostella (Lepidoptera: Plutellidae)

The diamondback moth, Plutella xylostella (L.) is a serious and economically important pest of cruciferous crops worldwide. The nutritional indices of this pest on four host plants including two canola (SLM046 and RGS003) and two cabbage cultivars (Green-Cornet and Glob-Master) were determined under laboratory conditions (25 ± 0.5 °C, 65 ± 5% RH and 16: 8 L: D h). The highest relative consumption rate (RCR) and relative growth rate (RGR) were recorded on RGS003 (95.68 ± 14.52 mg/mg/day) and SLM046 (0.382 ± 0.041 mg/mg/day), respectively. The efficiency of the conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were significantly higher on SLM046 (2.298 ± 0.646 and 2.471 ± 0.719%, respectively). However, there was no significant difference among cultivars regarding approximate digestibility (AD) index. The highest feeding performance of the larvae of P. xylostella was found on SLM046. The nutritional indices are appropriate tools in host plant resistance evaluation and they also could provide profound understanding of the behavioral and physiological bases of insect-host plant interactions.