Effect of different leafy vegetables on the biological and population growth characteristics of the cotton leafworm, Spodoptera littoralis (Boisd)

Abstract

The cotton leafworm, Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae), is an important and polyphagous pest that causes considerable damage to agricultural crops in Iran and many other parts of the world. In this research, the effects of seven different leafy vegetables, including Purslane, Chives, Parsley, Basil, Dill, Coriander and Mint were assessed on the biological and life table parameters of S. littoralis at 25 ± 2°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) hours. The longest development period was in the insects fed on Purslane (40.67 ± 9.49 days), and the shortest was obtained on Basil (30.22 ± 0.42 days) and Coriander (30.76 ± 0.32 days). The lowest value of fecundity was on the Purslane (199.32 ± 21.82 eggs), and the highest was recorded on the Coriander (481.06 ± 62.82 eggs), Basil (428.97 ± 28.68 eggs) and Chives (409.26 ± 26.58 eggs) vegetables. In addition, the results of demographic parameters showed that the intrinsic rate of increase (r) and net reproductive rate (R0) of S. littoralis were lowest on the Purslane (0.124 ± 0.072 day-1, and 67.92 ± 17.51 offspring, respectively), and highest values were observed on the Coriander (0.161 ± 0.064 day-1, and 275.70 ± 53.94 offspring, respectively). The cluster results indicated that Coriander was relatively susceptible host for feeding of S. littoralis. In contrast, the Purslane was found the relatively resistant (least appropriate) host for this pest, which could be useful in the development of integrated pest management strategies, and understanding plant-herbivore interactions.

Keywords

• cotton leafworm
• plant resistance
• two-sex life table
• leafy vegetables
• integrated pest management