تاثیر ارقام مختلف لوبیا روی وزن پیش ‏شفیره، شفیره و واکنش‏ های تغذیه‏ ای Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae)

The cotton leafworm, Spodoptera littoralis (Boisd) is one of the most important pests of crops. This pest can be controlled by the widespread use of chemical compounds, which can increase the pest resistance against pesticides. In this study, effect of various bean cultivars including cowpea (1057 and Mashhad cultivars), common bean (Sadri, Saleh, Ghaffar and Arabi cultivars), white bean (Dorsa and Almas cultivars), red bean (Yaghout, Ofogh and Dadfar cultivars) on pre-pupal, pupal and feeding responses of sixth instar larvae of Spodoptera littoralis (Boisd) based on dry weight, was investigated under laboratory conditions (25 ± 1C, 65 ± 5% RH and a photoperiod of 16:8 L:D). The data were analyzed via one-way analysis of variance (ANOVA) using the statistical software of SPSS ver. 22. The statistical differences among means of various bean cultivars were compared through Turkey’s post hoc Honestly Significant Difference (HSD) test at α= 0.01. The findings revealed that the larvae fed on cowpea Mashhad cultivar had the lowest pre-pupal (34.020 mg) and pupal (41.820 mg) weights compared with the other cultivars. However, the highest pre-pupal (43.671 mg) and pupal (54.300 mg) weights were in the larvae reared on common bean Arabi cultivar. The results of feeding responses of sixth instar larvae of S. littoralis explored that larval weight and larval gain weight were the highest on common bean Arabi cultivar (57.873 and 15.437 mg, respectively) and the lowest on cowpea Mashhad cultivar (48.953 and 8.999 mg, respectively). Also, the highest value of food consumed was on common bean Sadri cultivar (69.515 mg) and cowpea Mashhad cultivar (68.061 mg), whereas white kidney bean Dorsa cultivar (39.058 mg) had the lowest value of it. Furthermore, the highest feces produced was on larvae reared on cowpea Mashhad cultivar (40.677 mg). According to the results, cowpea Mashhad cultivar was the most unsuitable cultivar for S. littoralis, probably due to the presence of some secondary chemicals which had an adverse effect on the digestive system of the pest.