Performance Evaluation of Spodoptera exigua (Lepidoptera: Noctuidae) Larvae on 10 Sugar Beet Genotypes Using Nutritional Indices

The aim of this study was to evaluate the effect of ten different sugar beet genotypes on nutritional indices of the beet army worm, Spodoptera exigua (Hübner) (Lep.: Noctuidae) at 25±1°C, 60±5% RH and a photoperiod of 16:8 (L: D) hour. The sugar beets evaluated in this study included two sugar beet cultivars (HM 1339 RZ and SBSI006), five populations (SB26, SB27, SB29, SB33, SB34), one hybrid (7112*SB36)*Sh-1-HSF-5 and two lines (FC 301 and FC 220). Fourth instar larvae reared on (7112*SB36)*Sh-1-HSF-5 showed the highest Relative Growth Rate (RGR) of 0.31 mg mg^-1 day^-1, Relative Consumption Rate (RCR) of 4.79 mg mg^-1 day^-1 and Approximate Digestibility (AD) value of 94.35% compared with the other host plants. The lowest value of RCR (0.81 mg mg^-1 day^-1) was on SBSI006. The Efficiency of Conversion of Ingested food (ECI) was varied from 1.80% on FC 220 to 9.14% on SB34. The highest AD value of fifth instar (92.63%) was on (7112*SB36)*Sh-1-HSF-5 and the lowest value of this index was recorded on SB27 (83.71%). The highest AD value of whole larval instars was noted in (7112*SB36)*Sh-1-HSF-5 (93.73%). The lowest value of RCR (1.78 mg mg-1 day-1) was found on SB27. The heaviest pre-pupa (81.01 mg), pupa (72.55 mg) and wet adults (19.14 mg) of beet armyworm were recorded on (7112*SB36)*Sh-1-HSF-5. The results indicated that (7112*SB36)*Sh-1-HSF-5 was the most suitable host for S. exigua that should be considered in cultivation or breeding programs.