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

Abstract

The aim of this study was to evaluate the effect of ten d ifferent 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 (H M 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 foo d (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 i n (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 t hat (7112*SB36)*Sh - 1 - HSF - 5 was the most suitable host for S. exigua that should be considered in cultivation or breeding programs. Keywords: Antibiosis, Beet armyworm, Food consumption, Insect weight.