Antibiotic Resistance of Canola Cultivars Affecting Demography of Spodoptera exigua (Lepidoptera: Noctuidae)

Abstract

Spodoptera exigua (Hübner) was studied in laboratory (25±1ºC, 60±5% RH, and 16:8 L:D h) exploring the antibiotic effects of 10 canola cu ltivars (Sarigol, SLM 046 , Hayula 420 , RGS 003 , Opera, Okapi, Licord, Modena, Zarfam and Talaye) on its demographic parameters. The age-stage, two-sex and the traditional female age-s pecific life tables were constructed by using the demographic data. The larval period was longest on Modena (17.53 days) and pupal period was longest on Opera (8.96 days). The longes t and shortest development time of immature stages lasted 29.96 and 25.82 days on Tala ye and Okapi, respectively. Male adult longevity was longest on Okapi (14.93 days) and sho rtest on Hayula 420 (9.14 days), and female adult longevity was longest on Zarfam (18.04 days) and shortest on Hayula 420 (8.07 days). Based on the two-sex life table, the net reproducti ve rate ( R 0 ), intrinsic rate of increase ( r ), and finite rate of increase ( λ ) were highest on Okapi (352.96 offspring per indiv idual, 0.201 and 1.223 day -1 , respectively) . The lowest value of R 0 was recorded on Opera (152.73 offspring per individual) and lowest value of r and λ on Talaye (0.142 and 1.153 day -1 , respectively). The mean generation time ( T ) took longest time on Modena (36.41 days) and shor test on Okapi (29.06 days). The results of this study showe d that ‘Okapi’ was the most suitable canola cultivar for reproduction and population gro wth of S. exigua , which revealed higher susceptibility of ‘Okapi’ to this pest. Keywords: Beet armyworm, Two-sex life table, Population growt h.