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

Spodoptera exigua (Hübner) was studied in laboratory (۲۵±۱ºC, ۶۰±۵% RH, and ۱۶:۸ L:D h) exploring the antibiotic effects of ۱۰ canola cultivars (Sarigol, SLM۰۴۶, Hayula۴۲۰, RGS۰۰۳, Opera, Okapi, Licord, Modena, Zarfam and Talaye) on its demographic parameters. The age-stage, two-sex and the traditional female age-specific life tables were constructed by using the demographic data. The larval period was longest on Modena (۱۷.۵۳ days) and pupal period was longest on Opera (۸.۹۶ days). The longest and shortest development time of immature stages lasted ۲۹.۹۶ and ۲۵.۸۲ days on Talaye and Okapi, respectively. Male adult longevity was longest on Okapi (۱۴.۹۳ days) and shortest on Hayula۴۲۰ (۹.۱۴ days), and female adult longevity was longest on Zarfam (۱۸.۰۴ days) and shortest on Hayula۴۲۰ (۸.۰۷ days). Based on the two-sex life table, the net reproductive rate (R۰), intrinsic rate of increase (r), and finite rate of increase (λ) were highest on Okapi (۳۵۲.۹۶ offspring per individual, ۰.۲۰۱ and ۱.۲۲۳ day-۱, respectively). The lowest of R۰ was recorded on Opera (۱۵۲.۷۳ offspring per individual) and lowest of r and λ on Talaye (۰.۱۴۲ and ۱.۱۵۳ day-۱, respectively). The mean generation time (T) took longest time on Modena (۳۶.۴۱ days) and shortest on Okapi (۲۹.۰۶ days). The results of this study showed that ‘Okapi’ was the most suitable canola cultivar for reproduction and population growth of S. exigua, which revealed higher susceptibility of ‘Okapi’ to this pest.

Keywords:

beet armyworm , Two-sex life table , Population growth