مقاومت هفت رقم تجاری چغندر علوفه‌ای به کرم برگخوار چغندر، Spodoptera exigua (Hubner)، در شرایط آزمایشگاهی

Beet armyworm, Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae), is one of the important pests of fodder beet, Beta vulgaris L., which strongly affects its yield. Investigating the effect of plant cultivars on biological parameters, especially the development process, mortality and reproduction of insect pests, is one of the essential studies needed in integrated pest management. So, in the current study, development and demographic parameters of this insect on seven commercial fodder beet cultivars including Kyros, 1025, Geryty kws, Alianka, Laciana kws, Kara and Enermax was investigated under laboratory conditions (27 ± 1 ° C, 65 ± 5 RH%, 16:8 L:D). Data analysis was performed based on age-stage two-sex life table theory using TWO-SEX-MSChart software. Mean and standard error of life table parameters were calculated using bootstrap approache; paired bootstrap method was used to compare the means. For this purpose, 70 less than one-day-old eggs were selected from a laboratory generation which developed on the related fodder beet cultivars. The development, mortality and oviposition was recorded daily until the death of the last individual. Results revealed that the developmental period of all the immature stages was significantly affected with these cultivars; the shortest and longest total developmental period were 23.79 and 33.25 days on 1025 and Laciana kws, respectively. The lowest and highest percentage of immature mortality were related to 1025 (11.43%) and Kyros (62.86%), respectively. The longest and shortest adult longivity with 10.66 and 8.5 days obtained on Kyros and 1025 cultivars, respectively. Insects reared on Alianka had the longest preoviposition period (3.90 days). The highest number of female oviposition (933.04 eggs) was obtained by feeding on Enermax cultivar. Results revealed that the most and least value of net reproductive rate (R0, offspring/indivdual) belonged to Alianka (385.81) and Laciana kws (110.97), respectively. The intrinsic rate of increase (r, day-1) of pest reared on theses cultivars was 0.1492, 0.2139, 0.1603, 0.1802, 0.1250, 0.1563 and 0.1929, respectively. The highest finite rate of increase (λ) with significant difference was related to 1025 cultivar (1.238 day-1). The results showed that among these cultivars, 1025 and Laciana kws cultivars are the most sensitive and resistant cultivars to beet armyworm, respectively. These results can be used in the management programs of beet armyworm in different fodder beet cultivation areas.