Bottom-Up Effect of Different Host Plants on Plutella xylostella (Lepidoptera: Plutellidae): A Life-Table Study on Canola

The effects of 10 commercial canola, Brassica minus L., cultivars widely grown in Iran-'SLM046', 'Opera', 'Okapi', 'RGS(003)', 'Modena', 'Sarigol', 'Zarfam', 'Licord', 'Hayula(420)', and 'Talaye'-on the demographic parameters of diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), were determined. The experiments were conducted in a growth chamber at 25 +/- 1 degrees C; 65 +/- 2% RH, and a photoperiod of 16:8 (L:D) h. The comparison of intrinsic rate of natural increase (r(m)), net reproductive rate (R-0), and the survival rate of adult stage of P. xylostella on 10 canola cultivars suggested that this pest performed best on SLM046. The r(m) value of P. xylostella ranged between 0.241 on RGS(003) and 0.304 on SLM046. The R-0, finite rate of increase (lambda), mean generation time (T), and doubling time (DT) values of P. xylostella on SLM046 were 52, 1.35, 13.4, and 2.35 and on RGS(003) were 31, 1.27, 14.4, and 2.94, respectively. The Weibull model adequately described the shape of the survivorship curve of adult P. xylostella from life-table data. A significant fit was obtained with the Weibull model for P. xylostella in all experimental canola cultivars. As a result, SLM046 Opera, and Hayula(420) were the most suitable hosts and had least negative impact on life-history statistics of the pest.