Demographic parameters of the diamondback moth, Plutella xylostella (Lep.: Plutellidae) on five rapeseed cultivars

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Abstract

The diamondback moth, Plutella xylostella (L.) (Lep.: Plutellidae) is one of the most destructive insect
pests of cruciferous crops throughout the world. In this research, the demographic parameters of P. xylostella
were studied on five rapeseed cultivars including Licord, Modena, Okapi, RGsoo3 and REGXkobra. The
experiments were conducted in a growth chamber at temperature of 25 ± 1°C, 60 ± 5% RH and a
photoperiod of 16: 8 (L: D) hr. The mortality of preimaginal stages differed from 47.65 to 65.75% on
Modena and REGXkobra, respectively. The life expectancy of newly laid eggs and one-day-old adults of
P. xylostella was estimated as 13.48, 4.90; 14.69, 10.84; 15.39, 7.72; 16.25, 12.23; 15.06 and 6.05 days
on Licord, Modena, Okapi, RGsoo3 and REGXkobra, respectively. There was significant difference
between net reproductive rates (Ro) of the cultivars. The highest value of Ro belonged to RGsoo3 (74.97 ±
7.99). The longest generation time was on Rgsoo3 while the shortest one belonged to the Modena. The
intrinsic rate of natural increase (rm) on Modena was significantly differed from other cultivars
emphasizing that Modena was the most sensitive cultivar to the diamondback moth than the others.

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