Life table parameters of Phthorimaea operculella (Lepidoptera: Gelechiidae), feeding on tubers of six potato cultivars.

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is an important and ubiquitous pest of potato, Solanum tuberosum L. (Solanaceae), in both field and stores in the subtropical and tropical zones. The evaluation of potato tubers for susceptibility to potato tuberworm, by measuring its life table parameters, is a valuable component of integrated pest management (IPM). Potato tuberworm life table parameters were investigated in laboratory at 24 +/- 1 degrees C, 65 +/- 5% RH, and a photoperiod of 8:16 (L:D) h on six commonly grown potato cultivar tubers: 'Agria', 'Burren', 'Savalan', 'Marfona', 'Sante', and 'Picaso'. No food was provided to feeding adult moths during experiments. The survival rate on Savalan and Burren potatoes was higher than on other cultivars. The highest reproductive rate was observed on Burren potatoes (50.739 +/- 2.45), although there was one statistical group for net reproduction rate (R(o)). The mean generation time (T(o)) was the longest on the Agria potatoes. The significant difference was observed between intrinsic rates of increase (r(m)) on the potato cultivars. The mean generation time has reciprocal relation with r(m); subsequently, the lowest intrinsic rate of increase was observed on Agria potatoes. The highest and lowest r(m) value was observed on Burren and Agria potatoes, respectively. The descending order of intrinsic rates of increase was on Burren, Savalan, Sante, Marfona, Picaso, and Agria potaotes. The lowest r(m) value indicates that Agria is a relatively insusceptible compared with the other cultivars tested and that this cultivar can be used effectively in sustainable IPM.