Life history of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), on four potato varieties in Iran

Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say),is the most important insect pest of potato in Iran. If local potato varieties vary in susceptibility to the pest, host plant resistance may provide management benefits to potato growers. A life table study was carried out to determine the relative suitability of four common potato varieties (Agria, Marfona, Savalan and Satina) for CPB development and reproduction in northwest Iran under laboratory conditions at 23 ± 3 ºC, 62 ± 10% RH, and natural photoperiod. Developmenttime and hence generation time was longest on Savalan (31.07 ± 0.48 d and 42.72 ± 0.71 d respectively) and shortest on Agria (27.8 ± 0.65 d and 35.99 ± 0.8 d respectively). Juvenile mortality was highest (47.5%) on Satina and lowest (22.5%) on Marfona. Intrinsic rates of increase (r) were 0.129 ± 0.005, 0.127 ± 0.005, 0.129 ± 0.006 and 0.104 ± 0.004, on Agria, Marfona, Satina and Savalan, respectively, that on Savalan being significantly lower than the others.The highest net reproductive rate was 145.26 ± 25.23 on Marfona and the lowest was 81.18 ± 2.71 on Savalan which was not significantly different among the cultivars. It seems that, among the four tested cultivars, the Savalan cultivar is less suitable to CPB, resulting in the poorest overall biological performance of the beetle, but the level of resistance did not appear sufficient to negate the need for other control methods.