Life table studies for Phthorimaea operculella (Zeller) were carried out on four
potato varieties, namely Atlas, Spunta, Simone and Nicola to evaluate the preferred
variety for feeding Ph. operculella larvae. The calculated biological parameters viz.
Net reproductive Rate (R0), Generation time (Gt), Intrinsic Rate of Increase (rm),
Finite Rate of Increase (λ) and Population Doubling Time (Dt) indicate that Atlas
proved to be the quite favorable for achieving the highest developmental and
multiplication rates of Ph. operculella, followed by Simone and Spunta, meanwhile
Nicola was the least favorable data figure in this respect were obtained.
The natural mortality figures; Apparent Mortality (AM), Real Mortality (RM),
Indispensible Mortality (IM), Mortality-Survivor Ratio (MSR) and log population and
k factor for larvae reared on Atlas variety were 41.86, 36, 22.32, 4.42, 2.54 and 0.24
respectively, the values 32.89, 25, 13.72, 1.55, 2.48 and 0.17 were obtained for
Simone, the values 43.75, 35, 21.77, 3.11, 2.50 and 0.25 for Spunta and 51.19, 43,
22.02 and 5.51for Nicola.
For pupae similar natural mortality trends were observed when Ph. operculella
larvae were fed on Atlas, 38, 19, 19, 3.77, 2.30 and 0.21, while these values were
45.10, 23, 23, 2.6, 2.31 and 0.26 for Simone. The corresponding values on Spunta
were 37.78, 17, 17, 2.43, 5 and 2.21 and 48.78, 20, 20 and 5 for Nicola.
It could be concluded that Nicola is the least susceptible variety for infestation;
while Atlas is the most favorable variety for feeding Ph. operculella for research
purposes.