Susceptibility of potato plants grown from tubers irradiated with stimulation doses of gamma irradiation to potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae)

The feeding behaviour of potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae), reared on leaves and tubers of potato plants, which were irradiated as seed (tubers) with stimulation doses of gamma irradiation (1, 3, 5 and 10 Gy), was studied. Significant differences in the larvae and pupae developmental time, pupal weight, mortality, fecundity and percentage egg hatch, were observed between insects fed on plants which resulted from the irradiated seeds and those of the control. It appears that leaves of potato plants grown from irradiated seeds particularly those of 3 Gy, became more attractive to the larvae, although the resulting tubers, with the exception of those of 10 Gy, became more resistant to potato tuber moth. Storing the tubers at ambient temperature conditions affected the degree of larval sensitivity. The leaves and tubers of 10 Gy-irradiated seeds became more suitable for insect development, indicating that the later dose may inhibit the production of secondary plant metabolities and chemical compounds.