Life table of grape phylloxera on some irradiated in vitro cultured rootstocks

The life table of local strain of grape phylloxera on the most commonly used rootstocks; Ru140, R99 and 3309 C and one local variety Helwani, which were in vitro cultured and treated with low doses of gamma irradiation was determined. Additionally, the effect of different concentrations of IAA on reproduction and development of phylloxera, which infested the roots of our local grape variety Helwani, was evaluated. Our results showed that the life table of grape phylloxera was different between irradiated and unirradiated in vitro plants. The survival, fecundity and developmental time were reduced by applying irradiation. Thus, low doses of gamma irradiation increased grape resistance to phylloxera. The was a positive effect of of IAA on the resistance of Helwani to phylloxera when it was infested at old age (80-d-old). However, the susceptible of Helwani to phlloxera was increased when it was infested at young age (40-d-old). The present study provides good information on the possibility of using irradiation and hormone to increase the resistance of grape to phylloxera.(author)