Abstract:
The filbert aphid Myzocallis coryli (Goeze) is a serious pest of hazelnut in North America, Italy, Spain, and Turkey. To evaluate the resistance of hazelnut to this insect, aphids were reared on five major cultivars ('Tombul,' 'Palaz,' 'Cakildak,' 'Fosa,' and 'Mincane') under laboratory conditions. The developmental times of preadult and adult stages, total longevity, reproduction, and life table parameters were analyzed according to age-stage, two-sex life table theory, in which the stage differentiation and variable developmental rates among individuals could be described. The intrinsic rate of increase (r) and finite rate of increase (lambda) varied among the cultivars. The highest values were found for aphids reared on Cakildak (r = 0.2019 d(-1), lambda = 1.2238 d(-1)), which did not differ significantly from Mincane (r = 0.1957 d(-1), lambda = 1.2161 d(-1)), whereas these parameters were lowest for Palaz (r = 0.1622 d(-1), lambda = 1.1761 d(-1)) and Fosa (r = 0.1677 d(-1), lambda = 1.1826 d(-1)). Based on longer preadult development time, shorter adult longevity, shorter reproductive period, together with the demographic parameters, Palaz and Fosa provide a relatively unfavorable environment for the filbert aphid. The results obtained from demographic data together with estimates of pest growth potential generated by computer projection based on age-stage, two-sex life table theory, demonstrate that both Palaz and Fosa are resistant cultivars for M. coryli and can be considered in hazelnut integrated pest management and hazelnut breeding programs.