Population parameters of large walnut aphid ([Panaphis Juglandis (Goeze) (Hemiptera: Callaphididae) on some walnut cultivars, and some biological features and predation rates of its important predators

Dusky-veined walnut aphid (Panaphis juglandis) is one of the most important pests in walnut orchards in Lake Van Basin. In this study, population growth parameters of dusky-veined walnut aphid, Panaphis juglandis (Goeze)(Hemiptera: Callaphididae) reared on potted walnut plants of five cultivars of walnut (Akça I, Chandler, Fernette, Fernor, and Pedro) were evaluated under field conditions in the Van region of Turkey in 2011. Additionally, life histories and predation rates of two predators of P. juglandis (Adalia fasciatopunctata revelierei (Mulsant) (Coleoptera: Coccinellidae) and Chrysoperla carnea (Stephen) (Neuroptera: Chrysopidae)) were investigated to obtain basic informations for biological control of the pest. Predators were fed on P. juglandis and maintained in climate chamber providing 25 1 0C, 655% RH, and a photoperiod of 16:8 (L:D) h (5.000 lux) Life table parameters were calculated according to age-stage, two-sex life table for both P. juglandis and its predators. The population growth rate of P. juglandis was significantly affected by the host plants. Due to longer immature developmental time, higher immature mortality rate and the lower total fecundity, the intrinsic rate of increase (r =0.0997 d-1), the net reproduction rate (R0 = 5.90 offspring) and the finite rate of increase (λ = 1.1048 d-1) values were the lowest when reared on the Fernor cultivar, and mean generation time (T= 17.93 d) was the longest. According to results, Fernor creates a less favorable environment for the aphid development and reproduction. Values obtained for the intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0) and mean generation time (T) were 0.103 d-1, 1.108 d-1, 59.91 offspring and 39.72 d, respectively for C. carnea and were 0.1296 d-1, 1.138 d-1, 109.9 offspring and 36.17 d, respectively for A. fasciatopunctata reveliereiNet predation rate (C0= 2039.425 aphids) and finite predation rate (ω) (16.590 aphids) values obtained for A. fasciatopunctata revelierei were found higher than those of C. carnea (net predation rate (C0=143.941aphids; and finite predation rate (ω) =8.125 aphids). For a comprehensive comparison of predation potential of both predators tested, we incorporated both the finite rate and the predation rate into the finite predation rate. When both the growth rate and the predation rate were taken into consideration, our results showed that A. fasciatopunctata revelierei is more efficient than C. carnea as biological control agent for P. juglandis