Comparison of common pistachio psylla (Agonoscena pistaciae) population on main native and non- native pistachio varieties in Khorasan Razavi Province

The common pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hem.: Psyllidae), is considered as a common pest of pistachio orchard in Iran and also as a major pest in Khorasan Razavi province. So far pesticides as a main method to control of the pest were not satisfactory. The use of resistance cultivars is important in the pest management programs. In this study, the population of different age stages of common pistachio psylla were assessed on six pistachio cultivars (Badami Sefid, Ghermez, Barg Siah, Kale Ghuchi, Akbari, Fandoghi) in Faiz abad region (Khorasan Razavi province) during 2010 and 2011. Sampling was carried out on four trees for each cultivar in 10-12 days intervals. The populations of egg and nymph stages were recorded in laboratory through cut leaves. The limb tapping method was used for adult density evaluation. According to the results, there was not significant interaction between year and cultivars (p>0.01). The results showed that there were significant differences among egg densities on examined cultivars, ranged from 3.4±0.013 eggs on Badami Sefid to 12.35±0.044 eggs on Ghermez cultivar. The lowest and highest nymph population was recorded on Badami Sefid (2.19±0.013) and Ghermez (8.77±0.033), respectively. The mean population of adult was significantly different on cultivars, in which, Ghermez (4.26±0.026) and Kale Ghuchi (4.15±0.038) had the highest density of adult population. The results revealed that there might be some physical or chemical sources of resistance in Badami Sefid and Barg Siah cultivars which make them unsuitable for different stages of the pest and reduce their population. These results could be prerequisite for determining the resistant cultivars and a successful IPM program for the pest.