The pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae), is a major pest of pistachio trees throughout the pistachio producing regions in Iran. The effect of temperature on the developmental rates of eggs and nymphs of A. pistaciae was determined at different constant temperatures, i.e. 15, 20, 25, 30, 32.5 and 35 ± 0.5°C. The relationships between temperature and developmental rates were described by linear and the non-linear Lactin models. These models were evaluated based on R2, RSS, AIC and R2adj. The estimated value of the lower temperature threshold for egg, nymph and egg to adult development based on the linear model was 8.06, 10.38 and 9.97°C, respectively, and based on the Lactin model was 8, 11.55 and 11.2°C, respectively. Thermal constants estimated using the linear model, were 88.5, 243.90 and 333.33 DD, respectively, for egg, nymph and egg to adult development. These results indicate that the linear model gives a better description of the relationship between developmental rate and temperature for A. pistaciae than the non-linear model. These results could be incorporated into forecasting models used in the integrated pest management of this pest. and Mohammad Reza Hassani, Abbas Arbab, Hamzeh Izadi, Gadir Nouri-Ganbalani.
Species in the carnea complex of the common green lacewing are predators of the common pistachio psylla, Agonoscena pistaciae in both cultivated pistachio plantations and on wild pistachio plants in Iran. The seasonal occurrence of common green lacewings was monitored in pistachio orchards from 2007 to 2008. In addition, the effect of different temperature regimes on preimaginal development, survival and prey consumption of the predatory lacewing Chrysoperla lucasina fed on A. pistaciae nymphs were studied under controlled conditions. The adults of common green lacewings first appeared on pistachio trees in mid April and were most abundant in early July, decreased in abundance in summer and increased again in October. The relative density of common green lacewings was higher in pistachio orchards where the ground was covered with herbaceous weeds than in those without weeds. In the laboratory females of C. lucasina laid an average of 1085 eggs over 60 days at 22.5°C. The maximum prey consumption occurred at 35°C when the larvae consumed 1812 fourth instar psyllid nymphs during their larval period. The intrinsic rate of natural increase (rm) was 0.11. The total development (egg-adult) required 385 degree-days above the theoretical lower developmental threshold of 9.6°C. and Fatemeh KAZEMI, Mohammad Reza MEHRNEJAD.
The common pistachio psyllid (CPP) is thought to respond to nutrient availability in pistachio trees. We determined the effect of a deficiency of leaf iron (Fe) has on the abundance of the pistachio psyllid at a regional scale. First, we monitored the abundance pistachio psyllid in four pistachio orchards (24 trees as 24 repetitions) located in Maybod County, Yazd province in the centre of Iran and then measured leaf nutrient levels. Orchards were located up to 2.6 km apart. Multivariate regressions were used to determine the relationship between leaf nutrients and CPP population growth. The results indicate that the number of psyllid eggs and population growth rate of the nymphs was negatively correlated with Fe levels in the leaves, while peak numbers of psyllid eggs were positively correlated with the levels of Cu in the leaves. In a manipulative field experiment, we conducted two experiments: (1) pistachio trees treated with iron compared with control trees, and (2) pistachio trees previously treated with iron were treated with ammonium sulphate and compared with trees treated with ammonium sulphate. In the first experiment, psyllids in leaf disc-cages had a significantly greater intrinsic rate of population increase and net reproductive rate on Fe-treated trees than the control trees (Stage 1). In the second experiment, psyllids in leaf disc-cages had similar intrinsic rates of population increase and net reproduction both on the ammonium sulphate treated trees (control) and those previously treated with iron. This indicates that iron may have reacted negatively with nitrogen content of the leaves. In general, these findings indicate that when there is a deficiency of iron in the leaves, the application of nitrogen fertilizer had little effect on the performance of CPP and may have played a minor role in the population dynamics of CPP, but the application of a Fe fertilizer without considering the nitrogen content of the leaves may lead to a population outbreak.