Estimations of the critical temperatures for development of the pistachio psylla, Agonoscena pistaciae (Hemiptera: Psyllidae)

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 degrees C. The relationships between temperature and developmental rates were described by linear and the non-linear Lactin models. These models were evaluated based on R-2, RSS, AIC and R-adj(2). 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 degrees C, respectively, and based on the Lactin model was 8, 11.55 and 11.2 degrees 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.