Thermal requirements of immature stages of pistachio psylla, Agonoscena pistaciae (Hemiptera: Psyllidae) in natural conditions of Rafsanjan, Iran

The pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer, is a major pest of pistachio trees throughout pistachio producing regions in Iran. Nowadays, degree-day models are considered as one of the most important tools in integrated pest management and forecasting of pest status. The cumulative effective temperatures were calculated for different percentages of nymph based on the lower development threshold of 9.96oC and upper development threshold of 32.5oC and different biofix during years 2007 and 2008 under field conditions. The cumulative effective temperatures form 21 January to 75 percentage of nymphs for first generation was calculated 510 DD. To calculate the cumulative effective temperatures for generations 2 to 6, 75% of nymph of last generation was selected as biofix. The cumulative effective temperature for generations 2 to 6 based on 75 percentage of last generation was calculated 339, 333, 313, 389 and 337 DD respectively. The mean cumulative effective temperature from 75 percentages of nymphs of each generation to next generation was calculated 342±28.13 degree-day. By using degree-day model, we can determine the suitable control time of pistachio psylla.