Spatial mapping of the common pistachio psylla, Agonoscena pistaciae: A case study in the Rafsanjan region, Iran

The common pistachio psylla Agonoscena pistaciae is a key pest of pistachio in Iran. A study was conducted to determine the spatial distribution of psylla nymphs and eggs in a 10 ha pistachio orchard in the Rafsanjan region, southeast of Iran. Three rows, each containing 33 trees (totally 99 trees), were randomly selected in the orchard based on a stratified sampling scheme. In each of the selected trees, three positions in the crown (top, middle and bottom) were considered. One leaf from each position as sampling unit (totally 297 samples) was clipped and number of nymphs and eggs were counted. Ordinary kriged maps were achieved for nymphs and eggs of the three positions using a variogram function. Results indicated the highest and lowest density of the nymphs occurred on the top and bottom positions of the crown, respectively. Eggs of the common pistachio psylla were laid mostly on the bottom of the pistachio crown.