Variation in populations of common pistachio psyllid,Agonoscena pistaciae (Hem.: Psyllidae),with different chemical control levels: Narrower wing shape in the stressed environment

The common pistachio psyllid,agonoscena pistaciae burckhardt & lauterer (hemiptera: psyllidae),is a key pest of pistachio trees in iran. both psyllid nymphs and adults directly damage pistachio; they extract large quantities of sap from tree and produce honeydew and cause deformation of leaves resulting in great economic damage. little is known about the intraspecific variation of common pistachio psyllid in regions with stressed conditions,such as areas under high levels of pesticide application. therefore,this study using geometric morphometrics was designed to 1) evaluate morphological differences in wing shape in populations under different levels of pesticide application in kerman province as the main pistachio producer in the world,and 2) search for a link between the morphological data and previously studied molecular data. the populations were collected from regions with high and low pesticide applications. the results showed that wing shape (p < 0.01) and size (p < 0.01) are different between populations exposed to different chemical control programs. based on the results,narrower wing shape was found in psyllid population in stressed environment (population with extreme chemical control programs). in spite of allometric growth,significant shape differences still remain when the data are adjusted to constant size,which showed the important role of genetic changes in the observed morphological changes. moreover,links between morphologic and previously studied molecular data were revealed. based on the results,it appears that an evolutionary resistance process is developing,therefore insecticide resistance management programs,in the regions under investigation,is recommended. © 2017,tarbiat modares university. all rights reserved.