Studies on the gall characteristics of dryocosmus kuriphilus in chestnut genotypes in Yalova and Bursa provinces of Turkey

Abstract

The Asian chestnut gall wasp Dryocosmus kuriphilus is a global pest of chestnut (Castanea spp.). It has been spreading in Turkey's forests and orchards since 2014. This pest imposes a big threat to the Turkish chestnut industry, which is among the top producers in the world. Its gall morphology has been related to pest pressure and host cultivar, thus eventually modulating plant damage with heavy impact on growth and fruit production. We compared gall characters (position on plant organ, ratios, dimensions, volumes, number of larval chambers) in wild Castanea sativa, two local cultivars and a Euro Japanese hybrid. Overall, leaf galls were more common (55.36%), followed by the stem (19.6%) and leaf stipule galls (15.29%). The mean number of chamber and volume value of gall types were 1.52-5.93 and 0.43-2.15 cm(3), respectively. The highest values were observed in 'stem gall'. The more gall formation was observed in the wild chestnut trees and 'Marigoule' than the other local varieties.