Control potentials of some entomopathogenic nematodes against Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, 1951 (Hymenoptera: Cynipidae)

The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, 1951 (Hymenoptera: Cynipidae), has spread rapidly worldwide and can cause 80% product loss in chestnut. In the chemical control insecticides are ineffective because the larvae of the insect are well protected inside the chestnut galls. Various parasitoids of D. kuriphilus have been reared in Europe. However, native European parasitoids cannot keep the D. kuriphilus population below the economic threshold. The purpose of this research was to determine the potential of some entomopathogenic nematodes (EPNs) as an alternative biological control agent. Although EPNs have not been studied on D. kuriphilus until now, it is known that EPNs can infect some above-ground pests. In this study, two strains of Steinernema feltiae Filipjev, 1934 (Rhabditida: Steinernematidae) and one strain of Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae) with the four dosages were applied against D. kuriphilus adults in both chestnut shoots and petri dishes. The study was conducted in 2019 under laboratory conditions in Bursa (Turkey). The results of the study indicated that the EPNs can infect D. kuriphilus adults. In addition, the numbers of egg laying of D. kuriphilus adults exposed to the EPNs decreased.