Potential four entomopathogenic nematodes for the control of Brown marmorated stink bug - Halyomorpha halys

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) (BMSB) is an exotic invasive insect for Italy and Georgia. At present BMSB is very active and makes alarming situation. Pest characterized by the massive increase and formation the large tracts of agrocenosies and urban area (inducing foliage, coniferous, ornamental plants as well). At present, BMSB has become a key pest in many crop and makes grate economical loses. Nowadays, due to lack of specific natural enemies, population density of this insect is not controlled by them. The aim of our study was to established potential entomopathogenic nematodes (EPNs) and determine their effectiveness on H. halys for its control. In experimental trial four entomopathogenic nematodes were used: two of Georgian species Heterorhabditis bacteriophora (HRB, GEO) and Steinernema borjomiensis; two Italian species Heterorhabditis bacteriophora (HRB, IT) and Steinernema apuliae. In laboratory assay (22°C and 80% RH), the mentioned nematodes were used in the following concentrations: 1:1000, 1:500, 1:200 infective juveniles (IJs) per adult of H.halys. The mortality of tested insects was estimated from the third day after treatment. Significant differences were observed between Georgia and Italian species. HRB (GEO) and S. borjomiensis at the high concentration -1:1000, mortality 46.6% -33.3%, in case 1:500 - 33.3%-32% and in 1:200 - 33.3%-13.3% were reached accordingly. More pathogenic were Italian species. HRB(IT) and S. apuliae in high concentration -1:1000, mortality achieved 93.3% -53.3% in case 1:500 - 93.3%-40%, and in 1:200 - 73.3%-33.2% were observed respectively. The emerging IJs were harvested and counted throughout the interval of 11-15 days.