The green shield bug, Palomena prasina (Hemiptera: Pentatomidae), is a pest of deciduous trees and shrubs throughout Turkey and is found in a large variety of habitats, including gardens. We investigated the facultative cultivable bacterial flora of 10 healthy and 5 dead green shield bugs, collected from the vicinity of Trabzon, Turkey, and tested them for insecticidal activity. Based on the conventional and molecular tests, 12 different bacteria were isolated and identified as Curtobacterium sp., Rhodococcus sp., Arthrobacter nicotinovorans, Arthrobacter oxydans, Agrococcus jejuensis, Pseudomonas poae, Raoultella terrigena, Serratia sp., Lysinibacillus sphaericus, Stenotrophomonas rhizophila, Bacillus thuringiensis and Microbacterium oxydans. Mortalities due to the application of 0.5 mL of L. sphaericus, B. thuringiensis and R. terrigena at a density of OD600 1.89 were 60%, 70% and 60%, respectively, on adult P. prasina. This indicates that facultative cultivable bacterial flora isolated from P. prasina have potential for microbial control of this pest.