A new aphid species record for South Korea, Greenidea (Trichosiphum) prunicola, is reported based on the collection of apterous viviparous females from Castanopsis sieboldii in Tongyeong-si in 2024. This discovery increases the number of known Greenidea species in South Korea to four. Detailed morphological descriptions, measurements, host plants, and distribution data for G. (T.) prunicola are provided. The species is characterized by its glossy reddish-brown body, a body length of 1.70–2.60 mm, a siphunculus that is 0.32–0.37 times the body length, and long, primarily bifurcated dorsal setae. Previous host records include Prunus spp., and its known distribution now includes South Korea, China, and India. A key to the four species of the genus Greenidea now known to be present in South Korea is also provided.
The Genus Greenidea includes 66 species worldwide. Only two species have been recorded in Korea: G.kuwanai and G.nipponica. We collected Greenidea nigra Maki, 1917 on Quercus glauca in Jeju. This species has been recorded in Japan and Taiwan. In this study, we report this species for the first time in South Korea, and describe morphological features of apterous viviparous females.