Interactions between the pine needle gall midge, Thecodiplosis japonensis (Diptera: Cecidomyiidae), and its parasitoids in endemic regions of Korea.
Percentages of pine needle pairs infested by the pine [Pinus] needle gall midge (PNGM), Thecodiplosis japonensis, and percentages of parasitic wasps (parasitoids - Platygaster matsutama and Inostemma spp.) found in PNGM, were surveyed in 24 endemic regions for the pest in the Korea Republic from 1980 to 1997. The data were used to analyse the role of PNGM parasitic wasps in the population dynamics of the pest. Densities of parasitic wasps were directly related to the host densities, reaching their highest density when the percentage of infested needle pairs was higher than about 30%. Percentage parasitism by the parasitic wasp was inversely density dependent on the host densities.