Xue, J.L., Xie, Y.P., Fan, S.H., & Li, Y.F. 2004 A study on the nutriology promoting the population increase of Eulecanium gigantea by urban pollution.. Scientia Silvae Sinicae 40(1): 110-116.

Notes: A study was conducted during 1998-99 on five areas with different degrees of air pollution in Taiyuan City and a clean area in Shanxi Agricultural University located in Taigu County, Shanxi Province, China, to investigate the nutriological relationship between the soft scale (Eulecanium gigantea) population increase and its host plant, Sophora japonica [Styphnolobium japonicum]. Results showed that in the polluted areas, the quantity of reductive sugar, general sugar, soluble protein and amino acids in twigs and leaves of the host tree were much higher than those in the clean area. The soft scale population density increased as the air pollution worsened. The contents of reductive sugar and soluble protein in twigs were positively and significantly correlated to the population density of the soft scale insect. During March and October, the trend of the nutrient content in the twigs of the host tree showed two peaks and a valley, which represents two feeding stages and an egg stage of the soft scale in its life cycle. It is suggested that the high nutrient content of the host tree in the polluted urban environment may be one of the factors affecting the population increase of soft scale insect.