Abstract: The red soil moisture at fruit-swelling stage of Citrus unshiu Marc. cv. Miyagawa Wase was real-time monitored by FDR in 2003〖KG-*2〗-〖KG-*7〗2004 to study the effects of relative soil moisture (RSM) on the fruit growth and yield indices of the citrus. When the RSM increased from 30% to 90%, both the fruit length and the fruit diameter were increasing while the ratio of fruit length to fruit diameter was in adverse, and the weekly accumulative increment of fruit diameter (195〖KG-*2〗-〖KG-*7〗226 cm) was higher than that of fruit length (160〖KG-*2〗-〖KG-*7〗174 cm). The fruit yield index had a parabolic variation trend with the increase of RSM, and reached the maximum when RSM was 75%. After an integrative consideration on the fruit growth and yield index, 75% RSM was suggested to be most beneficial to the fruit growth and high yielding of the citrus.

Key words: Spodoptera litura, Larval instar, Nuclear polydedrosis virus, Disease epizootic, Distribution of disease time, Complementary log log model