Abstract: The fluorescent substance tracing method was used to quantitatively measure and analyze the damage to rice plants by the white-backed planthopper Sogatella furcifera and the ability of the lycosid spider Pirata subpiraticus to control Sogatella furcifera during the two rice growth stages (the tasseling and maturing stage).The results show that the fluorescent substance content of the rice plant, Sogatella furcifera and Pirata subpiraticus obviously increased with increasing concentration of fluorescent substance from 20 mg/L to 50 mg/L to 100 mg/L respectively. During the tasseling stage, rice consumption by Sogatella furcifera was 0.0636 g per insect every 24 h, and the consumption of Sogatella furcifera by Pirata subpiraticus was 0.0336 g per spider every 24 h, equaling 6-7 planthoppers per day. During the maturing stage, rice consumption of Sogatella furcifera was 0.0115 g per insect every 24 h, and the consumption of Sogatella furcifera by Pirata subpiraticus was 0.0416 g per spider every 24 h, equaling 16 planthoppers per day. Comparing the two growth stages, the per gram fluorescent substance content of Sogatella furcifera and Pirata subpiraticus was significantly higher at the maturing stage than at the tasseling stage.

Key words: Sogatella furcifera, Pirata subpiraticus, fluorescent substance, biomass flow, quantitative analysis