Abstract: 【Aim】 This study aims to identify the effects of the secondary plant substances, phenolics, on the gypsy moth, Lymantria dispar (L.), and to establish the theoretical foundation to control pests using these phenolics. 【Methods】 We chose four kinds of phenolic acids (salicylic acid, syringic acid, chlorogenic acid and tannic acid), which were mixed in artificial diet separately, to test the influence of phenolics on the growth and development and fecundity of the 2nd instar larvae of L. dispar. 【Results】 The results showed that different phenolic acids had different influences on L. dispar larvae. Tannic acid caused the larval mortality of 22.2% on the 12th day after feeding, which was significantly higher than the mortality in the control (larvae fed on normal artificial diet) (3.3%) (P＜0.01) and treatments with other phenolic acids. The larval mortalities caused by tannic acid and chlorogenic acid increased straightly from the 22nd day and reached 100% on the 34th day after feeding. Both tannic acid and chlorogenic acid reduced the larval weight and prolonged the developmental duration, frequently causing incomplete ecdysis, even all died, at the 4th instar larval stage. The larvae fed on the diet containing salicylic acid or syringic acid pupated and grew to adults, and the pupal weight of females increased significantly but the number of eggs laid per female and fertilization rates of eggs decreased obviously. Compared with the control, syringic acid caused a decrease of 90 eggs in the number of eggs laid per female, a 35% decrease in the fertilization rate of eggs, and also a reduction in the proportion of female adults. 【Conclusion】 The results suggest that different phenolic acids accumulated in pests would result in various degrees of influence on the growth and development and fecundity of the pest.

Key words:  Lymantria dispar, secondary plant substances, phenolics, phenolic acids, growth and development, fecundity