Abstract: 【Aim】 In recent years Apolygus lucorum (Meyer-Dür) damage to cotton has become the hot topics and research focus. To more deeply understand the damage characteristics of this pest to different growth stages of cotton, quantify the damage, and provide the basis for early forecasting of damage, we examined the relationship of early damage characteristics at different cotton growth stages and late bolls. 【Methods】 The damage characteristics of A. lucorum to different growth stages of cotton were investigated with artificial pest infection method in the field. 【Results】 Piercingsucking damage for 24 h by A. lucorum at the cotton cotyledon stage and 2-leaf stage could cause headless plants, while no headless plants were observed after 2-leaf stage. Regression model of the rate of headless seedlings with the damage degree of cotton growing point (y=0.1906x-0.0439, 1≤x≤5), and regression models of the damaged leaf index with the damage degree of cotton growing point and the number of piercing points at 4-leaf stage (y=0.532+0.202x₁+0.005x₂, 0≤x₁≤5, 1≤x₂≤5), 6-leaf stage (y=-0.063+0.339x1+0.002x2, 0≤x₁≤5, 1≤x₂≤5) and 8-leaf stage (y=-0.150+0.087x₁+0.001x2, 0≤x₁≤5, 1≤x₂≤5) were built respectively. Damage of A. lucorum to cotton at the budding and flowering stages had no significant effects on the abscission rates and sizes of late bolls. Damage of A. lucorum to the young cotton bolls with diameter less than 10 mm and 15 mm caused the corrected abscission rates of 55.0% and 26.6%, respectively, while the abscission rates of bolls with more than 15 mm diameter were 0. Sizes of mature bolls were not significantly influenced by A. lucorum damage. Regression models of the abscission rates of cotton bolls with 10 mm diameter (y=0.1857x-0.081, 1≤x≤5) and 10-15 mm diameter (y=0.0522x-0.0068, 1≤x≤5) with piercing points were built respectively. 【Conclusion】 The results indicate that cotton at the cotyledon stage, 2-leaf stage and young boll stage are very sensitive to the damage of A. lucorum. The regression model of piercing-sucking damage could be used in short-term forecasting for damage loss of A. lucorum. Key periods of cotton plants sensitive to damage of A. lucorum should be selected to promote the control efficiency.

Key words: Apolygus lucorum, cotton, pest inoculation test, number of piercing points, damaged leaf index, headless seeding rate, abscission rate