The influence of 4 levels of depodding (0, ⅓, ⅔, and 3/3) at 4 levels of defoliation (0, ⅓, ⅔, and 3/3) on yield of soybeans was evaluated at each of 5 stages of growth (R6, R7, RS, R9, and R10). Defoliation of ⅓ at R6 did not significantly reduce yields at any level of pod removal. As at R6, defoliation of ⅓ at R7 did not significantly reduce yields, but depodding of ⅓ did. At both R8 and R9, both defoliation and depodding of ⅓ significantly reduced yields. Defoliation at R10 did not cause significant reductions at any level, but depodding of ⅓ significantly reduced yields. Multiple regression techniques were used to develop equations for yield reduction at each growth stage as functions of defoliation and depodding. The equation with the best fit at R6 consisted of defoliation only, whereas the equations with the best fit at the other 4 growth stages contained defoliation, depodding, and the interaction term. Based on average leaf area for each growth stage and average leaf area consumed in their development, economic injury levels were calculated for 7 insect pests of soybeans. These injury levels varied both between species and growth stages.