Abstract: This paper attempts to draw a general relationship between crop yield loss and chewing injury of reproductive organs by insect pests. It is found that there are some common characters of yield response to reproductive organ damage for different crops. At the early stage of reproductive growth,the removal of all or parts of the reproductive organs results frequently in an increased yield. At the late stage, the removal of young organs has little or no negative effect on yield. While at the middle stage, the removal causes a severe yield reduction. Other factors also affect the relationship. Crop yield tends to decrease if large amounts of reproductive organs are damaged,crop variety has a late maturing or determinantly growing property,soil water and nutrient eonditons are relatively bad, cumulated temperature or sunshine are not enough, compensation duration is rather short,plant density is too high or too low,middle stratum organs are damaged,or reproductive organs suffer a follow-up damage. The yield response to reproductive organ loss is similar to that to leaf area loss. This generalized knowledge is needed in improving crop loss assessment and developing IPMprogram for a region planted with different crops.

Key words: Pest-yield relationship, Crops' compensation, Reproductive organ chewing insect, Indirect pest, IPM, leaf senescence, light quality, endogenous hormone