Difficulties in detecting stink bugs in cotton prompted us to focus on using their damage to bolls as a monitoring tool for treatment decisions. In field-cage studies designed to follow the development of boll-injury symptoms caused by stink bugs in individual boll cages, significant numbers of internal feeding punctures were observed in bolls after 24 h of exposure to 5th instars of southern green stink bug, Nezara viridula (L.). However, 48 h were required for significant development of external symptoms and internal, wart-like growth complexes. In additional cage tests to investigate damage caused by stink bugs, 5th instars of N. viridula caused more internal boll damage than adults and younger nymphs, and damage decreased as boll age increased from 4-21 d from white bloom; damage at and after 18 d was negligible. In small field plots testing the effectiveness of using levels of boll damage for management of stink bugs, stink bugs caused light damage to bolls, and treatment with insecticide at different levels of internal damage minimally affected damage and yield.