The pre-bloom period of fruiting is an important period in cotton production. The loss of pre-bloom squares may cause serious yield losses if square loss is allowed to continue for a period of time. Square loss may be due to physiological stress or physical injury. Physiological shed may be attributed to either biotic or abiotic factors. Abiotic factors that contribute to square shed include moisture, nutrients, cultivation, stress from the general feeding of insects or nematodes. Aphid and thrips may be present in large numbers and the feeding pressure great enough to result in a type of physiological stress that causes square shed similar to moisture stress. Square loss as the result of physical injury from feeding by insects include plant bugs, lepidopterous larvae, and boll weevil. The plant bug is the primary cause of early season square shed and squares usually shed within 1 to 4 days after being feed upon by plant bugs species.

The monitoring of square set and diagnosis of the cause of square shed is necessary for early season management of the cotton crop. The newest approach to management of square set is the use of plant mapping procedures that identify square shed by nodes. Furthermore, field diagnosis procedures have been developed that allow consultants and scouts to identify quickly the cause of square shed.