In 1999, the Mid-South region of the United States Cotton Belt experienced low yields despite minor insect problems. Very hot, dry weather during boll development led to low levels of carbohydrates for satisfactory plant metabolism. Resultant smaller boll sizes and shorter staple length were responsible for the low yields. The experience of Arkansas during 1999 illustrates the problems that the entire region encountered. In Arkansas, the average yield was 715 pounds of lint per acre compared with an average of 756 pounds of lint per acre for the last five years. Boll numbers per acre were high, boll weight was low, and seed number per boll was normal. Fiber quality was generally good. The major pests were bollworms and boll weevils. The crop development pattern showed good early season growth with satisfactory root growth, good early season growth with satisfactory root growth, good seedling and canopy development, and excellent square set and retention. However, during the first fiber weeks of flowering and boll development, temperatures were very high and rainfall was extremely low, resulting in low boll weight and knotty bolls. Abstract.