Cotton fields in three southeast Missouri counties representing over 90% of the cotton growing area of Missouri were surveyed. Five fields in each county were randomly chosen and surveyed for uncontrolled, mature weeds. The survey technique consisted of counting mature weeds in 30 feet of row between two 38 inch rows at five locations in each field. Data were converted to number of weeds per 100 row feet for reporting purposes. Some fields were hand-hoed in addition to other weed control practices. The five most abundant weeds in the survey across counties were 1) prostrate spurge, 2) prickly sida (teaweed), 3) pitted morningglory, and 4) trumpetcreeper. This is somewhat misleading because prostrate spurge ranked 13th in frequency of occurrence (number in parenthesis in table). In contrast, pitted morningglory, trumpetcreeper, and prickly sida ranked first, third, and sixth, respectively, in frequency of occurrence. Although common cocklebur was eighth in most abundant, it ranked second in frequency of occurrence.

The following weeds were observed in the surveyed fields, however, were not encountered in the counted areas: bermudagrass, eclipta, hemp sesbania, hophornbeam copperleaf, puncturevine, jimsonweed, purslane, giant ragweed, smartweed, southern pea, toothed spurge, and velvetleaf.