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Cotton fields throughout Mississippi were surveyed prior to or after harvest. Mature weeds that escaped control tactics were recorded from 111 randomly selected fields. In the delta, 66 sites were sampled. Outside the delta, 45 sites were sampled. Weeds between two adjacent rows (76 to 80 inches) were counted for 50 feet (or 100 row feet) at four randomly selected sites in each field. Field borders and skips were not surveyed. Fields adjacent to sampled fields were not surveyed. Goosegrass was the most commonly observed annual grass in the Mississippi delta (Table 1). Bermudagrass and johnsongrass were present in 30 and 21%, respectively, of the fields. Spotted spurge and annual morningglories were present in 45 and 40%, respectively, of the delta fields surveyed (Table 1). Other annual broadleaf weeds frequently encountered were prostrate spurge, prickly sida, cocklebur and hemp sesbania. Several species of perennial vines were present in delta fields. Honeyvine milkweed was present in 30% of the fields surveyed at an average density of 4.7 plants/100 row feet. Redvine and trumpetcreeper were present in 21 and 16%, respectively, of the sampled fields. Populations of these weeds, averaged over the fields in which they were present, were 9.5 redvine and 12 trumpetcreeper plants/100 row feet. Other perennial broadleaf weeds observed were curly dock, horsenettle, and dewberry. Yellow and purple nutsedge were present in 36 and 7%, respectively, of the fields sampled. Goosegrass, crabgrass, and broadleaf signalgrass were the most frequently observed annual grasses outside the Mississippi delta (Table 2). Other grasses were also observed. Barnyardgrass was present in only one sampled field, but, at a density of 100 plants/100 row feet. Bermudagrass and johnsongrass were the most frequently observed perennial grasses. Dallisgrass and vaseygrass were present in 2 fields and 1 field, respectively. Outside the delta, annual morningglories and cocklebur were present in 55 and 48%, respectively, of the fields sampled (Table 2). The average cocklebur density in those fields was 11 plants/100 row feet. Forty-two percent of the broadleaf weeds observed in fields outside the delta were perennial weeds. Trumpetcreeper and dewberry were observed in 35 and 11%, respectively, of the fields surveyed. other perennial vines were observed less frequently. Yellow and purple nutsedge were present in 24 and 6%, respectively, of the fields sampled outside the delta. |
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©National Cotton Council, Memphis TN |
Document last modified Sunday, Dec 6 1998
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