Weed Control and Population Dynamics in Early Vs. Late Season Maturing Cotton

C.T. Bryson


 
ABSTRACT

Field experiments were conducted in 1985-1986 at Mississippi State, MS to evaluate the weed control and population dynamics following two cotton (Gossypium hirsutum L.) cultivars, 'Stoneville-213' and 'CAMD-E', with and without herbicide treatments. Herbicide treatments included: Treflan, Prowl, and Basalin at 0.5 and 1.0 lb/A applied preplant incorporated (ppi); Cotoran at 0.8 and 1.6 lb/A, Zorial at 1.0 and 2.0 lb/A, and MSMA at 3.0 and 6.0 lb/A applied preemergence (pre); Treflan at 0.5 lb/A (ppi) + Zorial at 0.5 lb/A (pre) + MSMA at 3.0 lb/A (pre); and Treflan at 0.5 lb/A (ppr) + Cotoran at 0.8 lb/A (pre) + MSMA at 3.0 lb/A (pre). In 1985, canopy shading by 'CAMD-E' was of shorter duration than 'Stoneville 213' and resulted in increased weed seed germination, growth, and seed production from the preceding year. There were more weeds (plants/A) in cotton in 1986 in plots that had been planted to 'CAMD-E' the preceding year than in plots planted to 'Stoneville 213'. The number of crabgrass (Digitaria sp.), goosegrass [Eleusine indica (l.) Gairtn.] Nash], pigweed (Amaranthus sp.), spurge in 1986 by 2.4-,1.7-, 13.8-, 2.6-, 5.5-, and 2.9-fold, respectively, following 'CAMD-E' vs. Stoneville 213' in the herbicide-free plots. In the herbicide-treated plots, the differences in weed population (plants/A) between 'CAMD-E' and 'Stoneville 213' the following year (1986) was similar to the herbicide-free plots at crop and weed emergence, but weed population were lower in all species except nutsedges. When averaged over all herbicide treatments and compared to the herbicide-free treatments, weed control was greater in 'Stoneville 213' plots (87 and 72%) than in 'CAMD-E' plots (50 and 69%) at harvest in 1985 and in early summer (June 4) 1986, respectively. With an increased emphasis on reduced tillage and herbicide use, weed control problems may increase in early maturing cotton varieties especially following a warm, wet fall where weed seed and propagules of perennial weed population increase. More research is needed to investigate control and population dynamics of weeds in additional early maturing cotton cultivars.



Reprinted from 1990 Proceedings: Beltwide Cotton Production Research Conferences pg. 346
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998