Clomazone, Fomesafen, and Bromoxynil Systems for Bromoxynil-Resistant Cotton (Gossypium hirsutum)1

Abstract

Studies were conducted at Clayton, Lewiston, and Rocky Mount, NC, to evaluate weed and cotton response to herbicide systems in bromoxynil-resistant Stoneville BXN 47 cotton. Herbicide systems that included clomazone preemergence (PRE) controlled broadleaf signalgrass, common lambsquarters, common ragweed, goosegrass, large crabgrass, and prickly sida greater than 88%. Inconsistent Palmer amaranth control was observed with the addition of fomesafen PRE to clomazone PRE and pendimethalin preplant-incorporated (PPI) herbicide systems. Addition of bromoxynil early postemergence (EPOST) to clomazone and pendimethalin systems increased ivyleaf morningglory control to greater than 84% and provided higher yields than did the same systems without bromoxynil. Bromoxynil EPOST followed by (fb) cyanazine MSMA late postemergence directed (LAYBY) improved weed control in clomazone and pendimethalin systems. Clomazone PRE and pendimethalin PPI with or without fomesafen PRE fb bromoxynil EPOST fb LAYBY herbicides controlled weeds and yielded equivalent to the standard herbicide system of pendimethalin PPI fb fluometuron PRE fb bromoxynil EPOST fb LAYBY.Nomenclature: Bromoxynil; clomazone; cyanazine; fluometuron; fomesafen; MSMA; pendimethalin; broadleaf signalgrass, Brachiaria platyphylla (Griseb) Nash. #3 BRAPP; common lambsquarters, Chenopodium album L. # CHEAL; common ragweed, Ambrosia artemisiifolia L. # AMBEL; goosegrass, Eleusine indica (L.) Gaertn. # ELEIN; ivyleaf morningglory, Ipomoea hederacea (L.) Jacq. # IPOHE; large crabgrass, Digitaria sanguinalis L. # DIGSA; Palmer amaranth, Amaranthus palmeri S. Wats. # AMAPA; prickly sida, Sida spinosa L. # SIDSP; cotton, Gossypium hirsutum L. ‘Stoneville BXN 47’.Additional index words: Herbicide-tolerant crops.Abbreviations: EPOST, early postemergence; fb, followed by; LAYBY, late postemergence directed; PD, postemergence directed; POST, postemergence; PPI, preplant incorporated; PRE, preemergence.