Herbicide combinations for the control of weeds in cotton

In order to determine the effect of several herbicide combinations against weeds in cotton (Gossypium hirsutum var. latifolium L.) fields a trial was placed at Surubim, PE, Brazil, in 1978. None of the treatments caused deleterious effects to cotton plant. The residual herbicides were slightly more efficient controlling weeds when applied in pre-emergence state as compared to pre-sowing incorporation. The more efficient mixtures, which allowed higher cotton fields, were: alachlor 3,0 l/ha (pre-emergent) + diuron 1,0 kg/ha (pre-emergent); penoxalin 3,0 l/ha (pre-emergent) + diuron 1,0 kg/ha (pre-emergent) and trifluralin 1,5 l/ha (pre-sowing incorporated) + fluometuron 1,5 kg/ha (pre-emergent). The predominant weeds were: Malvastrum coromandelianum (L.) Gurcke, Ageratum conyzoides L., Boerhavia decumbens L., Alternathera ficoidea L, Galinsoga parviflora Cav., Ipomoea sp., Achanthorpermum hispidum DC., Hyptis capitata Jacq., Desmodium tortuosum (Swartz) DC., Cenchrus echinatus L., Paspalum sp., Cyperus sp.