Four defoliants were tested, alone and blended at different rates on cotton cv. IAC 13-1 on clay soil of Ipiaçu-MG. The treatments consisted of 0,71 and 1,42 kg i.a./ha of folex (71,2% of tributyl phosphorotrithioate), 1,06 and 1,41 kg i.a./ha of def (70,5% of s,s,s, - tributyl phosphorotrithioate), 0,36 and 0,54 kg i.a./ha of paraquat (36,2% of 1'1 dime thyl-4-4'- bipyridyldiylium ion), 1,92 kg i.a./ha of ethrel (48% of chlorethyphosphoric acid), paraquat + def (0,36 + 0,70 kg i.a./ha), paraquat + folex (0,36 + 0,70 kg La./ha), paraquat + folex (0,54 + 1,42 kg i.a./ha), paraquat + def (0,54 + 1,41 kg i.a./ha), paraquat (0,36 and 0,54 kg i.a./ha) and a check. Each treatment was repeated four times. Spray were done when 70% to 80% bolls were open using 800 1 of water/ha. Data were taken from the number of dried + green leaves and the effect of defoliants weeds by the E.W.R.C. scale. Def (1,41 kg i.a./ha), paraquat + folex (0,54 + 1,42 kg i.a./ha) and paraquat + def (0,54 + 1,41 kg i.a./ ha) were the best treatments 5 days after spraying. New growth induced by rains equalized all treatments, except the check, 10 days after the application and including the 5 days later. Paraquat alone or blended, was the best product to control weeds making easier the mechanical harvester work and improving the raw-cotton quality.
Defoliants; herbicides; cotton; weeds