Defoliation of cotton plants by applying phenylsulphonyl-urea derivs. - and new defoliant compsn. these derivs. and n-phenyl-tetra:hydro:phthalimide synergist

摘要

Cotton plants are defoliated by applying phenylsulphonylurea derivs. (Ia) and (Ib) or alkali(ne earth) metal salts. R1 = 1-4C alkyl or 3-5C alkoxyalkyl opt. mono-, di- or trisubstd. by halogen; 3-4C alkenyl; or 3-4C alkynyl; R2 = fluorine, chlorine or bromine; R2' = H, fluorine, chlorine or bromine; R3 = H or (m)ethyl; R4 = halogen, methyl or methoxy; R5 = methyl or methoxy; R6 = 1-2C alkyl, 1-2C alkoxy, 1-2C alkylthio or 1-2C alkylamino; Z = CH or N. USE/ADVANTAGE - New method is used in cotton reaping, with low amts. of cpds. (Ia) and (Ib), e.g. 0.1 g- 3kg/ha, being applied. New method is better than known defoliation methods in that higher quality fibre is obtd. and re-shotting occurs only to an insignificant extent. Also new compsns. are more effective than compsns. contg. the cpds. described in DE3413565 and US 4127405.