A tankmix of the two can be made and sprayed successfully, but the time of incorporating is necessarily a compromise. Glyphosate needs to be absorbed and translocated through a plant to provide good control. Tissue affected by Spray. Seed, but only to provide control of weeds upon which the Spray. Seed has little effect, such as clovers or melons.
Some herbicides reduce the activity of others.
This is known as antagonism . Antagonistic herbicides must not be mixed, and also they must not be applied as sequential sprays. MCPA alters the metabolism of ryegrass and wild oats in such a way that these grasses no longer respond to diclofop, even though MCPA is not itself toxic to them. The chemicals must be applied at least 10 days apart. Bromoxynil reduces this antagonism.