Corn Injury Symptoms Part 3. Synthetic Auxin Effects on Corn Part 4. Synthetic auxin herbicides can be absorbed by roots and above-ground plant parts and move readily throughout the plant. Synthetic auxin herbicides are not strongly adsorbed to the soil and have medium to high leaching potential that varies with soil type. These herbicides are also volatile which requires care to prevent off-target plant injury.
Synthetic auxin herbicides primarily control annual and perennial broadleaf weeds.
They are active when applied to the soil or foliage, but are primarily used postemergence. The most common visual symptoms of synthetic auxin herbicide injury are epinastic growth, such as twisting, cupping, and curling. Other common symptoms include gall-like growth, stimulation of secondary root growth, inhibition of root and stem development and fasciation of roots, stems and leaves. The growth regulator-type herbicides are the oldest class of synthetic organic herbicides. The Herbicide Resistance Action Committee and the Weed Science Society of America classify four herbicide families in the 'synthetic auxin' group.