Herbicide injury: Leaf lesions
Disorder
Symptoms
Multiple spots can result in deformed leaves as well as leaf curling. Systemic herbicides, those that are translocated in the plant, tend to cause a yellowing of the foliage.
Causes
Generally, foliar damage occurs when herbicides are applied at excessive rates, at the wrong stage of plant growth or during unfavorable weather conditions. Injury often occurs from herbicide drift when crops or weeds adjacent to onions are sprayed. Damage from drift is usually most severe at the edge of a field closest to where a herbicide was applied, with injury decreasing with increasing distance from the source.
Control
Use herbicides as directed and apply during appropriate weather conditions. Plants will frequently recover from foliar damage if it is not too extensive.