Herbicides Cell Membrane Disruptors
Symptoms depend on the herbicide used, application time and the dosage. Generally, leaves exhibit water-soaked lesions, which later dry up. Burning of tissue or failed emergence are characteristic of these herbicides when applied pre-emergence. When applied post-emergence, they can cause burning in a speckled pattern. It can be confused with paraquat injury but has, in turn, no bronze coloration.
The damage is caused by herbicides of the PPO inhibitors, among other Flumioxazin, Fomesafen, Lactofen, Carfentrazone, Acifluorfen, belonging to the diphenyl ether family. They disrupt the cell membrane among other things by blocking the production of chlorophyll. Leaf symptoms appear within 1-3 days, depending on light and weather conditions. The symptoms are triggered by light and worsen on bright, warm days.
There is no biological treatment available for this condition. Prevention and good farming practices are the keys to avoiding the harm that happens in the first place. Wash and rinse plants thoroughly in the case of suspected overdosage.
Always consider an integrated approach with preventive measures and biological treatments, if available. Before planning a herbicide spray, be sure that you know the type of weed you are dealing with (basically broadleaf weeds vs grasses) and choose the best method available. Carefully select the herbicide and follow dosage instructions as indicated on the label.