What is the risk over overspray from herbicide application?
The use of herbicides to control weeds and invasive plants is fairly common, but should only be done as part of an overall program of roadside control of vegetation. Anyone spraying should be trained in the proper application of any chemicals.
The figures show the damage to an alfalfa crop by overspray. It has effectively killed the alfalfa; there is no regrowth coming in what should have been a second cutting. The farmer decided to dispose of the forage from the treated area to protect his animals and other crops. Residue from some herbicides can pass through animal manure and affect susceptible crops when the manure is spread.
In this case, the applier was not sure of what is a crop and what is a weed (what should be sprayed and not sprayed). Training may have saved this crop.
- Can you identify farm crops vs roadside plants?
- Is the area an actively farmed field versus an unfarmed roadside?
(In the case in the photos below, the farmer was farming right out to the edge of the road, hence there would be no weedy overgrowth occurring and no need to spray. Whether the farmer should have been planting up to the roadside is an issue of right-of-way and safety and is the subject of a different Quick Answers).
- Can you identify the difference between broadleaf and grass hay crops?
- Do you understand that if you apply broadleaf herbicides, it will kill broadleaf crops as well?
Resources:
Pesticide Safety Education Program (PSEP) Part of the Cornell Pesticide Management Education Program
http://psep.cce.cornell.edu/
