The movement of crop protection materials away from their intended target, otherwise known as “drift,” poses several potential problems. For farmers who use herbicides, the consequences of drift are wasted production inputs and less effective weed control, which lead to higher production costs and lower crop yields. Drift can also pose other problems for herbicide-applicators, including legal complications that may occur if the drift from a chemical application causes damage to other people or their property.
For producers who grow herbicide-sensitive crops, such as grapes and vegetables, herbicide injury can cause significant or complete financial loss from lost crop production. Most herbicide-sensitive specialty crops require intensive management and have the potential to produce high revenue per acre; this fact intensifies growers concern regarding injury caused by herbicide drift.
In order to avoid potential financial loss, conflict, and legal complications that arise from herbicide drift, both herbicide applicators and specialty crop growers should take preventive action. For herbicide applicators, drift-prevention includes having an acute awareness of environmental conditions at the location and time of application. Applicators should be aware of herbicide-sensitive crops growing near the treatment area. They should also be cognizant of wind speed, wind direction, temperature, and relative humidity, which affect the occurrence and extent of drift.
Furthermore, applicators should be conscious of their spray equipment. Boom-height, nozzle type, spray angle, volume, pressure, and groundspeed all play a role in reducing drift. The label of the herbicide product provides guidance on sprayer calibration. Additionally, the MU Extension guide, “Controlling Drift of Crop Protection Materials,” is a great reference for applicators regarding drift. The guide is available online or at your local MU Extension Center.
The most important step growers can take is to communicate with neighboring farmers, custom-applicators, and county roadside spray crews who service the area. More information on herbicide selection, herbicide injury, and recommendations for preventing drift problems is available by contacting your local MU Extension office.