Band applications of herbicides are less common than band applications of insecticides because weeds need to be controlled in the entire field and not just in or on the plant area. Banding herbicides in row crops is not uncommon, however, and has several advantages. The primary advantages are reduced cost and herbicide carryover in the soil. Banding over the crop row is often combined with cultivation. Cultivation is cost effective with immediate gratification. Determining the rate of application when making band applications is sometimes misunderstood and or abused. The application rate should be the same for both band and broadcast applications but the treated acreage will differ depending on the band width. If, for instance, a 50% band is applied on a 10 acre field, 5 acres will be treated. The amount of both water and herbicide should be calculated for 5 acres. This is fairly straight forward but often misunderstood. It can be tempting, when the herbicide is inexpensive and easily accounted for, to apply higher than labeled rates to increase weed control. A good example of this is the use of glyphosate on roundup ready cotton. Although crop safety is well known with this herbicide, there are some instances where other herbicides can cause injury at higher than labeled rates. More important, however, is that this practice increases the possibility of herbicide resistance. Selection pressure for resistant biotypes increases with higher than labeled rates. The rapid increase in the number of glyphosate resistant weeds in the Midwest has been alarming. One of the primary reasons for this has been the progressive increase in application rates to control tough weeds. Increasing rates is a short term solution that can cause long term problems. In addition to increased resistance pressure there can be increased problems with crop and soil contamination with some herbicides.

To contact Barry Tickes go to: btickes@ag.arizona.edu.

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.