What makes this statement by John Palumbo so popular is that it is so true. Weeds, like insects, can be unevenly distributed across fields. There is just no substitute for walking the field. Many are difficult to see and hidden in cracks in the soil or under the crop. Some look very similar to the crop. Most weeds are more easily controlled when less than a quarter inch in size and can grow to this stage in a couple days. Unlike insects and diseases, weeds are more visible when they get big and just a few weeds per acre can be unsightly and destroy a growers reputation for having clean fields which is important in the vegetable business. An infestation of 10 weeds per ft2 is heavy but not uncommon. Even a highly effective herbicide that produces 99% control will leave 1 weed /10 ft2. This will not reduce crop yield or quality but it is unsightly and generally unacceptable.

When in Doubt Scout

Tickes/J.Pena

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.