What factor is NOT considered part of herbicide formulation?

The selection of pesticide container as a factor not considered part of herbicide formulation is correct because herbicide formulation specifically refers to the composition and physical structure of the herbicide itself. This includes the active ingredients, which are the chemicals responsible for the herbicidal action, surfactants, which enhance the effectiveness of the herbicide by improving its ability to spread and adhere to plant surfaces, and carrier materials, which can help deliver the herbicide to the designated application site.

The pesticide container, while essential for the storage and transport of herbicides, falls under packaging and labeling aspects rather than formulation. The formulation process focuses on the chemical makeup and the physical state of the product that will be applied, rather than the characteristics of the container in which it is stored.