The USDA organic regulations are written to require farmers to employ tactics to minimize pest and disease problems using a three-level hierarchical approach.
Level A
The first line of defense in managing weed, insect, and disease pests is a systemsbased approach. It is based on the fact that a well-designed and healthy organic system will naturally have fewer pest problems. The system is designed to prevent pest and disease outbreaks.
Level B
The second line of defense is utilized if the practices of level A are not sufficient to control the weed, insect, or disease problem. Level B generally includes mechanical and physical practices that are traditional in organics, as well as the use of nonsynthetic or natural materials.
Level C
The third line of defense is used if the level of pest control required is not achieved after A and B control options are applied. Level C practices include the use of inputs such as biologicals and botanicals to control pests. This level also provides the option of using those materials included on the National List under § 205.601 Synthetic substances allowed for use in organic crop production.
If you anticipate the need for level C control measures, be sure that you indicate this in your Organic System Plan. Be specific about the control materials you might be using and outline the indicators or thresholds you monitor that will trigger the use of those materials.