Tobacco pests include diseases, insects, nematodes, and weeds. Each of these pest groups are managed differently. For most tobacco insect pests, management is based on thresholds, which typically entails tolerance of some insects in a planting. Disease management is often preventative, but depending upon the disease, may also be in response to infection. Weed management utilizes both pre and post emergence materials and is therefore, either preventative or responsive, respectively.