Which of the following types of pest control requires a DPR pest control business license?

The correct choice, which highlights the need for a DPR pest control business license, involves the control of tree pests. This is because managing tree pests and diseases often entails implementing treatments that may affect the environment outside residential or industrial settings. Tree pest control can involve the use of pesticides and other regulatory measures that fall under the purview of the Department of Pesticide Regulation (DPR), necessitating a specific license due to the implications on public health and environmental safety.

Preservative treatment of fabrics or structural materials and household or industrial sanitation services do not typically require a DPR business license, as these activities generally do not involve the application of pesticides in a manner regulated by the DPR. Structural pest control, while significant, usually refers to pest management within buildings and may involve different licensing or certification requirements compared to the broad environmental implications of tree pest control, thus leading to a distinction in licensing requirements.