A color-based imaging system and method for the detection and classification of insects and other arthropods are described, including devices for counting arthropods and providing taxonomic capabilities useful for pest-management. Some embodiments include an image sensor (for example, a digital color camera, scanner or a video camera) with optional illumination that communicates with a computer system. Some embodiments include a color scanner connected to a computer. Sampled arthropods are put on a scanner to be counted and identified. The computer captures images from the scanner, adjusts scanner settings, and processes the acquired images to detect and identify the arthropods. Other embodiments include a trapping device and a digital camera connected by cable or wireless communications to the computer. Some devices include a processor to do the detection and identification in the field, or the field system can send the images to a centralized host computer for detection and identification.