What type of scale insects remain securely fastened to the plant surface?

Mature scale insects are known for remaining securely fastened to the surface of the plant. As they develop, they settle in one location and establish a feeding site, which is critical for their lifecycle. This attachment allows them to maintain a stable feeding position from which they can extract sap from the host plant, often without moving to seek new locations for nourishment.

This sedentary lifestyle is a significant characteristic of mature scales, distinguishing them from immature scales, which are typically more mobile as they search for a suitable place to establish themselves. Winged scale insects, while they exist in some life stages, would not be relevant here since they do not remain fastened to a plant's surface. The term "infected scale" is not a recognized category within the context of scale insect classification. The focus here is on the lifecycle stage where the scale insect has fully matured and has adopted a stationary feeding strategy on the host plant.