Which of the following describes the action of lace bugs on plants?

Lace bugs are sap-sucking insects that primarily target the undersides of leaves. They feed on plant sap, which leads to distinctive symptoms on the foliage. One of the most noticeable effects of their feeding is the development of yellow splotching on the upper leaf surface. This yellowing occurs because the insect removes the chlorophyll, causing that portion of the leaf to lose its green color. In addition to this discoloration, lace bugs also excrete waste that appears as small dark spots on the leaf surface; these spots are a result of the excrement being deposited on the plant as they feed.

In contrast, while chewing insects cause physical damage by creating holes in leaves, lace bugs do not have this feeding behavior. Similarly, webbing is produced by different pests, such as spider mites, and is not associated with lace bugs. Furthermore, while leaf drop and wilting can occur due to various stress factors, lace bugs specifically do not cause these symptoms as a direct result of their feeding behavior. Thus, the identification of yellow splotching and excrement spots distinctly characterizes the action of lace bugs on plants.