Which of these is NOT considered an ornamental insect?

Quackgrass is classified as a weed rather than an ornamental insect. It does not belong to the category of insects typically associated with ornamental plants. Insects like spider mites, holly leafminers, and rose chafers are known to interact with ornamental plants; they can cause damage, affect plant health, and are often targeted for pest management practices in ornamental horticulture.

Spider mites are small arachnids that can infest many ornamental plants, leading to discoloration and leaf damage. Holly leafminers are larvae that specifically target holly plants and can create noticeable damage to the leaves. Rose chafers are beetles that are known to feed on the foliage and flowers of roses and can be detrimental to the health and aesthetics of these ornamental plants. Understanding these distinctions is crucial for effective pest management in ornamental horticulture.