Which pest is known to affect avocados by causing damage as a mite?

Oligonychus perseae, commonly known as the avocado mite, specifically impacts avocado trees by feeding on their foliage. This pest causes damage by puncturing the plant's cells with its mouthparts and sucking out the cell contents, which leads to stippling, yellowing of leaves, and potential defoliation. The avocado mite is particularly concerning because it can reduce photosynthesis, weaken the tree, and make it more susceptible to other stresses or diseases.

In contrast, the other options do not affect avocados in this manner. Rhagoletis completa refers to the apple maggot, which primarily targets apple trees, while Cydia pomonella, known as the codling moth, commonly infests apple and pear crops. Agrobacterium tumefaciens is a bacterial pathogen responsible for crown gall disease in various plants, which is unrelated to mite damage. Therefore, selecting Oligonychus perseae highlights an understanding of pest identification and their specific impact on avocado crops.