Which of the following pests is associated with citrus plants?

The California red scale is correctly identified as a pest that specifically targets citrus plants. This pest is a type of scale insect that feeds on the sap of citrus trees, which can lead to significant damage and economic losses in citrus production. It can weaken the trees, reduce fruit yield, and compromise the overall health of the plants. Management of this pest typically involves monitoring for infestation and implementing control methods, such as the use of specific insecticides or natural predators.

In contrast, the other pests listed are not specifically associated with citrus plants. The greenbug is primarily a pest of grasses and cereal crops, the armyworm affects a range of crops, particularly those in the vegetable and grain categories, and wireworms are typically associated with root crops and can damage various plants but do not specifically target citrus. Understanding the specific pests that affect different crops is crucial for effective management and control practices.