Which of the following is NOT a sap feeder?

The black cutworm is identified as not being a sap feeder because its feeding habits involve cutting through and damaging plant stems or leaves rather than extracting sap. Black cutworms are actually classified as cutworms, which are the larval stage of certain moths. They typically engage in feeding on foliage and can cause significant injury to young plants by cutting them off at the base.

In contrast, the other pests listed, such as the green peach aphid, leafhopper, and scale insect, are all known for their sap-feeding behavior. They utilize specialized mouthparts to pierce plant tissues, allowing them to extract nutrient-rich sap, which can weaken plants, lead to stunted growth, and even cause the transmission of plant diseases. Understanding the differences in feeding mechanisms is crucial for effectively managing these pests and protecting crops.