Which class of insecticide is known for controlling sucking insects and is systemic in action?

The correct response identifies neonicotinoid insecticides as the class that is effective in controlling sucking insects and operates systemically. Neonicotinoids are a type of insecticide that affects the central nervous system of insects, leading to paralysis and death. These chemicals are particularly effective against insects like aphids, whiteflies, and thrips, which feed by sucking sap from plants.

The systemic nature of neonicotinoids means that they can be absorbed by plants and translocated throughout their tissues. This allows them to provide protective effects not just at the site of application but throughout the entire plant, making them particularly advantageous for controlling sucking insects that might feed on various parts of the plant. This characteristic is crucial, as it helps ensure that even insects hidden within the plant or feeding on newly grown tissues can be effectively controlled.

Other options such as nematicides are primarily used for controlling nematodes, which are different in nature and do not target sucking insects. Pathogens refer to disease-causing agents, and while some can control plant pests, they do not function as insecticides. Parasites might play a role in biological control but are not classified as insecticides, nor do they have a systemic mode of action like neonicot