Which pest is commonly associated with corn, known scientifically as Rhopalosiphum maidis?

The pest scientifically known as Rhopalosiphum maidis is the Corn Leaf Aphid, making it the correct answer. This aphid is particularly notable for its association with corn crops, where it feeds on the sap of the leaves. Its presence can lead to the yellowing of leaves, stunted growth, and reduced yields due to the plant's accumulation of stress from feeding and potential vectoring of diseases such as corn viruses.

In contrast to the Corn Leaf Aphid, the other options represent different pests that affect various crops. The Pink Bollworm targets cotton plants, while Helicoverpa zea, also known as the corn earworm, can indeed affect corn but is a distinct species from the aphid in question. Tetranychus pacificus, commonly known as the Pacific Spider Mite, affects a range of host plants including various fruits and vegetables, but is not specifically associated with corn. Understanding these distinctions is crucial for effective pest management and intervention strategies in agricultural practices.