Corn Leaf Aphid
Rhopalosiphum maidis (Fitch)

These aphids are greenish-blue and about 2 mm long. Their cornicles, legs, and antennae are black, and they have a dark spot on the abdomen at the base of their cornicles. They suck sap from plants and can vector barley yellow dwarf virus. Host plants: cereals, corn, grasses.