tiny black bugs invade garden sweet corn
There are several insects it could be. The website for Insect Pests of Sweet Corn, https://hgic.clemson.edu/factsheet/insect-pests-of-sweet-corn/ has pictures of some that fit your description, and offers some less toxic suggestions for control such as B.t., spinosad, horticultural oil, neem oil extract, pyrethrins and insecticidal soap.
More toxic insecticides are also listed, and days between spraying and harvesting are noted on this website. Read and follow carefully all instructions and precautions on the product labels before applying. These insecticides may affect bee populations.