Sounds like you may have Aphids.
There are a lot of home remedies to get rid of them, such as: Take 1 cup of vegetable oil (or mineral oil), 1 and 1/2 cups of water, and 2 teaspoons of dish soap and combine in a spray bottle; spray onto aphids and apply for several days.
There are also insecticides but I'd try my best to stay away from those, especially with food related items; I like trying to keep everything as organic as possible...