Aphids

These appear to be common sap-sucking insect pests (found on many plants) called Aphids. They are pretty easy to control. The females reproduce live young (minatures of themselves) in multiple numbers, and without being fertilized by a male, so they can reproduce quickly in the right environment. As they suck out the sugary plant sap they also excrete it, which makes the leaves sticky. We recommend you control this population as soon as possible by either spraying off with a high pressure spray of water, picking off the most infested leaves, and when new populations are found clean/wipe them off by hand, and continuing to do so until they stop showing up. You can also use a product like pesticidal soaps or an horticultural oil. Be careful to follow the directions on all product labels. (The oil in particular can cause plant damage if applied incorrectly/under the wrong temp and moisture conditions). We’ve included a link with more info about Aphids and ways to control them.
http://www.ipm.ucdavis.edu/QT/aphidscard.html