There are many different species, but flea beetle adults are small (about 0.125 inch or 1 mm long), shiny, hard beetles with enlarged hind legs that allow them to jump like fleas when disturbed. Different species vary in color and markings.
Adults do most of the damage by feeding on leaves, creating holes. Most serious damage is done when plants are seedlings; older plants are more tolerant although outer leaves can show damage.
They appear most commonly in spring but can occur any time, especially in weeds in or near the garden. To help control, remove weeds and debris in and near the garden. Seedlings can be protected with row covers. Sticky traps can be used to help monitor the populations. Insecticides are not very effective.
Read more about flea beetles.
Leafminer adults are small black and yellow flies. Larvae are yellowish maggots that feed beneath the leaf surface leaving tunnels.
Read more about leafminers in the vegetable garden.