Aphids, thrips, mites, leaf miners
» Can be found on the surface of the leaves or in the inner leaves
Napa cabbage is commonly used in Chinese restaurants and requires a comprehensive method of cleaning and checking. Some Napa cabbage stems can have black dots that appear to be insects. The simplest way to differentiate between an insect and a black dot in the fiber of the stem is to use your nail to gently scrape on the black spot. If it does not come off, you can be assured it is part of the vegetable.
The same steps for washing and checking romaine lettuce should be followed for Napa cabbage and other Chinese greens