Answer: Pansies are usually quite trouble free, so unless you actually notice a problem you shouldn't worry too much. In my experience the most common problem would be aphids, which are little tiny soft-bodied sucking insects which you would find on the newest growth of the plant. These can be washed off with a spray of the hose or treated with insecticidal soap according to the label instructions. Another pest you might find is whitefly; whiteflies generally appear in groups and are so small that they go unnoticed until the plant is disturbed and they fly up all at once. These will freeze to death once the weather gets cold, but can also be treated the same as aphids.
Healthy plants tend not to suffer many insect or disease problems, so try to keep your pansies healthy. Pansies grow best in cool weather and naturally tend to look shabby (or simply die altogether) when the weather turns hot. For best results, plant them in a rich, moist but well drained (meaning not soggy) soil well enriched with plenty of organic matter. Mulch around them but not over them and for increased bloom, remove flowers as they fade.
Enjoy your pansies!
Q&A Library Searching Tips