Herbs are susceptible to common pests, including whiteflies, spider mites, aphids, mealybugs, scale insects, and thrips. Inspect herbs regularly.

If your herbs are in portable containers, control pests by dipping the whole aboveground part of the plant into a pail of insecticidal soap. Swish vigorously for a minute or two to wet all leaf surfaces (hold your hand over the pot to prevent soil loss). Dipping once or twice a week for three to four weeks will clear up most problems.

Photograph by Suzanne DeJohn/National Gardening Association