Pansies are perennials that grow well in part to full sun when watered regularly. Unfortunately, pansies attract several pests that eat the flowers or leaves, causing poor appearance, slow growth and even death.
Several pests damage pansies by eating the flowers, leaves or other parts of the plant. This includes flying insects such as aphids and whiteflies, along with bugs such as spider mites, slugs and snails.
Aphids are soft-bodied, winged insects about 1/2-inch long that may be tan, black, pink or green in colour. Small spider mites are hard to see with the naked eye, but sometimes leave fine webbing on leaves. Slugs and snails are soft-bodied animals that leave behind slimy trails where they travel. Identify whiteflies by their yellow bodies and white wings.
Slugs and snails leave large holes in the plant in no particular pattern. Aphids eat pansy leaves and stems while excreting clear, sticky honeydew on plant parts. Two-spotted spider mites suck plant sap from pansies, making small holes in the leaves where tan spots later develop. Both the greenhouse and silverleaf whiteflies suck leaf sap, causing yellowing, drying and leaf loss.
Insecticides work against spider mites and sometimes aphids. Use natural enemies such as lady beetles and lacewings as the first line of defence. Remove leaf and plant debris where slugs and snails stay during the day. Remove adult whiteflies by hand and consider insecticidal soaps or horticultural oils if necessary as a last resort.