Pests of the Sage Plant

Sage is a perennial plant that is popular as both a flowering plant and culinary herb. Few pests bother it, making sage a good companion plant. Several insects do like sage, however, including spider mites, whiteflies, thrips, spittlebugs and aphids.

Spider mites thrive in the hot, dry conditions that sage enjoys. They also prefer the furry leaves that are typical of sage. Spiders mites can be difficult to get rid of and require diligent removal efforts. Treatment can include spraying the plant, especially the underside of the leaf, with insecticidal soap or a permethrin concentrate. Predatory insects--such as green lacewings, lady beetles and minute pirate bugs--are effective as well.

Thrips are tiny slender insects with fringed wings, depending on their stage of development. They cause the leaves to have a bleached or stippled appearance, because they feed on the growing parts of the plants. Using water spray to knock them off the plants can sometimes control thrips. Several predator bugs--such as predatory mites, parasitic wasps and green lacewings--can be used against them as well.

Spittlebugs, also known as froghoppers, can be a pest on sage. They are attracted to plants that have more amino acids carried in the xylem, which they feed on. The spittle nests can be washed off by spraying the plant, though the nymph, if it survives, will climb back on the plant and rebuild the nest. The adults feed on the xylem as well, so you can use insecticide spray can if spittlebugs become a problem.

Whiteflies cause problems because they feed on the sage plants and can transfer viruses and diseases between plants. Whiteflies can be problematic because they develop resistance to insecticides fairly quickly. Washing the underside of the leaves and using predator insects--such as green lacewings, lady beetles, minute pirate bugs and damsel bugs--can remedy a whitefly infestation. Because whiteflies are attracted to the color yellow, you can also use yellow sticky traps.

Aphids can cause major problems with sage. They are a very invasive pest but can be controlled fairly well with biological means and if necessary, pesticides. The first method of attack if your sage has been infested with aphids can include a thorough rinsing with a strong enough spray to knock them off the plant. This will need to be repeated daily until there are no more aphids. Lady bugs, green lacewings and aphid midges are some of the more effective biocontrols.