Dead Nettle Pests

Dead Nettle, also known as Lamium maculatum, is a ground cover known for tiny blooms and variegated foliage. This perennial grows in zones 4 through 8 and is easy to maintain. Several pests can damage the health and appearance of Dead Nettle plants. Controlling and preventing an infestation is key to growing healthy Dead Nettle.  

Common Dead Nettle Pests

Whiteflies

Whiteflies are tiny insects with white bodies that measure just a fraction of an inch in length. They are often found in groups on the underside of leaves. These pests are sap suckers that latch onto the foliage and strip the plant of nutrients. Infested plants will experience stunted growth and leaf loss. These pests leave waste, known as honeydew, on the plant that can develop into black sooty mold. Whiteflies appear later in the summer when the temperatures and humidity are high.

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Photo by Scot Nelson

Treating Whiteflies on Dead Nettle

Immediately treat whiteflies on Dead Nettle by spraying the plant with water to knock off the insects and their eggs. Follow up by spraying the plant with insecticidal soap. Spray the plant several times over the next few weeks to remove any additional whiteflies or eggs and prevent another outbreak. Remove dead or damaged growth so the plant can direct energy into new healthy growth.

Preventing Whiteflies on Dead Nettle

Ladybugs and dragonflies are natural predators of whiteflies, so do not remove these beneficial insects from your landscape. Beneficial insects can keep whiteflies under control and prevent these pests from harming Dead Nettle. Proactively spray plants with insecticidal soap or horticultural oil to prevent whiteflies. Make sure to spray under the leaves, where the insects are likely to be found, and where they lay their eggs.

Aphids

Aphids are common sap-sucking insects that can cause significant damage to Dead Nettle plants if left untreated. Signs of aphid damage include yellow leaves that are curled or twisted, stunted growth, and leaf loss. Honeydew, the aphid waste found on the lower foliage, is another sign these pests are infesting your Dead Nettle.

Treating Aphids on Dead Nettle

Treat aphids on Dead Nettle by spraying the plants with water to remove the adults, larvae, and eggs. Use an insecticidal soap or horticultural oil to kill any pests on the plant. Continue to spray the plant for several weeks after the initial treatment to ensure all of the aphids are removed. 

Preventing Aphids on Dead Nettle

Preventing aphids on Dead Nettle plants can be challenging because these insects are common. Spray the plants proactively with horticultural oil or insecticidal soap if you have dealt with these pests in the past. Healthy plants are also less susceptible to aphid damage, so keep your plant watered and protected from harsh afternoon sun. Sometimes catching an infestation early is the closest you can get to prevention.

Slugs

Slugs are soft-bodied pests that eat vegetation. It’s always disappointing when slugs damage a plant, but it's especially upsetting when they eat the beautifully variegated foliage of Dead Nettle. Slugs are big enough to be spotted on plants and leave irregularly shaped holes in leaves as a sign of their presence. Slugs can quickly take down a plant by eating the new foliage in early spring.

Treating Slugs on Dead Nettle

The easiest and quickest way to treat slugs on Dead Nettle is to remove them from the plant as you see them. During the day, slugs can be found hiding out on the underside of the leaves or the ground around the plant. Slugs are more active in the evening, so manually removing them may be easier in the evening. Another treatment method to eliminate slugs is to set out a short jar with an inch or two of beer. The beer will entice the slugs, and they’ll drown when they crawl into the jar. Commercial products like Sluggo can also be applied as needed.

Preventing Slugs on Dead Nettle

Prevent slugs on Dead Nettle by making it uncomfortable for them to reach the plants. You can encircle the plant with copper tape or wool pellets. You can also try sprinkling commercial slug bait around the plant to target slugs. Clean up the area around the plant to remove hiding spots for the slugs.

Sources: "Deadnettle, Spotted - Lamium maculatum." University of Illinois Extension. web.extension.illinois.edu

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Author Alison Cotsonas - Published 05-16-2023