Most Common Licorice Plant Pests:
Identification and Treatment Guide

Licorice plants, also known as Glycyrrhiza glabra, are popular perennials that are widely grown for their medicinal properties and attractive foliage. These plants are relatively low-maintenance but can still be susceptible to pests that can damage their leaves and roots. In this article, we will explore some of the most common licorice plant pests, how to identify them, and effective treatment methods.

Aphids

Aphids are small, soft-bodied insects that commonly attack licorice plants. They feed on the plant’s sap by piercing the leaves and stems with their needle-like mouthparts. Aphids can quickly multiply and cause significant damage if left unchecked.

Identification: Aphids are usually green or black in color, but they can also be yellow or brown. They are about 1/8 inch long and have a pear-shaped body. When present in large numbers, aphids can be seen clustering on leaves and new growth.

Treatment: To control aphids on licorice plants, you can start by spraying a strong stream of water on the affected parts to dislodge them. You can also introduce natural predators like ladybugs and lacewings, which feed on aphids. If the infestation is severe, you may need to resort to insecticidal soaps or neem oil sprays.

Spider Mites

Spider mites are tiny pests that belong to the arachnid family. They thrive in hot and dry conditions and often infest licorice plants during the summer months. Spider mites feed on plant sap by piercing the leaves with their mouthparts, causing yellowing and stippling.

Identification: Spider mites are difficult to see with the naked eye due to their small size. However, you may notice fine webbing on the undersides of leaves, which is a telltale sign of their presence. Affected leaves may also appear discolored and have a stippled or mottled appearance.

Treatment: To control spider mites, regularly mist the leaves of your licorice plant to increase humidity and discourage their growth. You can also use insecticidal soaps or horticultural oils to suffocate the mites. In severe cases, you may need to resort to chemical miticides, but use them sparingly as they can harm beneficial insects.

Whiteflies

Whiteflies are small, winged insects that are often found in clusters on the undersides of licorice plant leaves. They suck sap from the plant, causing damage similar to aphids. Additionally, whiteflies excrete a sticky substance called honeydew, which can lead to the growth of black sooty mold.

Identification: Whiteflies are tiny, white insects that resemble tiny moths when disturbed. They are usually found on the undersides of leaves, where they lay their eggs. Infested leaves may appear yellowed and distorted.

Treatment: To control whiteflies, you can start by physically removing the affected leaves and disposing of them properly. You can also introduce natural predators like parasitic wasps or apply insecticidal soaps or neem oil sprays. Sticky traps can be used to monitor and capture adult whiteflies.

Root Knot Nematodes

Root knot nematodes are microscopic worm-like organisms that live in the soil and feed on plant roots. They cause galls or knots to form on the roots, disrupting water and nutrient uptake. Licorice plants infested with root knot nematodes may exhibit stunted growth and yellowing leaves.

Identification: Identifying root knot nematodes requires examining the roots of the plant. Infested roots will have visible knots or galls, which are small swellings caused by the feeding activity of the nematodes.

Treatment: Unfortunately, once a licorice plant is infested with root knot nematodes, it is challenging to eliminate them completely. However, there are some management techniques that can help reduce their impact. These include crop rotation, using nematode-resistant varieties, and improving soil health through organic amendments. Additionally, solarization can be effective in killing nematodes in the soil by covering the area with clear plastic during hot summer months.

Slugs and Snails

Slugs and snails are common garden pests that can feed on licorice plant foliage, leaving behind large irregular holes. They are most active during cool and damp weather conditions, often causing damage overnight.

Identification: Slugs and snails are mollusks with soft bodies and no legs. They leave behind a slimy trail as they move and feed. You may also notice chewed leaves and stems, as well as silvery slime trails on the ground around your licorice plants.

Treatment: To control slugs and snails, you can manually remove them from your plants by handpicking or using traps like saucers filled with beer or yeast solution. Creating physical barriers like copper tape or diatomaceous earth around your plants can also deter these pests. Additionally, applying iron phosphate-based slug baits can be effective but use them sparingly and follow the instructions carefully.

In conclusion, while licorice plants are generally hardy, they can still be susceptible to various pests that can damage their foliage and roots. Regular inspection and early intervention are essential to prevent pest populations from getting out of control. By implementing the appropriate identification and treatment methods discussed in this guide, you can keep your licorice plants healthy and thriving.