Nerve plants (Fittonia spp.) are compact tropical houseplants with colorful red, pink, or white veins on their leaves. Also known as mosaic plants, nerve plants can also be grown outside in USDA Zones 11 and 12 and offer a host of uses and benefits. In this article, we’ll run through 10 common nerve plant pests, bugs, and diseases, including how to identify and mitigate issues when they crop up.
Common Nerve Plant Pests and Diseases – The Essentials
Nerve plants can fall prey to pests like aphids, fungus gnats, and thrips. Root rot is a common problem caused by overwatering. Nerve plants growing outside can suffer from powdery mildew or southern blight. Use horticultural oils, insecticidal soap, and fungicides to deal with pests and diseases.
10 Common Nerve Plant Pests and Diseases and How to Identify Them
1. Aphids
Aphids are small black or green insects that can attack nerve plants growing outside. These insects suck sap from nerve plants and often hide underneath leaves. Aphids cause various problems, such as black mold, misshapen leaves, and stunted growth.
Dislodge aphids from your nerve plant using a hose. Alternatively, use horticultural oils or insecticidal soap to remove aphids. Pesticides should be a last resort.
2. Fungus Gnats
Fungus gnats are annoying flying insects that attack houseplants like nerve plants. However, adult gnats aren’t the real problem. It’s the larvae that cause damage to nerve plants by consuming the roots underneath the soil.
Adult fungus gnats lay eggs in the top 2 or 3 inches of moist soil. A single gnat can lay up to 150 eggs in one week. Kill adult gnats using sticky traps or bottle caps filled with almond oil. Replace the top 2 or 3 inches of soil to remove the larvae.
3. Mealybugs
Mealybugs are a type of scale insect that often attack houseplants. As they graze, mealybugs leave behind sticky white deposits of honeydew as well as black sooty mold. You may also spot the insects as tiny white blobs on your nerve plant.
Use horticultural oils or insecticidal soap to remove mealybug infestations. If your nerve plant is suffering from a severe infestation, you may have to discard the plant.
4. Spider Mites
Spider mites are common pests that feed on plant cells, leading to yellowing or browning leaves that drop off. These mites leave webbing around affected leaves and can be spotted moving around the plant. As spider mites feed, they cause yellow or brown speckles to appear on nerve plant leaves.
Eliminate spider mites using horticultural oils or insecticidal soap. You can also use biological control measures such as predatory mites or nematodes.
5. Thrips
Thrips are tiny, thin black or brown insects that feed on plant sap. As thrips feed, your nerve plant may display silver marks or stippling on its leaves. Thrips can also cause stunted growth, and affected leaves may drop off.
Use horticultural oils or insecticidal soap to get rid of thrips. You can also use sticky traps to eliminate adult thrips to prevent them from laying more eggs.
6. Mosaic Virus
Mosaic virus is a debilitating disease that can severely affect nerve plants. This virus can spread quickly from plant to plant through leaf contact. Symptoms of mosaic virus include yellow or green mottling on infected leaves.
Mosaic virus cannot be cured, so infected nerve plants will have to be disposed of. If your nerve plants are close to other plants, create space between them to minimize the risk of infection.
7. Powdery Mildew
Powdery mildew is a common fungal disease that can infect nerve plants growing outdoors or in a greenhouse. This occurs when conditions are hot and dry during the day and cold and wet at night. Symptoms of powdery mildew include dusty white patches on the leaves and stunted or misshapen growth.
Allow space between your nerve plant and other plants to improve airflow. Avoid overwatering or splashing water on the leaves. Water in the morning to prevent nerve plants from sitting in water during cold nighttime temperatures.
8. Root Rot
Root rot is a common problem for houseplants, especially those that like moist soil. Overwatering is the leading cause of root rot in nerve plants. Root rot occurs in waterlogged soils and causes yellowing leaves and drooping foliage.
Check the soil around your nerve plant to see if it’s soggy, then lift the plant and check the roots. Remove any brown, mushy, or smelly roots and repot your nerve plant in fresh soil. Add drainage using horticultural sand or perlite, and avoid watering unless the top inch of the soil feels dry.
9. Southern Blight
Southern blight is a fungal disease that can infect nerve plants. It’s caused by Sclerotium rolfsii fungus and attacks nerve plants from within the soil. Southern blight causes discoloration and wilting of the leaves. You may also spot white lines of mycelia on the stems.
Remove the infected soil if your nerve plant is infected by Southern blight. Then repot or replant your nerve plant into fresh soil. Southern blight thrives in warm, wet conditions, so avoid overwatering or waterlogged soil.
10. Xanthomonas Leaf Spot
Nerve plants growing outside can suffer from Xanthomonas leaf spot. Leaf spot diseases are caused by fungal spores that thrive in wet, humid conditions. As nerve plants require tropical conditions in Zones 11 and 12, this leaves them vulnerable to leaf spot.
Xanthomonas leaf spot causes small spots ringed by yellow and can also cause necrosis. Remove affected foliage and treat remaining leaves with horticultural oils. Water your nerve plant at the base of the stems to avoid getting water on the leaves.
Pesticide and Insecticide Options and Solutions
Horticultural Oils
Horticultural oils can tackle several nerve plant pests and are commonly available in grocery stores or garden centers. Canola oil and neem oil are two of the most common. Horticultural oils interrupt the breeding cycles of aphids and other pests, helping you control numbers without the need for chemicals.
Insecticidal Soap
Insecticidal soap is highly effective against pests like aphids or mealybugs. This solution works by drying out or suffocating pests. If you can’t find insecticidal soap, you can make a similar solution by mixing dish soap in warm water.
Biological Controls
Biological controls come in many forms but are usually predatory organisms such as mites or nematodes. These organisms attack certain pests like aphids or fungus gnats. Mosquito dunks are also a form of biological control and work especially well against fungus gnats. Make sure to choose the right biological control for the pest you’re trying to combat.
Pesticides and Fungicides
Pesticides and fungicides can help you eliminate stubborn pest infestations or fungal infections. If you can, use organic pesticides or fungicides, as synthetic products contain lots of chemicals. These chemicals can kill beneficial bacteria, negatively impacting the quality of the soil around your nerve plant. Always use these products carefully and sparingly.
Sticky Traps
Sticky traps are an easy way to curb populations of pests like fungus gnats or thrips. These traps catch adult pests, which prevents them from laying more eggs. Gradually, the infestation should dissipate.
Managing Pests and Diseases
The best way to protect your nerve plant from pests and diseases is to give it the best possible care. Nerve plants need bright, indirect, or filtered sunlight, ideally from an east-facing window. Partial shade also works well, especially when growing nerve plants outside.
Nerve plants require warm, humid environments with temperatures between 60 and 80ºF and humidity levels between 60 and 90%. To reduce the risk of fungal diseases, provide plenty of space around each plant to promote good airflow. Only water nerve plants if the top inch of the soil feels dry. This usually equates to every 3 to 4 days in the summer.
Nerve plants require moist soils that are still well-draining. Waterlogged soil encourages the growth of fungal spores and is caused by overwatering. Ensure that the soil has good drainage by adding in some perlite or sand. It’s also worth fertilizing nerve plants monthly during the spring and summer.
Position nerve plants away from drafty areas that can lower the temperature or humidity around the plant.
Wrapping Up
Nerve plants can suffer from pests and diseases such as aphids, mealybugs, powdery mildew, mosaic virus, and root rot. If you spot pests on your nerve plant, eliminate them using horticultural oils or insecticidal soap. Prevent diseases or pests from attacking your nerve plant by providing the best possible care, and your plants will thrive for years to come.
Andrew is the Editorial Director at Petal Republic. He holds a BSc degree in Plant Sciences and has trained professionally at leading floristry schools in London and Paris. In amongst overseeing a global editorial team, Andrew's a passionate content creator around all things flowers, floral design, gardening, and houseplants.
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