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pests disease remedies

8 Common Pests – Plus Effective Remedies

So, You Have a Pest Problem?

You go to water your plant and notice something is wrong – what could it be? I’ve compiled a list of potential and common pests PLUS remedies (and prevention tips) to help nurse your plant back to health. Pictures are included to help you identify the particular plant ailment (you can find them at the bottom of the post).

The remedies discussed are nearly all non-chemical, but there are some chemical solutions used. I have compiled a list of resources from the Clemson Cooperative Extension Home & Garden Information Center about the treatments used in this post. Organic chemical solutions are still considered highly toxic to humans and animals. However, less toxic, non-chemical insecticides do exist, including insecticidal soaps and neem oil.

Note: When applying particular remedies, make sure the plant has been thoroughly watered and follow the label’s directions. Some houseplants – including jade plant and certain palms – are sensitive to insecticidal soap. Always spot test before treating the entire plant. In many cases, treatment will have to be repeated multiple times. Make sure you isolate the infected plant to prevent infestations from spreading.

Common Pests

1. Aphids and related insects
  • Appearance: very small – largest are 0.125in (3.175mm) – soft-bodied, pear-shaped insects; usually green, but can also be pink, brown, black or yellow; adults might have wings
  • Commonly found on new growth or undersides of leaves
  • Feed by sucking plant sap, resulting in yellowing and misshapen leaves; the longer the infestation goes unnoticed, the more likely aphids will cause plant growth to be stunted, new growth to be deformed, and even plant death
    • As aphids feed, they excrete a sugary material called ‘honeydew,’ which makes leaves shiny and sticky; ‘sooty’ mold may grow on the honeydew
  • Remedies:
    • Minor infestation: handpick, spray with water, or wipe away the insects with a cotton swab dipped in rubbing alcohol
    • Major infestation: spray leaves and soil with insecticidal soap or neem oil
2. Mealybugs
  • Appearance: small, largest are 0.25in (6.35mm); pale insects related to scales; mature females cover themselves and their eggs with a white, waxy material that resembles white wool or cotton
    • The wax on the insects repel pesticides, making it difficult to control them
  • Commonly found on underside of leaves and where the leaf attaches to the stem
  • Feed by sucking plant sap, causing similar plant problems as aphids
    • Like other common pests, they excrete honeydew
  • Remedies: wipe down the leaves and stem with a cotton swab dipped in rubbing alcohol; to ensure no insects are left in the soil, repot the plant; then spray with a 1:10 dilution of rubbing alcohol and water or neem oil
3. Scales
  • Appearance: two types, armored scales – which have a hard covering that can be scraped off to reveal the insect – and soft scales; anywhere from 0.06in (1.6mm) to 0.5in (12.7mm) in diameter; some are flat and appear stuck to the plant, while others look like colored blobs
    • Crawlers, which are young scales, can move around; adults cannot
  • Commonly found on the stems and the underside of leaves
  • Feed by sucking plant sap, causing similar plant problems as aphids and mealybugs
    • Only soft scales excrete honeydew, like other common pests
  • Remedies:
    • Minor infestations: removed by scraping scales off with a fingernail, since adults are relatively protected from insecticides by their waxy covering
    • Major infestations: spray leaves and soil with neem oil or canola oil, which controls the adult population by smothering them; crawlers are susceptible to neem oil, canola oil and insecticidal soap
4. Spider Mites
  • Appearance: More closely related to spiders; since they are so small, plant damage and webbing are usually how to detect an infestation
  • Feed by sucking plant sap, creating light-colored speckling on upper surface of leaves
  • Remedies: isolate infected plant and…
    • For sturdy plants: spray forcefully with water to dislodge the spider mites and break up the webs
    • For more delicate plants: spray leaves and soil with an insecticidal soap or neem oil
    • Repeat weekly until infestation is gone
5. Fungus Gnats
  • Appearance: can be spotted by large amounts of adult fungus gnats; first sign of infestation = plant loses its regular, healthy appearance
    • Fungus gnat larvae sometimes feed on roots, making them a ‘silent’ killer
  • Thrive in potting soil that is rich in organic matter and in wet environments
  • Remedies (& Prevention): if the plant can tolerate it, allow the soil to dry between waterings, since the drier conditions will kill the larvae
    • Do not allow standing water in saucers beneath houseplants for long periods of time and do not overwater
    • To deter future infestations, some recommend the “bottom watering” method:

1) pour water into a saucer or container beneath the pot

2) allow the plant to soak in the water for no more than 20 minute

3) once per month, thoroughly “top water” (aka, give your plant a ‘traditional’ watering) to wash away any salts and mineral buildup

    • this method prevents excess water from just sitting in the soil, which fosters the moist, wet environment fungus gnat larvae love
6. Thrips
  • Appearance: tiny – less than 0.06in (1.6mm) in length – slender, yellowish or blackish insects with fringed wings; blowing lightly into blooms and leaves can cause thrips to move, making them easier to spot
  • Commonly found on leaves and between flower petals
  • Feed by scraping surface cells to suck plant sap; damaged leaves from thrips will look speckled, similar to the damage done by spider mites
  • Remedies: prune injured plant areas; spray leaves and soil with insecticidal soap or neem oil
7. Springtails
  • Appearance: tiny – about 0.2in (5mm) in length – and vary in color; wingless, but can jump
  • Found in the soil; presence is a sign of overwatering
  • Chew on seedlings or tender plant parts
  • Remedies: follow remedies and prevention treatment for fungus gnat larvae
8. Root Ball Pests
  • Plants taken outdoors during the warmer months may have their root balls infested with pests – including pillbugs, millipedes, and ants – which can cause damage to the root systems
  • Remedies:
    • remove plant from soil
    • carefully remove any clinging dirt from the root system
    • submerge the entire root ball in a container of water for at least 30 minutes
    • repot with new, fresh soil

Images of Common Pests

Need help diagnosing your plant? Comment below or email me your plant’s symptoms and a picture for help identifying which common pest is harming your plant.