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Combating scale insects
Are you bothered by hard, brown bumps on the stems or leaves of your plant? Then you are probably dealing with scale insects. This persistent pest is a common problem with various houseplants, but also with plants in the garden or greenhouse. Especially plants with hard leaves, such as the Strelitzia, Ficus, Citrus trees, and various types of Palms, are favorite targets. Tackling these little intruders in a timely manner is essential to prevent your green friends from slowly withering away. In this blog, you can read more about combating scale insects.
Identifying Scale Insects
Scale insects often do not stand out immediately because they do not move and look like small, natural growths on the plant. You can recognize them by the following characteristics:
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Hard scales: Small, round or oval bumps that are brown, gray, or yellowish in color.
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Sticky leaves: Scale insects secrete honeydew, a sticky substance that ends up on the leaves or even on the windowsill under the plant.
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Yellow spots: The plant's leaves may turn yellow or even fall off because the aphid sucks the sap from the plant.
What is a Scale Insect?
Scale insects are a collective name for a group of insects that protect themselves with a hard, waxy shield. This shield is not attached to the insect's body but functions as a kind of armor. As a result, they are much more difficult to control than, for example, aphids. Underneath this shield, the insect sucks up plant sap undisturbed, which weakens the plant and inhibits growth.
Preventing Scale Insects
Prevention is better than cure. Scale insects prefer plants that already have reduced resistance.
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Check new plants: Inspect every new addition thoroughly before placing it with your other plants.
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Good humidity: Scale insects love dry air. Spray your plants regularly with a plant sprayer to increase the humidity around the plant.
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Location: Ensure your plant is in the right place (not too drafty and not directly above a blasting radiator). A healthy plant is less susceptible to pests.
Controlling Scale Insects
Because of their hard shell, these insects are immune to many mild pesticides. An effective approach requires patience:
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Manual removal: Do you have only a few lice? Use a cotton swab dipped in alcohol or a blunt knife to carefully scrape the scales off the plant.
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Isolation: Immediately separate the infected plant from your other plants to prevent further spread.
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Oil-based agents: Oil-based agents (such as rapeseed oil or neem oil) are very effective. The oil forms a layer over the shield, causing the louse to suffocate.
Can green soap combat scale insects?
Green soap is often cited as a miracle cure, but the results for scale insects are mixed. The soap attacks the outside of insects, but the hard shell of the scale insect offers a lot of protection. A mixture of green soap and methylated spirits (approximately 20 grams of soap and 10-20 ml of methylated spirits per liter of water) is more effective, because the methylated spirits help to penetrate the waxy shield.
Frequently Asked Questions about Scale Insects
Is scale insect contagious to other plants?
Yes, most certainly. Although the adult insects do not move, the 'crawlers' (the newly hatched larvae) can move to nearby plants. They can also be transmitted via your hands or clothing.
Can scale insects harm humans or pets?
No, scale insects are purely focused on plants. They do not bite and are not harmful to the health of humans, dogs, or cats. However, the sticky honeydew can attract fungi (such as sooty mold) that are unhygienic in the home.
Why do scale insects keep coming back?
Scale insects lay eggs under their shells. Even if you remove the adult insects, eggs can remain in small crevices or in the soil. Therefore, always repeat the treatment after two weeks to tackle the new generation.
Combatting scale insects requires patience, but with the right method and regular checks, your plant will recover in no time. Remain alert for new bumps after treatment so that you can intervene immediately.
