Scale

Scale

Scale insects are a common unwelcome visitor on many varieties of houseplants, and can spread a wide range of plant diseases, so it’s important to try and catch them early!

SYMPTOMS & IDENTIFICATION

Sometimes it can be difficult to identify a scale infestation, but a few key signs to look out for are:

  • Perforated, glossy and sticky leaves

  • Small, brown dots - mostly on stems, leaf joints and along leaf veins

Make sure to also thoroughly check the undersides of leaves. Although individual Scales are small, they tend to gather in clusters, which makes them easier to spot.

Scales 1

TREATMENT PLAN

Treatment: Scales are difficult and very time-consuming to get rid of. But if you want to give it a try, we recommend you to:

1. Isolate the affected plant

  • Place the infected plant in a closed room. Adult scales fix themselves in place on their host plant and so rarely move, however, it’s best to isolate the plant to avoid the spread of young scales, called ‘crawlers’

  • Make sure to also check all other plants for Scales

2. Cut off affected plant parts

  • This is only really recommended if it is a light Scales invasion, i.e. if the pests haven’t already spread too far across your plant, which could result in causing your plant too much trauma/damage if you cut too much from it

3. Fight mechanically by removing all visible Scales with tweezers

  • As Scales don’t tend to move around, it can be effective - but time-consuming - to physically remove them all. You can also treat it with insecticidal soap to loosen the Scales if they prove tricky to remove

  • Also make sure to wipe windows and wall surfaces where the plant has been

  • Repeat several times

4. Think about adding recommended pest control - (Scales can sometimes be biologically defeated with the beetle Cryptolaemus montrouzieri.)

Scales 3

HOW CAN I AVOID THIS HAPPENING AGAIN?

Regularly checking your plant’s overall health can greatly help to prevent a repeat infestation. If you do spot a few Scales, you can use a cotton swab to coat them with alcohol, which will cause them to detach from the plant. If you manage to do this early, it is much easier to prevent a full-scale outbreak.


QUESTIONS ABOUT SCALES

WHERE ARE SCALES USUALLY FOUND? These insects typically prefer warm, dry conditions, and can show up indoors or outdoors. They are usually brought in by introducing an infected plant - this is one of the reasons why it’s always a good idea to quarantine a new houseplant. There are actually over 8,000 different species of Scale, each with their own preferences for the type of plant/environment they like.

WHAT DO THEY EAT? Scales are sap-sucking pests, and they’re not fussy about which plants they feed on!

CAN THEY FLY? Some scales do have wings, but they don’t function particularly well, and so they are very unlikely to use them. The spreading of Scales is typically done during their ‘crawler’ stage.

WHY ARE THEY SO HARD TO GET RID OF? Scales are hardy and attach very firmly to their host plant. They also form an armor coating, which eggs are laid under, so it can be difficult to treat them directly and prevent spread, which is why mechanical removal is necessary. You may need to take several different steps/treatment options in order to eradicate them, especially if your plants are indoors, where there are no biological predators. Once you’ve physically removed all visible scales, make sure to follow-up with, for example, spraying a horticultural oil to eliminate the crawlers too.