Scale insects are a common sap-sucking pest on many plants and can vary dramatically in their appearance. There are over 8000 species of scale insects, superfamily Coccoidea, ranked in the order Hemiptera, suborder Sternorrhyncha, which makes them true bugs and related to aphids, whiteflies, and mealy bugs.
As a defence, they secrete a waxy substance impervious to most liquids, and the wax from one species, Kerria lacca, being so durable that it was used to make shellac. Because of this coating, they are quite resistant to many pesticides and can be hard to eradicate once an infestation has set in.
Common methods of control are usually the spraying of oil-based agents like white summer oil that work primarily by suffocation, or the treatment of systemic pesticides that make the plant's sap and tissues toxic to the pests. Light infestations can be removed using ethanol or rubbing alcohol, which dissolves the waxy coating on the insects. Even after the insects die, their bodies remain on the plant until the waxy coating is degraded, which takes a fairly long time.
An alternative that works very well is the Sodasan Orange Cleaner. Only 1 ml or 2 ml (a squirt of the bottle) to 500 ml of water is needed to make an effective solution that dissolves their coating and makes their removal easy without damaging plant leaves.
The photos above show how heavy the infestation was on this orchid before and after application using a small cotton pad with some light rubbing. As a bonus, this cleaner can also be used for degreasing areas in the home like stoves and ovens and leaves a pleasant orange scent. No wonder as it is made from orange peel oil.
Finally, an easy and non-toxic way to control these pesky bugs!
Note: Sodasan Orange Cleaner can be found at Fairprice Finest or Redmart, prices range from S$9.90 - $$10.50 for a 500ml bottle. This is not a sponsored post. For sensitive plants, it is advisable to test on a small area first before treating the entire plant. Ingredients: Sugar surfactants, Water, Coconut alcohol sulphate, Orange oil, Essential oils (Limonene, Linalool).