Scale bugs, of the Coccoidea family are roundish, oval disc looking bugs that have soft outer shells, and visually look light brown/orange. They attach themselves to the leaves and stems of plants and suck out the plant sap.
Scientific name/ Super Family: Coccoidea
Higher Classification/sub order: Sternorrhyncha
Order: True bugs
Their droppings/waste are honeydew type sugar deposits that if not eaten by worker ants, then the deposit quickly becomes colonized by mould, the mould weakens almost eroding part of the stem, this allows plant disease to take hold of the plant.
So, if you do have scale bugs here is how you treat them, there are many treatments available, here are a few that can be misted onto your plants with minimal withholding periods:
- Diluted ethanol or alcohol spray (approx. 40%)
- Limonene Solution
- Neem Oil
- Sesame Oil
- Clove & cinnamon oils
For a more organic approach the gardener can integrate predatory insects that feast on the unwanted infestation/s, here are a few of the most commonly used predators to fight scale bug:
- Parasitic wasps (Metaphycus helvolus, Anagyrus pseudcocci)
- Orius Species of Minute pirate bug, will eat scale & mealybugs
- Lady bugs (Ryzobius lophanthae) also eats aphids
Prevention as always is better than clambering to find a cure, always inspect your plant stems as well as new internodal growth, if you find early or just implementing a regime that can control a potential outbreak.
Most annuals do fine, anything older is generally much more susceptible, especially Mother plant stocks!