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Scale Insects


Scale Insects

Usually appear in

Spring and Summer

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Caused By:-     Several types of insects


These Scale insects are indoors on a climber on my front window. They reproduce fast and went unnoticed for some time.
Scale insects are sap-sucking, limpet-like insect pests that weaken the growth of the host plant and can infest a wide range of ornamental plants and fruit trees.
They are usually easily seen as scales or shell-like bumps on plant stems and the underside of leaves. These are the outer coverings of scale insects.
Many species excrete a sticky, sugary substance, called honeydew, on the leaves and stems on which they feed leading to the attraction of other insects like ants and bees and secondary, usually black, sooty, mould growth. Ants then protect the scale insects from their predators so they can farm the honeydew.
Several scale insects usually only affect indoor plants or plants in a very sheltered spot.
The main families of scale insects are:- Asterolecaniidae(pit scales), Coccidae(soft scales), Dactylopiidae(cochineal), Diaspididae(armored scales), Eriococcidae(felted scales), Kerriidae(lac scales), Margarodidae(cottony cushion scales, giant coccids and ground pearls), Pseudococcidae(mealybugs).
See these other Scale insects Azalea Bark, Azalea Cottony, Beech Bark, Brown, Eucalyptus Gumtree, Euonymus Mussel, Hemispherical, Horse Chestnut, Hydrangea, Juniper, Mussel, Oleander, San Jose, Soft, Viburnum Cushion, Wisteria, Wooly Vine.


In warm environments, like greenhouses, biological control can be used in greenhouses with a parasitic wasp, Metaphycus helvolus. This attacks two species of scale insect, soft scale (Coccus hesperidum) and hemisperical scale (Saisettia coffeae).
The shell or scale protects the older insects from insecticides, so spraying is more effective against the newly hatched nymphs, called crawlers, which have legs and can move about.
With scales on outdoor plants there is usually one generation a year and in most species the eggs hatch in late June to July, when spraying should be commence.
Scales insects in greenhouses or on houseplants breed throughout the year so all stages in the life cycle may be present at the same time.
Scale insects can remain attached to the plant long after they are dead but new growth should be free of scales once they have been brought under control.
On indoor plants systemic insecticide is best as the outer scale usually protects the insects inside.
Brushing of the insects with methylated spirits can be tried or if the infestation is light picking off the individual insects along with keeping an eye out for young hatchings.

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