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Scots Pine Adelges

Pineus strobi

Scots Pine Adelges

A close up of  Pineus pini Scots pine adelges on Scots pine with their white waxy secretions
Scots Pine Adelges are closely related to aphids. They're able to alternate reproduction strategies to produce as much offspring possible. They also produce white waxy secretions, which they use as protection against pathogens. This secretion makes it difficult to apply chemical treatments to these insects. As well as the latter, they produce honeydew too, which can encourage the growth of black sooty moulds, which may attract further infections. These adelges show similarities to Weymouth Pine Adelges. They will only visit one host plant during a life cycle, in this case, is Scots Pine.
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Adelgid larvae cause galls to form on the host plant, which in most cases are harmless, however unsightly.
Adelgids produce honeydew as a by-product from feeding. Honeydew is normally associated with a build-up of black sooty mould.


Nymphs overwinter on Scots pine (Pinus sylvestris). Nymphs mature, turning a darker brown as they develop. Fully grown adults eventually turn red in colour. They are about 2mm in length normally. Early spring, adults lay more eggs, which will eventually hatch and grow into both winged and wingless morphs. Winged forms will migrate and infest more Scots pine, whereas wingless morphs generate a further generation on the original plant.


The white waxy deposit that's secreted by this insect may disfigure pine. Damage caused by this pest has been described as minor.











Europe and North America.

Biological treatment

Damage caused by adelgids is often minimal and infestations tend to be tolerable.

Chemical treatment

Adelgids can be difficult to control chemically due to the waxy secretions they are able to secrete. These waxy coatings act as a layer of protection from things like fungi and bacteria. Likewise, host plants are often too large to treat completely, so chemical treatment can sometimes be ineffective. If you do decide to use a chemical treatment, it's advised to carefully read label instructions before using any product on the surrounding environment.


A close up of a Pinus sylvestris plant

Scots Pine

Pinus sylvestris

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