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New forest pests in a changing climate

The issues for in this project are:

  • To study the life history of the Hungarian spruce scale and two related species, including pheromone/ kairomone communication and temperature/day length requirements.
  • To understand the environmental conditions triggering an outbreak. This includes interactions between host tree and pest.
  • Ecosystem modeling for climate change impact assessment, based on the acquired results.

This challenging project aims to value the pest potential of the scale insects in toto including climatic influences on host and insects. In the same framework it also aims to provide methods to monitor and predict potential outbreaks and to offer (sustainable) management strategies for these insects (e.g. monitoring traps).

Odour collection

Above a picture showing odour collection from Hungarian Spruce Scale, Physokermes inopinatus. Below a close-up of the vial. Photos: Inis Winde.

Physokermes scales


Forests are important resources for renewable materials and bioenergy (biofuel) and are rapidly becoming an important substitute for fossil fuels. At the same time climate change and human activities, such as trade, make it easier for new pest insects and pathogens to spread to and establish in new areas. Therefore new methods to monitor potential pest insects and to predict and manage outbreaks are needed.

The Hungarian spruce scale (Physokermes inopinatus) was first recorded in Hungary and described as late as 1973. Since then it has been recorded from southeastern Europe, but suddenly, in 2010, it was detected in the very south of Sweden. Together with accompanying fungi it severely affected more than 1000 hectares of which a considerable part had to be cut. In addition to the Hungarian spruce scale two other Physokermes species feeding on coniferous trees have been described. In general very little is known about the environmental requirements and life cycles of these potential pest insects, which make it difficult to assess the risks associated with these scale insects.

Recent publications

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Physokermes female with eggs
Physokermes inopinatus female on Norway Spruce. One female can lay several thousands of eggs which develop safely inside the female shell which at this stage is swollen like a blister (as can be seen in the picture). Photo: Inis Winde.