Chris Malumphy, Senior entomologist at Fera, has issued a warning on the globose scale or plum lecanium on the observatree website.
Scale insects are highly specialised plant parasites related to aphids. They are responsible for large scale damage to cherry, plum and peach trees. Originally from southern and central Europe, Fera have compiled a large set of evidence to suggest they are expanding into northern Europe as a result of climate change.
As temperatures continue to grow previously uninhabitable areas for these scale insects are now feeling the effects of large scale insect migration.
Fera have recorded the presence of scale insects such as globose scale in Brussels, Belgium. This could indicate their migration toward the UK.
"It may be able to establish in parts of southern England and is a potential pest of plum, peach and cherry," he said. "The insects damage the host plants directly by extracting large volumes of plant sap and indirectly by the black sooty moulds that grow on the honeydew, reducing photosynthesis and gas exchange."
These insects are notoriously difficult to identify, with their unique shape they have a track record of fooling potential researchers into believing they are not insects at all and instead berries or other plant matter. Adult female globose scales are about 2.5mm across, strongly convex to almost circular, while young adults are yellow with longitudinal rows of black spots that may coalesce, turning reddish-brown with maturity. They are largely immobile compared to their male counterparts who have developed wings and as such are more ‘insect-like’.
Due to the potential damage these insects can cause to food producing trees and plants it is important to report any suspected outbreaks via the Forestry Commission’s Tree Alert service.
More information can be found here:http://www.observatree.org.uk/globose-scale/
21 April 2017
09 March 2017