3rd October 2019

Alder Beetles- if like me, you are seeing Alder leaves full of holes and wondering what’s eating them it is the (unimaginatively but accurately named) Alder Beetle. This tiny, shiny metallic blue beetle which was in plentiful evidence at Potteric Carr nature reserve near Doncaster last week, was thought to be extinct in the UK for sixty years but has recolonised northwards after being recorded in Hampshire in 2004. The Alder Beetle, about 6-7mm long, is most active from April to July but there were many in evidence in the South Yorkshire Wildlife Trust reserve at the end of August. The caterpillars are also black and feed on Alder too, and the adults overwinter in leaf-litter before emerging to lay their eggs next spring. It sometimes affects Beech as well as Alder but the trees seem to survive the infestations. Conditions: Cool, still, grey.

Alder leaf eaten by Alder Beetle

Alder Beetle on Alder leaf

Temperature: Max 12 Min 10C.