Agelastica alni
This is an alder leaf beetle. The adult beetles munch holes in leaves, but the real damage is done by the hordes of larvae that appear from late spring onwards. These look like small black caterpillars - at one time I thought they were sawfly larvae - and can quickly convert leaves to skeletons.
This year these beetles are everywhere. Whilst their preferred food plant is alder I've seen them on many different plants such as this dandelion. I've seen adult beetles actively eating laurel and hawthorn, although damage is minimal compared to the local alders which are already virtually defoliated.
Agelastica alni
This is an alder leaf beetle. The adult beetles munch holes in leaves, but the real damage is done by the hordes of larvae that appear from late spring onwards. These look like small black caterpillars - at one time I thought they were sawfly larvae - and can quickly convert leaves to skeletons.
This year these beetles are everywhere. Whilst their preferred food plant is alder I've seen them on many different plants such as this dandelion. I've seen adult beetles actively eating laurel and hawthorn, although damage is minimal compared to the local alders which are already virtually defoliated.