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Alder Leaf Beetle Survey

PLEASE NOTE – This survey has now closed and future records should be made on this website or direct to iRecord.


One of our members has made the following request for more Alder Leaf Beetle (Agelastica alni) records.

Although they are common enough not to require all local records simply for distribution purposes, they have recently been reported defoliating apple trees. This is new behaviour for the UK (it’s well known on the continent) and they are also known on other Rosaceae (fruit trees including apple, pear, plum, cherry etc., as well as bramble, rose, hawthorn, blackthorn etc.). So, if people could submit records to [survey ended] including the plant host along with the usual location, date, approx numbers and recorder name, that would be much appreciated.

Alder Leaf Beetle (Agelastica alni)


Size: 6-7mm
Basic colour: Deep metallic blue with a violet reflection.
Pattern colour: None
Number of spots: None
Other colour forms: Sometimes
Pronotoum: Deep metallic blue with a violet reflection.
Leg colour: Deep metallic blue with a violet reflection.
Has been considered in immigrant species, but this is not certain. Much life cycle information is from populations in France where new adults emerge in July and August, feed on alder leaves for 12-15 days, then enter a diapause on the ground surface, followed by hibernation until spring. Larvae usually feed on leaves of alders, but can develop on Downy Birch, Hazel and Goat Willow. Pupation occurs in an earth cell just below the ground surface, or in leaf litter. Adults can fly, but flight activity is low.