September
Adult beetles may start to emerge from winter
shelter.

If they emerge too early, they are likely to die from lack of food (elm leaves). In heavily infested areas
the beetle can be a pest inside houses, sheds and caravans.

October
Most adult beetles emerge from shelter during
October, fly to nearby Elm trees and start to feed on newly emerging leaves. The beetle is small and usually hard to spot, however the ‘shot hole’
damage to the leaves, resulting from their feeding,
is easily seen.

November
The beetles mate and lay their eggs on the Elm leaves which then start hatching after 7 days.

December
From late November the larvae (grubs) hatch from the eggs, growing from about 1mm to 10mm. They feed on and skeletonise the Elm leaves.

Where there are heavy infestations, the trees are rapidly defoliated. Then the Larvae move down the branches and trunk to pupate. About 5mm long, oval and bright yellow, the pupae can be seen on the ground at the base of the tree and in the textured bark. After about 10 days new adults emerge.

January ~ March
Depending on environmental conditions, a second generation may occur. By January it is possible to see all life stages present on a single tree in some areas. By mid-March, the beetles will disappear, to sheltered sites to hibernate.