Adult beetles hibernate in winter in sheltered places. As temperatures rise in spring, the beetles emerge and begin feeding on Elm leaves. This feeding is indicated by shot hole damage and it generally begins in late October.

In early November the beetles begin to lay small clusters of eggs, generally on the underside of the leaves. This can continue into January.

Within 7 – 10 days the eggs hatch into small black larvae. The larvae go through three stages called ‘instars’. Each instar eats progressively more than the instar before. Larvae may be found from late November until mid February.

When the larvae have completed their development, they crawl down the trunk of the tree to pupate (form a small yellow ‘cocoon’). This process starts in mid December and can continue until early March.

Adult beetles emerge about 10 days after pupation and begin feeding for a few weeks prior to commencing hibernation from late March. Adults hibernate in dry areas such as sheds, houses, wood piles and cars. In Victoria there is generally only one life cycle per year although studies have found that sometimes there is a second life cycle. At times the second life cycles may not go beyond the larval stage, however this can cause considerable damage to trees late in the season.