Elm Tree Treatment

For trees affected by elm leaf beetle, including the Golden Elm and the Weeping Elm, it is important to employ appropriate treatments at the correct time to achieve long-term protection for your elm tree and avoid major leaf damage and serious overall decline.

About the Elm Leaf Beetle

The elm leaf beetle can defoliate an elm tree in a week if left untreated and poses the greatest threat to the health and wellbeing of the elm tree population in Australia. Some of the elm trees that are susceptible to the elm leaf beetle include the Golden Elm and the Weeping Elm.

The elm leaf beetle is approximately the size of a large grain of rice, appearing dull green in colour early in the season, with the colour becoming more defined as the season progresses.

Adult beetles are free flying but are also known to “hitch a ride” on a vehicle. They move from tree to tree feeding and laying eggs on the undersides of the leaves. Early in the season damage is often noticed on one side of the tree, and this indicates the source of hibernating and emerging beetles.

What damage is caused by the elm leaf beetle?

The most severe damage inflicted by the elm leaf beetle occurs mainly during the larval stages of the insect’s lifecycle, skeletonizing the leaves and destroying the tree’s ability to achieve photosynthesis and produce reserves of energy that carry it through its dormant period.

Damage caused by an adult elm leaf beetle is evidenced by the leaves taking on a ‘shot hole’ appearance – and this damage continues right through the growing season.

Trees can often be defoliated within a very short period of time (in some cases within a week) with high temperatures increasing the speed of the beetle’s metabolism.

What are the treatment options for controlling Elm Leaf Beetle?

The three main treatments for elm leaf beetles are:

• Tree (or trunk) injection – A fast, safe and inconspicuous, all-year-round treatment involving the direct injection of Ema-Ject®, fungicides or both into the actual tree trunk.
• Canopy spraying – Implemented at full leaf expansion (around the 3rd week of October) – not favoured by Elmsavers, but using biologicals.
• Soil injection – Involving injecting an insecticidal solution around the root zone – a treatment option completely phased out by Elmsavers.