Elm Leaf Beetle Treatment

Elm Leaf Beetle

Elm Leaf beetle (ELB) can defoliate an Elm tree if left untreated.  This is probably the greatest threat to Elms in Australia.

ELB History and Lifecycle

ELB was first identified in Victoria in 1989, near the Mornington Peninsula.  The adult beetles are the size of a grain of rice, a dull green colour early in the season becoming more defined later in the season.

The beetles will hibernate throughout the cooler winter months in dry places such as under tree bark or near adjacent buildings.  In spring, once the weather warms up, they emerge and begin to feed on the new leaf buds and sucker growth.

As the season advances the beetles begin laying eggs the size of sesame seeds.  The eggs look like tiny lemons, and will hatch in 7-10 days dependant on the weather.  The larvae that emerges resemble small black specks.  These larvae feed on the leaf, eating the green matter resulting in ‘skeletonised’ leaves and ‘shot holes’.

This cycle of attack can result in three or four generations attacking the tree in one season and left untreated will result in the tree’s death.


The treatment used by Arborman Tree Solutions is a Direct Injection System involving placing a series of grommets around the trunk through which a measured dose of chemical is injected.  This allows the chemical to be injected into the sapwood from where it is circulated through the leaves within the tree’s crown over 24-48 hours.  The Direct Injection System prevents the need to drill into the tree thereby minimising damage whilst placing the chemical at the site of optimum usage.

Elm Leaf Beetle treatment relies on the beetles eating the leaves to be affected.  It is likely that post treatment you will still see some insect damage however you should also see dead beetles both on the leaves and the ground.

The Direct Injection System is faster acting and safer than soil injection and is targeted only to insects feeding on your tree and doesn’t harm the beneficial insects or other organisms living in the soil.  There is no more drilling, the treatment process is faster, and the treatment uptake by the tree is improved.

Arborman Tree Solutions is excited to be part of this industry leading treatment system.

Common Questions

Will my tree continue to be damaged this season?

Yes, your tree may continue to be damaged however this will reduce over time.  The beetle needs to eat the treated leaves to be affected.  Treatment is managed over multiple seasons and it may take more than one season to noticeably reduce the insect population and foliage damage.  The treatment minimises damage each season by breaking the beetle’s life cycle.

What are the white crystals from around one of the grommets?

It is expected that some grommets will have a small amount of chemical leaking and crystallising around the edges.  The chemical crystallises when exposed to the air and in doing so reduces further leakage.  The concentration of the chemical is such that as much as a 30% leakage would still result in an effective treatment.

How long does it last?

Our program recommends one treatment each spring for two years then treatment every second year to maintain adequate tree protection.

Will it damage my lawn?

No, it will not affect your lawn or adjacent plants.

Is it safe for my kids and pets?

Yes. Stem injection is safer than other methods such as foliar spraying and soil injection.

Are there other things I can do?

Encourage other Elm Tree owners nearby to have their trees treated.  Infestation from neighbouring trees is likely to be your biggest long-term control problem.

Does it always work?

We guarantee the treatment.  Treatment will always result in reduced attack; however, the effectiveness is based on the season.  The earlier in spring the better the control.

If you require further information please contact Arborman Tree Solutions at arborman@arborman.com.au