Elm Leaf Beetles

03 February, 2008

Question: This little beetle was sitting next to me on the tram this morning. What is it and where was it going?

Answer: The beetle on your tram was an Elm Leaf Beetle, Xanthogaleruca luteola.

Elm Leaf Beetle, Pyrrhalta luteola

An Elm Leaf Beetle, Xanthogaleruca luteola
Photographer: Alan Henderson, Source: Museum Victoria

One of the beautiful features of Melbourne is the avenues of planted trees, many of them featuring introduced species such as the Elms. Many Elm populations around the world have been devastated by Dutch Elm disease; at present this disease is absent from Australia but other threats to Melbourne’s beautiful, mature Elm trees include drought and the introduced Elm Leaf Beetle.

The Elm Leaf Beetle is a species of beetle from Europe; it was found on Victoria’s Mornington Peninsula in 1989 and has now spread to Melbourne and regional areas. It causes damage to Elm trees in its larval and adult form. The beetles are not borers but they cause damage to the tree by feeding on the leaves. In severe cases they can cause defoliation of the tree.

Elm Leaf Beetles are around 6 mm in length. They are attractive mainly yellow beetles with black stripes on their elytra (protective wing covers) and black spots on their thorax. As adults, Elm Leaf Beetles eat distinctive ‘shot-holes’ in the leaves. The larvae ‘skeletonise’ the leaves by consuming everything but the veins of the leaves.

Once the larvae are ready to pupate they move down the trunk of the tree to pupate in the soil or in any crevices in the bark of the lower trunk. One control method is to trap the larvae as they move down the tree trunk between mid December and February.

When the weather starts to get cooler the adult beetles can over-winter in peoples’ homes or cars. In spring, when the weather starts to warm up again, they re-emerge and start looking for Elm trees again.

People are often concerned that they have borers in their homes when they find large numbers of these beetles emerging in their homes. However, Elm Leaf Beetles will cause no problems to peoples’ homes; they just use them to stay warm and secure over winter.

Elm Leaf Beetles are often brought into the Melbourne Museum Discovery Centre for identification. I expect the beetle entered your tram accidentally. Or perhaps it came in on purpose - trams are certainly a wonderful way to travel to the many elm-lined streets in Melbourne.

Comments (8)

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Louise Boutard 17 November, 2011 14:56
We have a large amount of these little beetles around our home as we are surrounded by very old elm trees.The Council has sprayed them in the past. Is there an environmentally friendly way I can protect the young weeping elm in our yard?
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Louise Boutard 17 November, 2011 14:58
Thank You for providing the above information. It has been very useful.
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Discovery Centre 1 December, 2011 15:00
Hi Louise, you can probably find some organic means of pest control of these beetles by searching online for green or organic pest control. This link also has some information on reducing numbers by wrapping sticky tape around the tree.
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Anne 27 October, 2013 12:55
This is our third year of these little pests! Our tree is 21 years old. This year I have been squashing every beetle I see and can reach. I figured they might only fly to the lower branches first. I think I've killed about 250 so far. I look before work and in the afternoons. I'll do the banding as well. Last year our tree nearly died.
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Tim Jordan 17 January, 2015 11:25
Saw one of these today in Carlton. I'm positive on the markings and description except the size... 6mm in length? No, 20mm easy! It was foraging briefly amongst flowers before I spotted it. It's sound gave away its position. At first thought it may have been a wasp or bumble bee but had a deeper resonance. Flew away to the elm trees but not before I had a good look at it.
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Discovery Centre 17 January, 2015 11:38
Hi Tim, if you see it or a similar individual again and can get an image we'd be happy to have a look, you can send the image to discoverycentre@museum.vic.gov.au It does sound much larger than the elm leaf beetle is meant to be.  
Lumir Cech 25 February, 2015 15:56
I found a cheap and very effective way to reduce the number of elm tree grubs and beetles - without using any toxic chemicals. All you need is few rolls of 50mm (or similar) clear packaging tape. Wrap one strip of tape tight around either the trunk (if practical) or all individual lower branches with the glue facing in (stuck to the bark) and then another layer over the top with the glue facing outward. This only works during the grub migration down the trunk (Jan-Feb). The grubs get stuck to the tape and can't get across it. Replace the tape daily and you'll reduce the numbers greatly. I trap at least 2 thousand per day like this of a fairly big (10m) tree. They're mostly grubs coming down, but some immature beetles get caught on the way up the trunk at the same time. I also have couple of small trees (2m) and spray those with pyretherin every now and then.
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Calochilus 19 March, 2015 23:41
These have defoliated nearly all Elms in Canberra leaving Siberian Elm til last
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