BEETLE BATTLE INTELLIGENCE

Xanthogaleruca luteola, commonly known as the elm-leaf beetle, is native to Europe but invasive in other parts of the world. They were accidentally introduced to North America and Australia, and are now widespread serious pests here.

Hosts are known to include English, Scots, American, Siberian and grafted Chinese elms, as well as hybrids such as Ulmus glabra 'Lutescens', the Golden Elm, of which there are 3 cultivars (cv).

In Australia, there are few natural enemies, but are known to be prey to lady beetles and shield (assassin) bugs.

Guy O'Donnell discovered and notified Biosecurity after finding the mother tree in Malvern, SA in December 2011. In 3 years it had spread to every suburb across the Adelaide metropolitan area.

By 2015 it was endemic across South Australia by hitching a lift on vehicles and people.

Concurrently, it spread across NSW and as far north as Armidale by 2020. It is now endemic wherever elms grow, numbers growing in seasonal cycles.

Apologies to Dr Suess.

eggs

Up to 30 tiny yellow eggs are typically laid on the leaf underside in October in 2 or 3 rows are up to 8mm long.

larvae instars

First generation larvae called instars, newly hatched, 1 or 2mm long (with empty egg cases)

larvae

Third stage larvae decended from the tree by falling off the leaves or crawling down the trunk. They congregate by producing a chemical attractant ( a pheromone) as shown.

pupae

Lavae curl up and transform into 5 mm long yellow disc shaped pupae at the base of the tree

beetles

Hatching in December, the beetles fly up to the tree and those surrounding to begin eating elm leaves

Elm Beetle Life Cycle

beetle amore..

Beetles mate after coming out of winter hibernation. The pair, in this case, is less than a season old.

death for breakfast - dead beetles

These beeles have died on ingesting elm leaves of a tree injected with Silvashield, a tree injectable systemic insecticide. The central nervous system of the beetle is interupted and typically the hard wing cover (elytra) is raised in death.

Our Control Method

injecting elms

(long term treatment)

One treatment last 4 growth seasons and often into the 5th using microscopic amounts. Longer 5 and 6 year protection periods can be provided.

somethng to do till we arrive

Tape a short term adhesive and keep replacing it every 3 days. It catches larvae as they migrate (from November onwards). Don't leave the tape on the tree long term as larvae puoate under it and the tape blocks pores in the bark

Fungal infection caused by contaminated drill. Tree will not grow over plastic plug.

how we differ

exacting standards

All equipment is sterilised to prevent the transmission of Bacterial Slime flux (Pectobacterium carotovorum) and parasitic decay fungi.
All drill holes are made 3.5 mm and are sterile filled. Leaving them open allows the ingress of parasitic wood decay fungal and bacterial spores.
No plastic plugs are used in the process as it makes a large 6-7mm hole in trunk and the tree reacts negatively to their presence when left to block drill holes
The tree injectable insecticide Silvashield (from Bayer) is used. It is registered and approved by the APVMA for an effective treatment for elm leaf beetle.

minimum impact on non-target species

NO soil injection or foliage spraying with insecticide as these methods have a major impact on many species of invertebrates (including bees) and upset the ecological balance in the soil
NO bees are harmed through our methods as all the elm species we inject are wind pollenated

training and experience

Consulting and practicing arborist for over 40 years.
Qualifications in Botany with post graduate studies in Viticulture and Oenology

longer term protection

Most arborists treat every 2 years. Following experimental trials, we successfully treat every 4-5 years using tiny holes and as few holes as possible. This reduces damage to your trees by 50%.