A simple method for using native and indigenous organisms to eradicate Ailanthus altissima from an area.

1. Richard Gardner
rtgardner3@yahoo.com
410.726.3045
Dec. 10, 2014
Biological control of Ailanthus altissima, Tree-of-Heaven, using native and indigenous organisms
The biological control of Ailanthus altissima can be accomplished using native and indigenous organisms in a systems
approach which bioremediates as it removes the invasive tree from local ecologies. It has been happening for at least
150 years as native organisms such as the native moth Atteva aurea adapted from native neotropical Simaroubaceae
plant species as energy sources to the non-native in that family, Ailanthus altissima.
The system consists of the native moth Atteva aurea, the indigenous eriophyoid mite Aculops ailanthii, native
wildflowers, primarily in the Asteraceae family and various diseases in the Fusarium and Verticillium genera.
At its simplest, building this system involves the planting of native flowers with compact inflorescences such as Solidago
sp., Rudbeckia sp., Verbesinia sp., Clethra sp. and similar to be nectar sources for adult A. aurea. Once these nectar
producing flowers are in place near stands of Ailanthus, adult A. aurea, the key to this system, are given a food source
near their egg laying site/food source for their offspring. Locally, Asteraceae family members have been especially
noticeable as nectaries for A. aurea adults.
What I have seen while doing field research along Blue Marsh Lake in Berks County is multifaceted. The larvae of the
native moth A. aurea feed exclusively on Ailanthus. Adults are generalist nectar feeders which use a wide variety of
Asteraceae flowers as food sources. In particular I see A. aurea adults feeding on Verbesinia alternifolia, Rudbeckia
laciniata and various Solidago sp. close to stands of Ailanthus. The nearby Ailanthus trees are often full, to the point of
overwhelmed, with community webs containing A. aurea eggs, larvae and pupae. By late summer the Ailanthus trees
are often completed defoliated. At the same time, throughout the summer I see claw shaped and other deformed
leaves on nearby Ailanthus trees which mean that they are heavily infested by Aculops ailanthii. Other trees in the
vicinity are severely sick or obviously dying with chlorotic yellowing leaves, bare branches and peeling bark. Taken
together, this points to an active system which is slowly eradicating Ailanthus from that area.
From my observations, my understanding is that A. aurea larvae exclusively eat Ailanthus leaves and young stems. They
prefer the softest plant parts available, but will adapt to harder parts such as mature leaves as the softer food sources
are consumed. The adults are generalist nectarivores which prefer to eat efficiently, i.e. flowers with compact
inflorescences. Since A. aurea is originally a neo-tropical species it produces continual generations of offspring from late
spring to late fall as it has not yet developed a diapause stage. This means that as summer progress there is a
logarithmic population increase of the moth. Each generation i s @ 4 weeks from egg to egg. Once a generation starts
producing webs, subsequent generations will use and expand those webs resulting in the defoliation of the tree.
As A. aurea larvae are eating Ailanthus leaves the eriophyoid mite A. ailanthii is sucking the life out of the leaves. These
gall mites are often transported between trees by wind, but more effectively by using A. aurea as a taxi, phoretic
transport. Once on a tree, they will overwinter in the bud scales ready to continue feeding on the fluids in the leaves in
the spring. Claw shaped or otherwise deformed leaves are a sure sign of A. ailanthii infestation. Mite and moth
infestation often occur in the same stands and on the same tree which strengthens the probability of phoretic transport
by the mite on the moth.
Both A. aurea and A. ailanthii carry pathogens such as Fusarium oxysporum and Verticillium nonalfalfae which kill
Ailanthus trees. The pathogens are ingested while feeding. A. aurea ingests the pathogens while in the larvae stage. As
adults they spread the pathogens either through droppings on leaves and webs or as a coating on its eggs during
ovipositing. As the larvae feed wounds are created in the leaves and stems which allow the pathogens to enter and
infect the tree. I assume that at the same time, because A. ailanthii feeds by sucking plant juices, when it moves from an

2. infected to tree to an uninfected one it will transfer pathogens to the uninfected tree. Since Ailanthus often has root
grafts connecting the trees in a stand, once an infection starts in one tree, it can spread through a whole stand.
To summarize, the best biological way of eliminating a stand of Ailanthus altissima is to plant a wide variety of native
wildflowers from the Asteraceae family to attract adult A. aurea. As the warm season progresses from summer to fall,
different members of this family bloom in succession. By thus ensuring a steady food supply for Atteva aurea adults
there is a greater probability of attracting the adult moths. This leads to egg laying on Ailanthus with the resultant
larvae feeding on and defoliating Ailanthus. With higher densities of A. aurea adults, there will be a greater probability
of Aculops ailanthii infestation. With both A. aurea and A. ailanthii present the possibility of pathogen infection leading
to tree death increases significantly. With local native wildflowers already present, there is little room for non-native
invasive plants to take hold as Ailanthus trees are eliminated. Natural native plant succession will proceed from this
point.
Figure 1 Atteva aurea

3. Figure 2 Aculops ailanthii infested leaves
Figure 3 Chlorotic leaves with Aculops ailanthii present