This document summarizes chemical and biological control methods for Ailanthus altissima (tree-of-heaven). It describes a "drill and fill" chemical control method that is effective year-round by drilling holes and injecting glyphosate directly into the trunk. It also describes the naturally occurring biocontrol system of the Ailanthus webworm (Atteva aurea), the Ailanthus mite (Aculops ailanthii), and fungi like Fusarium that work together to kill Ailanthus trees. This system provides a model for developing other native biocontrol systems for invasive species.

1. Chemical and Biological Control
of Ailanthus altissima, the Last
of 3 Presentations

2. Richard Gardner
rtgardner3@yahoo.com
(410) 726-3045

3. ABSTRACT: This is the third and final presentation on
Ailanthus altissima (Tree-of-Heaven). It will show that
Ailanthus altissima is easy to kill by chemical methods
24/7/365. At the same time, over several states and
years, a naturally occurring biocontrol system has been
observed that is effectively killing Ailanthus altissima.
This serves as a model for finding biocontrol systems
for other invasive non-native organisms and ending the
scientifically unsound practice of introducing yet more
non-native organisms to control current and future
problems.

4. Tree Physiology

5. Early in the life of
Ailanthus the main root
makes a right angle turn
that is parallel with the
ground as seen in this
photo and the following.

7. Fluid flow is along a line @ 2” wide
from the injection to the apical
meristems in the roots and
branches.
This was found out by drilling a
hole into the trunk and injecting
50.2% glyphosate then tracking
the death of the leaves and
vascular cambium.
f
l
u
i
d
f
l
o
w
Injection point

8. Injection point

9. The left fork of this trees was
poisoned about 2 weeks
before this photograph.
This and similar experiments
were performed on several
trees.

10. Male trees – notice the single clean peduncles
peduncle
peduncle

11. Female tree – notice the elaborate branching peduncles and seeds.
peduncles
peduncles
with seeds

12. Biocontrol

13. Atteva aurea – the Ailanthus
web worm, super defoliator, taxi
and disease vector.

18. A. aurea, November 19, 2012 on Solidago sp. along Blue Marsh, Berks
County, PA.

20. egg
egg
larva

21. empty pupa shell
egg
larva
larva

29. larvae entering into pupa stage
pupae

31. This is a young tree full of
communal A. aurea webs, a
common sight.
In this location 100% of the
trees of all age groups had A.
aurea webs.
Communal webs

32. Another young tree with
communal webs and disease
as shown by the dead
branches and chlorosis.
chlorosis

35. Some A. aurea adults are apparently overwintering
in central Pennsylvania as evidenced by the adults
found feeding on Solidago species into late fall and
the finding of larvae early after A. altissima goes
into leaf.
This could be caused by basic evolution as the A.
aurea adapts to colder temperatures due to the
availability of a new food source or due to global
warming.
It is most probably a combination of both.

36. The one question I have not been able to
answer is the nectar source for A. aurea before
mid-summer.
I am assuming that the food source is a native
Asteraceae as the later summer food sources I
have seen are Asteraceae family members.

37. Aculops ailanthii – killer of the
young, bringer of disease and
death.

42. Diseased tree with Aculops ailanthii infestation.
Aculops ailanthii and chlorotic
leaves on a mature tree.

43. A. aurea herbivory
A. Ailanthii
mottling of leaves
A. aurea web

44. Fusarium and Verticillium –
the third strike and death blow,
disease strikes hard and fatally.

45. Fungi that infect A. altissima
Fusarium lateritium – lesions
Fusarium oxysporum - wilt
Fusarium solani – lesions and wilt
Verticillium albo-atrum - wilt
Verticillium dahliae - wilt

46. Fusarium lateritium macroconidia

47. Plate with Fusarium from diseased tree

48. Fusarium macroconidia from diseased tree.

49. Fusarium macroconidia from diseased tree.

50. Fusarium micro and macroconidia from diseased tree.

51. Fusarium micro and macroconidia from diseased tree.

52. With Atteva aurea, Aculops
ailanthii and pathogens working
together death is certain.

53. Urbana, MD Community Park, September 2007.

54. The same stand in July 2011.

55. Pine Swamp Road, near Hawk Mountain, Fall 2011

56. Pine Swamp Road, near Hawk Mountain, August 2012.

57. Blue Marsh, August 2012

58. Blue Marsh, December 2012.

59. Compound leaf with A. aurea larvae and A. ailanthii.

60. This is the first biocontrol system I recognized, SGL 106 near
Hawk Mountain, PA.

61. Birds – best for long distances
Moths – best for
medium and short
distances
Wind – best at
short distances
with high mite
and tree
densities
Transport of Aculops ailanthii across landscapes

62. Transport of Aculops ailanthii across landscapes

63. From recent walking it appears that
there is a correlation between the
density and nearness of the nectar
sources adult Atteva aurea feed on
and the amount of disease in a stand
of Ailanthus.

64. The key to finding a native biocontrol
(system) for plant is to find an
organism which is a generalist
herbivore for a family or genus and a
specialist to that family or genus.

65. This means that the biocontrol has a
the genetic ability to switch from one
plant to another and yet will not cause
the extinction of coevolved food
sources.

66. A. aurea larvae eat other Simbouracae
family members, but only eats
members of this family.

67. A. aurea larvae will preferentially eat a
non-coevolved food source because it
does not have the defenses to it that a
coevolved food source has.

68. Hence, an easy meal that is a higher
quality food source (higher energy
return for energy expended) than a
native coevolved one since it spends
less energy dealing with chemical and
physical defenses.

69. At the same time it is embedded in a
system of a mite (A. ailanthii) and
several diseases.

70. Which together interact to cause
control of A. altissima.

71. Unique features of this system:
1. A. altissima is the only food for A. aurea larvae in most of the A.
altissima range
2. A. aurea adults are generalist nectar feeders
3. A. ailanthii is an apparent specialist to A. altissima
4. A. aurea larvae have no other local food sources so the adults
have spread themselves beyond their normal range by following
nectar sources and egg laying sites.
5. A. aurea and A. ailanthii are the vectors for several A. altissima
diseases
6. A. ailanthii apparently hitchhikes between A. altissima trees on
birds and A. aurea.
7. A. aurea appears to evolving to colder temperatures as witnessed
by their presence feeding on goldenrod in central Pennsylvania in
mid-November after frost and freeze.

72. How to develop an Ailanthus
biocontrol system:

73. 1.) Do not apply pesticides to the
surrounding area – herbicides,
insecticides, fungicides, … .

74. 2. Plant a wide variety of native high
nectar flowers nearby so there are
high quality food sources from mid-
spring to first heavy freeze for the
adults to feed on.

75. So far I have found adult Atteva aurea
on daisy-like flowers and at least 2
species of goldenrod from August to
mid-November. I am still not sure
what they feed on from early spring
when the Ailanthus leaves are just
beginning to bloom to mid-August.

76. Chemical Control:
Drill and Fill -
effective 24/7/365

77. This method was developed as a safe
and efficient method for volunteers to
use in contained areas such as a
township park.

78. Bartram Trail on May 31, 2012 of tree injected January 10, 2012.

79. Drill a 3/8” hole through the vascular
cambium every 2” of girth at
comfortable working height.

80. 3/8” drill holes @ every 2” apart

81. Then spray 50.2% glyphosate
(purple cap RoundUp®
) into the
holes with a spray bottle.

82. If done in the summer, within a
week the leaves will begin
wilting and yellowing.

83. Within 2 weeks the leaves will
begin falling.

84. If the method is done in the winter,
there may be a few vestigial leaves
that try to form as it comes out of
dormancy.

85. However, the tree will still be dead
by the end of the summer.

86. One day after injection in July 2011.

87. 8 days after treatment in July 2011.

88. 11 months after treatment, June 2012.

89. Day 0 at another location. I did this “as a volunteer” to test the
robustness of the method.

90. Two weeks after injection.

91. End of summer at same site.

92. Day 0, five trunks with DBH from 8” to 44”.

93. 17 days after injection.

94. Same stand in October, 4 months after injection.

95. Tree injected on January 10, 2012 then felled by Hurricane Sandy,
October 29, 2012. Notice the burrows of ambrosia beetle Euwallacea
validus, (identified by Dr. Matthew T. Kasson) originating in the drill
holes.

96. Small tree injected in June 20 then felled by Hurricane Sandy, October 29,
2012.

101. The three sure signs of tree death are:
1.) no green layer under the bark
when scraped,
2.) white fungi growing around the
outside of the tree and
3.) loose/peeling bark.

102. It is essential that all dead trees
around trails, roads and buildings be
cut down within six months of dying.

103. Several trees poisoned in January and
June 2012 fell in late October with
Hurricane Sandy.

104. Due to its exceptional growth rate
Ailanthus does not develop the
internal structures denser trees
develop which give them strength.

105. Once it dies, the tree falls and
decomposes swiftly.

106. The reason this method works
24/7/365 is that glyphosate is
degraded primarily by microbes and
not metabolized or detoxified by the
tree.

107. During tree dormancy the microbe
population decreases substantially due
to severely slowed fluid flow within
the tree and low environmental
temperatures.

108. As the tree moves out of dormancy
and the sap begins to flow the
glyphosate poisons the tree most likely
by killing the vascular cambium both
ways along the vertical line between
the injection site and the ends of the
roots and stems while also poisoning
the meristem tissue in the roots and
stems.

109. Method advantages:

110. 1.) It does not use sharp blades. This
reduces the potential for injury.

111. 2.) All the materials can be found
relatively inexpensively in most
hardware stores.

112. 3.) Feedback is fast and can be
watched as it develops. The results
begin to show in less than one week
with nearly complete defoliation of
trees in less than three weeks.

113. 4.) This method can be done in the
winter when the amount of brush is
diminished and there are no biting
insects.

114. 5.) Lastly, this method appears to be
robust and may work on other plants
such as Lonicera morrowii, Lonicera
maackii, Broussonetia papyrifera,
Elaeagnus umbellate or other invasive
woody plants.

115. In summary, this is an easy and safe
volunteer friendly method which is
effective in eliminating Ailanthus
altissima in discrete areas such as
parks. At the same time it is usable by
professionals to cheaply remove
Ailanthus from small landscapes with a
minimum of equipment and time.

116. Glyphosate environmental
non-target organism effects

117. Over 24 days there was an experiment
to measure the affect of glyphosate in
dropped leaves on plants, in this case a
lawn grass mixture.

118. Glyphosate in dropped leaves toxicity experiment on grass,
day 0.

119. Glyphosate in dropped leaves toxicity experiment on grass,
day 24.

120. • 16 trays were filled with potting soil and various grass seed mixtures
over the summer. They were then placed under a row of
mature Spruce trees.
• August 15, 2012 several branches were pruned from tree #2 before
injection and the leaves frozen in 1 gallon Ziplock® bags.
• August 15, 2012 50.2% glyphosate was injected into 2 trees, #1 and
#2 through 5/16” x 1-2” holes
• Leaves were collected after they fell, about 1 week later, and stored
in a freezer.
• On August 31 the leaves were then spread across 16 trays of mixed
lawn grass in potting soil as follows:
o 2 trays left untouched, blank control
o 2 trays with water only, water control
o 6 trays with 100 grams leaves picked from trees before
injection with glyphosate
o 6 trays with 100 grams glyphosate leaves
• On September 24, 2012 the experiment was concluded with no
apparent differences between any of the trays.
Experiment Protocol

121. Other application:
Paper mulberry,
Broussonetia
papyrifera, killed by
Drill and Fill to
demonstrate the
method robustness.

122. Future research
1.) determining the food sources of
Atteva aurea in the late spring and the
first half of summer.
2.) growing a biocontrol garden
specific to Atteva aurea and Ailanthus
altissima control.
3.) determining to the family the fungi
that are infecting Ailanthus altissima
and their carriers.

123. The best way of destroying stands of
Ailanthus altissima:
Plant native Asteraceae near the trees
and leave alone.

124. The second best way to deal with
Ailanthus altissima:
1.) Drill and Fill large trees.
2.) Plant native Asteraceae nearby and
leave alone.

125. Ailanthus altissima biocontrol garden.

126. Ailanthus altissima biocontrol garden
2. Aster laevis 1. Asclepias tuberosa
4. Erigeron speciosus 3. Aster novae-angliae
6. Eupatorium perfoliatum 5. Eupatorium maculatum
8. Monarda fistulosa 7. Heliopsis helianthoides
10. Rudbeckia laciniata 9. Rudbeckia hirta
12. Solidago canadensis 11. Rudbeckia triloba
14. Solidago rigida 13. Solidago nemoralis
16. Verbesina alternifolia 15. Solidago speciosa
18. sunflowers 17. Asclepias syriaca
19. Coreopsis 20. Shasta daisy
21. sweet peppers 22. sweet peppers
23. sweet peppers 24. Eu. mac./Cor.
trip./Ech. pur.
25. Collected plants
pasture uphill driveway

127. • originated in the neotropics and migrated north when a new
food source was available – Ailanthus altissima.
• breed from early in the season until hard freeze – no diapause,
this reinforces that they have not had enough time to change
from a warm climate to a temperate species.
• females mate in the morning and then lay eggs in the evening.
• webs are multigenerational with adult females laying eggs on the
webs made by other larvae.
• from egg to adult is @ 21 days.
• adults apparently overwinter at least as far north as central
Pennsylvania.
• adults have at least a two color morphs, standard
orange/black/white and the same with a reddish cast.
• adults are generalist nectar feeders at least in the Asteraceae
family.
Interesting facts about Atteva aurea

128. • larvae eat the young bark as well as leaves of Ailanthus
altissima, but no other plants.
• larvae have several color morphs from black to light brown and
greenish.
• larvae form “tents” before they enter into the pupal stage by
biting mostly through the rachis (mid-vein) of a
compound leaf and letting it drop, then making a web
around the resultant structure.
• aposematism is the primary defense in the same way as
monarch butterflies – bright, colorful and easy to catch
suggesting that there is no need for other defenses.
Ailanthus altissima ingested as a larva probably make the
larvae and adults unpalatable.
• easy to catch and easy to raise.

129. Facebook:
Ailanthusresearch
Biocontrol/

130. Richard Gardner
rtgardner3@yahoo.com
(410) 726-3045