U.S. patent application number 09/847595 was filed with the patent office on 2002-03-21 for biological control of purple loosestrife.
Invention is credited to Becker, Roger L., Farr, David F., Gronwald, John W., Johnson, David R., Katovich, Elizabeth Jean Stamm, Plaisance, Kathryn L., Rossman, Amy Y..
Application Number | 20020034497 09/847595 |
Document ID | / |
Family ID | 22905362 |
Filed Date | 2002-03-21 |
United States Patent
Application |
20020034497 |
Kind Code |
A1 |
Johnson, David R. ; et
al. |
March 21, 2002 |
Biological control of purple loosestrife
Abstract
The present invention provides a novel isolated and purified
Harknessia lythrii. It further provides a mycoherbicidal
composition that is effective in controlling purple loosestrife,
and methods for controlling purple loosestrife.
Inventors: |
Johnson, David R.; (St.
Paul, MN) ; Becker, Roger L.; (Maplewood, MN)
; Katovich, Elizabeth Jean Stamm; (Blaine, MN) ;
Gronwald, John W.; (Shoreview, MN) ; Rossman, Amy
Y.; (Beltsville, MD) ; Plaisance, Kathryn L.;
(Falken Heights, MN) ; Farr, David F.;
(Beltsville, MN) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG, WOESSNER & KLUTH, P.A.
P.O. BOX 2938
MINNEAPOLIS
MN
55402
US
|
Family ID: |
22905362 |
Appl. No.: |
09/847595 |
Filed: |
May 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09847595 |
May 2, 2001 |
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09240160 |
Jan 29, 1999 |
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6268203 |
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Current U.S.
Class: |
424/93.5 ;
424/405 |
Current CPC
Class: |
A01N 63/30 20200101;
C12N 1/14 20130101; A01N 63/30 20200101; A01N 2300/00 20130101;
A01N 63/30 20200101; A01N 2300/00 20130101; A01N 63/30 20200101;
A01N 63/30 20200101; A01N 63/14 20200101 |
Class at
Publication: |
424/93.5 ;
424/405 |
International
Class: |
A01N 063/00; A01N
063/04; A01N 065/00; A01N 025/00 |
Claims
What is claimed is:
1. An isolated and purified Harknessia lythrii fungus.
2. The fungus of claim 1, wherein the Harknessia lythrii was
isolated from cultivated plant material of the genus Lythrum.
3. The fungus of claim 1, wherein the Harknessia lythrii is culture
deposit ATCC no. PTA-2756.
4. An herbicidal composition comprising an effective amount of an
isolated and purified Harknessia lythrii that effects control of
purple loosestrife (Lythrum salicaria), and a carrier.
5. The herbicidal composition of claim 4, wherein the Harknessia
lythrii is culture deposit ATCC no. PTA-2756.
6. The herbicidal composition of claim 4, further comprising an
effective amount of at least one additional fungus to form a fungal
composite.
7. The herbicidal composition of claim 4, further comprising
Coniella frugarei.
9. The herbicidal composition of claim 4, wherein the carrier
comprises diatomaceous earth, alginate or clay.
10. The herbicidal composition of claim 4, wherein the carrier is a
liquid carrier.
11. The herbicidal composition of claim 4, wherein the carrier is
an adjuvant.
12. The herbicidal composition of claim 4, further comprising at
least one adjuvant.
13. The herbicidal composition of claim 12, wherein at least one
adjuvant is an effective plant-tissue penetrating adjuvant.
14. The herbicidal composition of claim 12, wherein at least one
adjuvant is water-miscible or water-dispersable.
15. The herbicidal composition of claim 12, wherein at least one
adjuvant is a methylated seed oil.
16. The herbicidal composition of claim 4, wherein the Harknessia
lythrii is in the spore form.
17. The herbicidal composition of claim 16, wherein the effective
amount of the Harknessia lythrii is in the range of about
1.times.1.sup.2 to about 1.times.10.sup.12 spores per ml.
18. The herbicidal composition of claim 16, wherein the effective
amount of the Harknessia lythrii is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
19. The herbicidal composition of claim 16, wherein the effective
amount of the Harknessia lythrii is in the range of about
1.times.10.sup.5 to about 1.times.10.sup.8 spores per ml.
20. The herbicidal composition of claim 6, wherein the fungal
composite is in the spore form.
21. The herbicidal composition of claim 20, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.2 to about 1.times.10.sup.12 spores per ml.
22. The herbicidal composition of claim 20, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
23. The herbicidal composition of claim 20, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.5 to about 1.times.10.sup.8 spores per ml.
24. The herbicidal composition of claim 4, further comprising a
germination activator.
25. The herbicidal composition of claim 24, wherein the germination
activator is a monosaccharide, disaccharide, polysaccharide, amino
acid, peptide, peptone, protein, or inorganic salt.
26. A method for controlling purple loosestrife (Lythrum salicaria)
comprising applying an effective amount of a herbicidal composition
onto a target plant or onto the situs of a target plant, wherein
the herbicidal composition comprises isolated and purified
Harknessia lythrii and a carrier.
27. The method of claim 26, wherein the Harknessia lythrii was
isolated from cultivated plant material of the genus Lythrum.
28. The method of claim 27, wherein the cultivated plant material
is living plant tissue, dead plant residue or soil.
29. The method of claim 26, wherein the Harknessia lythrii is
culture deposit ATCC no. PTA-2756.
30. The method of claim 26, wherein the carrier comprises
diatomaceous earth, alginate or clay.
31. The method of claim 26, wherein the herbicidal composition is a
liquid.
32. The method of claim 26, wherein the carrier is an adjuvant.
33. The method of claim 26, wherein the herbicidal composition
further comprises at least one adjuvant.
34. The method of claim 33, wherein at least one adjuvant is an
effective adjuvant.
35. The method of claim 33, wherein at least one adjuvant is
water-miscible or water-dispersable.
36. The method of claim 33, wherein at least one adjuvant is a
methylated seed oil.
37. The method of claim 26, wherein the Harknessia lythrii is in
the spore form.
38. The method of claim 37, wherein the effective amount of the
Harknessia lythrii is in the range of about 1.times.10.sup.2 to
about 1.times.10.sup.12 spores per ml.
39. The method of claim 37, wherein the effective amount of the
Harknessia lythrii is in the range of about 1.times.10.sup.4 to
about 1.times.10.sup.9 spores per ml.
40. The method of claim 37, wherein the effective amount of the
Harknessia lythrii is in the range of about 1.times.10.sup.5 to
about 1.times.10.sup.8 spores per ml.
41. The method of claim 26, further comprising a germination
activator.
42. The method of claim 41, wherein the germination activator is a
monosaccharide, disaccharide, polysaccharide, amino acid, peptide,
peptone, protein, or inorganic salt.
43. The method of claim 26, wherein the herbicidal composition is
applied at least once.
44. The method of claim 26, wherein the target plant is controlled
for multiple growing seasons.
45. The method of claim 26, further comprising an effective amount
of at least one additional fungus to form a fungal composite.
46. The herbicidal composition of claim 45, further comprising
Coniella frugarei.
47. The herbicidal composition of claim 45, wherein the fungal
composite is in the spore form.
48. The herbicidal composition of claim 47, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.2 to about 1.times.10.sup.12 spores per ml.
49. The herbicidal composition of claim 47, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
50. The herbicidal composition of claim 47, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.5 to about 1.times.10.sup.8 spores per ml.
51. The method of claim 26 further comprising applying a plant
stressing agent to the target plant.
52. The method of claim 5 1, wherein the plant stressing agent is
an insect.
53. The method of claim 52, wherein the insect is Galerucella
calmariensis or Hylobius transversovittatus
54. An herbicidal composition comprising an effective amount of an
isolated and purified Coniella frugarei that effects control of
purple loosestrife (Lythrum salicaria), and a carrier.
55. The herbicidal composition of claim 54, wherein the Coniella
frugarei is culture deposit ATCC no. PTA-2757.
56. The herbicidal composition of claim 54, further comprising an
effective amount of at least one additional fungus to form a fungal
composite.
57. The herbicidal composition of claim 4, wherein the carrier
comprises diatomaceous earth, alginate or clay.
58. The herbicidal composition of claim 54, wherein the carrier is
a liquid carrier.
59. The herbicidal composition of claim 54, wherein the carrier is
an adjuvant.
60. The herbicidal composition of claim 54, further comprising at
least one adjuvant.
61. The herbicidal composition of claim 60, wherein at least one
adjuvant is an effective plant-tissue penetrating adjuvant.
62. The herbicidal composition of claim 60, wherein at least one
adjuvant is water-miscible or water-dispersable.
63. The herbicidal composition of claim 60, wherein at least one
adjuvant is a methylated seed oil.
64. The herbicidal composition of claim 54, wherein the Coniella
frugarei is in the spore form.
65. The herbicidal composition of claim 64, wherein the effective
amount of the Coniella frugarei is in the range of about
1.times.10.sup.2 to about 1.times.10.sup.12 spores per ml.
66. The herbicidal composition of claim 64, wherein the effective
amount of the Coniella frugarei is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
67. The herbicidal composition of claim 64, wherein the effective
amount of the Coniella frugarei is in the range of about
1.times.10.sup.5 to about 1.times.10.sup.8 spores per ml.
68. The herbicidal composition of claim 56, wherein the fungal
composite is in the spore form.
69. The herbicidal composition of claim 68, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.2 to about 1.times.10.sup.12 spores per ml.
70. The herbicidal composition of claim 68, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
71. The herbicidal composition of claim 68, wherein the effective
amount of the fungal composite is in the range of about 1'10.sup.5
to about 1.times.10.sup.8 spores per ml.
72. The herbicidal composition of claim 54, further comprising a
germination activator.
73. The herbicidal composition of claim 72, wherein the germination
activator is a monosaccharide, disaccharide, polysaccharide, amino
acid, peptide, peptone, protein, or inorganic salt.
74. A method for controlling purple loosestrife (Lythrum salicaria)
comprising applying an effective amount of a herbicidal composition
onto a target plant or onto the situs of a target plant, wherein
the herbicidal composition comprises isolated and purified Coniella
frugarei and a carrier.
75. The method of claim 74, wherein the Coniella frugarei was
isolated from cultivated plant material of the genus Lythrum.
76. The method of claim 75, wherein the cultivated plant material
is living plant tissue, dead plant residue or soil.
77. The method of claim 74, wherein the Coniella frugarei is
culture deposit ATCC no. PTA-2757.
78. The method of claim 74, wherein the carrier comprises
diatomaceous earth, alginate or clay.
79. The method of claim 74, wherein the herbicidal composition is a
liquid.
80. The method of claim 74, wherein the carrier is an adjuvant.
81. The method of claim 74, wherein the herbicidal composition
further comprises at least one adjuvant.
82. The method of claim 81, wherein at least one adjuvant is an
effective adjuvant.
83. The method of claim 81, wherein at least one adjuvant is
water-miscible or water-dispersable.
84. The method of claim 81, wherein at least one adjuvant is a
methylated seed oil.
85. The method of claim 74, wherein the Coniella frugarei is in the
spore form.
86. The method of claim 85, wherein the effective amount of the
Coniella frugarei is in the range of about 1.times.10.sup.2 to
about 1.times.10.sup.12 spores per ml.
87. The method of claim 85, wherein the effective amount of the
Coniella frugarei is in the range of about 1.times.10.sup.4 to
about 1.times.10.sup.9 spores per ml.
88. The method of claim 85, wherein the effective amount of the
Coniella frugarei is in the range of about 1.times.10.sup.5 to
about 1.times.10.sup.8 spores per ml.
89. The method of claim 74, further comprising a germination
activator.
90. The method of claim 89, wherein the germination activator is a
monosaccharide, disaccharide, polysaccharide, amino acid, peptide,
peptone, protein, or inorganic salt.
91. The method of claim 74, wherein the herbicidal composition is
applied at least once.
92. The method of claim 74, wherein the target plant is controlled
for multiple growing seasons.
93. The method of claim 74, further comprising an effective amount
of at least one additional fungus to form a fungal composite.
94. The herbicidal composition of claim 93, wherein the fungal
composite is in the spore form.
95. The herbicidal composition of claim 94, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.2 to about 1.times.10.sup.12 spores per ml.
96. The herbicidal composition of claim 94, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml.
97. The herbicidal composition of claim 94, wherein the effective
amount of the fungal composite is in the range of about
1.times.10.sup.5 to about 1.times.10.sup.8 spores per ml.
98. The method of claim 74, further comprising applying a plant
stressing agent to the target plant.
99. The method of claim 98, wherein the plant stressing agent is an
insect.
100. The method of claim 99, wherein the insect is Galerucella
calmariensis or Hylobius transversovittatus
Description
PRIORITY OF INVENTION
[0001] This application claims priority to U.S. application No.
09/240,160, filed Jan. 29, 1999 which application is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] Purple loosestrife (Lythrum salicaria) is an introduced
plant that has escaped cultivation to become an aggressive invasive
weed that is spreading rapidly throughout North America. It forms
uniform stands that replace diversified native flora, including
important waterfowl food plants. Because its stands are dense, it
destroys wetlands by reducing water flow and drying out the soil.
Many wetlands in North America have major infestations of purple
loosestrife. It has no natural enemies on the continent, neither
native herbivores nor pathogens, that presently suppress invasive
populations of purple loosestrife. Further, its growth is so dense
that most wetland wildlife cannot use it as habitat. Moreover, it
is not a preferred food for native animals in North America.
[0003] A number of characteristics have enabled purple loosestrife
to become a problem. A single, mature plant can produce 2.5-million
seeds annually. Established plants grow more than 2 meters tall
with 30-50 stems forming wide crowns that dominate a plant canopy.
Also, a strong rootstock serves as a storage organ providing
resources for spring growth and regrowth if the above-ground shoots
are destroyed. R. F. Nyvall, Mycologia, 87:501-506 (1995).
[0004] The U.S. Department of Natural Resources as well as most
states in the U.S. have declared it a noxious weed and require that
it be controlled. It is also on the Noxious Weed List in Alberta,
Manitoba, and numerous municipalities in Canada. Governmental
agencies have been trying to control the spread of purple
loosestrife by various means including cutting it, pulling it out,
spraying it with herbicides and burning it. Some of the control
methods make the situation worse by killing surrounding plants so
the purple loosestrife seedlings have no competition. For example,
the seemingly obvious solution of pulling it up by the roots does
not work. The whole root mass must be removed, causing extensive
disturbance to the soil, and creating the very habitat in which
this plant thrives. Also, all of the plant must be removed, because
it can regenerate from a tiny piece of crown, stalk or leaf buds.
Chemical herbicides such as ROUNDUP.RTM. or RODEO.RTM. are not
desirable because they kill essentially all the wetland plants
since they are not selective for purple loosestrife.
[0005] In addition to there not being acceptable chemical
herbicides for purple loosestrife, environmental concerns make
biological control a potentially attractive alternative to
traditional methods of weed control. Biological control of purple
loosestrife began in Germany in the 1960's. It was found that
certain species of beetles (Galerucella calmariensis, G. pusilla,
and Hylobius transversovittatus) could help control the spread of
the weed. In 1991, the Canadian government approved the
introduction of these predators of purple loosestrife as biological
control agents. In 1992, the United States Department of
Agriculture approved the release of these beetles as biological
control agents in the U.S.
[0006] Unfortunately, it takes quite a long time (3-5 years) for
these beetles to become established in an area, if they become
established at all. Further, even if they become established in an
area, they may not significantly impact purple loosestrife for at
least 2-3 years because the plant is so resilient. Moreover, the
beetles do not always kill the crown of the plant, so they may not
consistently prevent seed production by the plants. The seed bank
of purple loosestrife is viable for approximately nine years.
[0007] To date, no mycoherbicides have been developed from
pathogens of purple loosestrife either in Europe or North America.
In fact, disease symptoms are rarely observed in Europe and no
pathogens have been isolated from purple loosestrife in Europe with
the exception of a nematode Meloidogyne sp. reported to feed on
roots in the former USSR. R. F. Nyvall, Mycologia, 87:501-506
(1995).
[0008] Thus, there remains a continuing need for a means to safely
and effectively control the spread of purple loosestrife. There is
further a long-felt, unresolved need to produce an herbicidal
composition that can be sprayed, or similarly administered, onto
purple loosestrife or other noxious weeds to selectively control
the weeds in environments with mixed populations of useful plants,
such as in a protected wetland.
SUMMARY OF THE INVENTION
[0009] The present invention provides an isolated and purified
Harknessia lythrii fungus. This fungus can be isolated from
cultivated plant material of the genus Lythrum and has been
deposited with the ATCC with accession number PTA-2756.
[0010] The present invention also provides herbicidal composition
containing an effective amount of an isolated and purified
Harknessia lythrii and/or Coniella frugarei that effects control of
purple loosestrife (Lythrum salicaria), and a carrier. The Coniella
frugarei has been deposited with the ATCC with accession number
PTA-2757. The carrier in the herbicidal composition may be
diatomaceous earth, alginate or clay, or may be a liquid carrier.
The carrier may be an adjuvant, or may contain an adjuvant. Such an
adjuvant may be an effective plant-tissue penetrating adjuvant, and
may be water-miscible or water-dispersable. For example, the
adjuvant may be a methylated seed oil. The Harknessia lythrii in
the herbicidal composition may be in the spore form, and may, for
example, be present in the range of about 1.times.10.sup.2 to about
1.times.10.sup.12 spores per ml, in the range of about
1.times.10.sup.4 to about 1.times.10.sup.9 spores per ml, or in the
range of about 1.times.10.sup.5 to about 1.times.10.sup.8 spores
per ml. The herbicidal composition may also contain an effective
amount of at least one additional fungus, such as Coniella
frugarei, which may be in the spore form, to form a fungal
composite. The total quantity of spores in the fungal composite may
be in the ranges given above. The herbicidal composition may also
contain a germination activator, such as a monosaccharide,
disaccharide, polysaccharide, amino acid, peptide, peptone,
protein, or inorganic salt.
[0011] The present invention further provides a method for
controlling purple loosestrife (Lythrum salicaria) by applying an
effective amount of a herbicidal composition onto a target plant or
onto the situs of a target plant, wherein the herbicidal
composition contains isolated and purified Harknessia lythrii and a
carrier, as described above. It may further contain an effective
amount of at least one additional fungus to form a fungal
composite, as described above. The herbicidal composition is
applied at least once, and the target plant may be controlled for
multiple growing seasons., wherein the fungal composite is in the
spore form. The method may also be practiced by additionally
applying a plant stressing agent to the target plant. The plant
stressing agent may be an insect, such as Galerucella calmariensis
or Hylobius transversovittatus
DETAILED DESCRIPTION OF THE FIGURES
[0012] FIGS. 1-14. Harknessia lythrii.
[0013] FIG. 1. Conidiomata produced on PDA.
[0014] FIG. 2. Conidiomata produced on alfalfa stems in distilled
water agar.
[0015] FIG. 3. Conidiomata immersed in leaf of host plant.
[0016] FIG. 4. Longitudinal section of uniloculate conidiomata
produced on host.
[0017] FIG. 5. Longitudinal section of multiloculate conidiomata
produced on PDA.
[0018] FIGS. 6-8. Conidiogenous cells in fluorescence
microscopy.
[0019] FIG. 9. Apical view of conidia showing longitudinal slits in
fluorescence microscopy.
[0020] FIG. 10. Conidia showing basal thickened wall with central
pore in fluorescence microscopy.
[0021] FIG. 11. Median view of conidia.
[0022] FIG. 12. Surface view of conidia showing widely spaced
slits.
[0023] FIG. 13. Germinating conidia.
[0024] FIG. 14. Conidia with an appendage. All from holotype (BPI
747560) or ex-type culture. Scale bars: 1-3, 5=100 .mu.m; 4,
9-14=10 .mu.m; 6-8=5 .mu.m.
[0025] FIGS. 15-17. Harknessia eucalypti. Conidiogenous cells with
developing conidia in fluorescence microscopy. Type specimen (BPI
368192) Scale bars in FIGS. 15-17=10 .mu.m.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Lythrum cultivars were obtained from the Morden Research
Station in Morden, Manitoba and independently from Behnke Nurseries
in Maryland. These cultivars were propagated in the greenhouse and
grown together with other cultivars and weedy lythrum in a
loosestrife nursery. One of the inventors observed that some of the
cultivars growing in the greenhouse were dying from what appeared
to be a plant disease. The sick plants would begin to wilt, and
then completely dry out and die. Most of the sick plants were of
the cultivar, "Morden Gleam", which is a hybrid created from
crossing the cultivar "Morden Pink" (Lythrum virgatum) with the
native, winged loosestrife (L. alatum). The two species of Lythrum
are different species from the weedy purple loosestrife (L.
salicaria). Although the L. virgatum and L. alatum are distinct
species, they are closely related and will occasionally cross to
produce hybrids, as occurred in the creation of the hybrids "Morden
Rose" and "Morden Gleam." Artificial crosses, however, made between
the two species have rarely produced seed that will germinate.
[0027] The inventor gave some of the infected plant material to one
of the other inventors, who isolated a fungal culture from the
cultivars. The inventor then took some of the original fungal
culture and sprayed it onto weedy purple loosestrife plants
(Lythrum salicaria). The inventor was able to reisolate the fungal
culture from the weedy purple loosestrife plants. It was also
observed that weedy purple loosestrife plants developed the same
symptoms as in the "Morden Gleam" plants. Therefore, even though
the fungal culture was initially isolated from a hybrid cross of
two species, L. virgatum and L. alatum, it was able to infect
another closely related, but distinct, species of Lythrum.
[0028] The fungal culture was sent to the U.S. National Fungus
Collections for identification. The culture was identified as two
fungi, Coniella frugarei, and a new species, Harknessia lythrii,
which is discussed and illustrated in Example 6 below. The fungal
mixture that was isolated from the "Morden Gleam" plant hosts was
deposited with the American Type Culture Collection (ATCC), 10801
University Blvd., Manassas, Va. 20110-2209 on accession number
PTA-223 on Jun. 15, 1999. The newly discovered Harknessia lythrii
was deposited with the ATCC on Dec. 5, 2000 and accorded accession
number PTA-2756. Coniella frugarei was deposited with the ATCC on
Dec. 5, 2000 and accorded accession number PTA-2757.
[0029] An isolation procedure that may be employed to obtain the
fungus or fungal mixture involves surface sterilizing the infected
stems or leaves in 70% ethanol for 3-5 minutes, sectioning material
with a sterile scalpel, rinsing the material in sterile distilled
water, and placing the tissue onto potato dextrose agar. The
herbicidal composition can be used in a variety of environments to
control growth of noxious weeds, such as purple loosestrife.
[0030] The inventors developed the herbicidal composition of the
present invention, which is a mixture formed by combining an
effective amount of at least one isolated and purified fungus
specific for noxious weeds with a liquid agricultural carrier. The
novel mycoherbicide can be used effectively in diverse
formulations, including the agronomically acceptable adjuvants and
carriers normally employed for facilitating the dispersion of
active ingredients for agriculture applications, recognizing a
known fact that the dosage, formulations, mode of application of a
chemical agent and other variable may affect its activity in any
given application. The described mycoherbicide can be formulated as
a suspension or dispersion, in aqueous or non-aqueous media, as a
dust, as a wettable powder, as an emulsifiable concentrate, as a
granule, or as any of several other known types of formulations,
depending on the desired mode off application. These herbicide
compositions can be applied as sprays, dusts, or granules directly
to the plant or its situs where herbicidal activity is desired.
[0031] The subject fungus or fungal mixture can be obtained by
conventional culture techniques or from the deposited culture
specimens. To convert it to a form that will facilitate the
preparation of the following described compositions, a slurry can
be prepared that can then be dried onto a primary agronomically
acceptable carrier, e.g., vermiculite, whereby the fungus/fungi is
adsorbed onto the carrier. If desired, the slurry can be used as
the concentrate for the herbicidal composition. The actual
concentration of propagules in the formulated composition is not
particularly critical, and is a function of practical consideration
such as the properties of the vehicle or carrier, and the method of
application. Certain spore concentrations, which are described
herein, however, have been found to be preferred. For purposes of
formulation and application, an "effective amount" is defined to
mean any such quantity of propagules sufficient to infect the
target plant and thereby induce the lesions involved in the lethal
activity described herein.
[0032] The subject material described herein can be applied to a
region to be treated by applying it directly to the soil as
pre-emergence treatment or as post-emergence treatment to plant
foliage, or it can be mixed intimately with the soil. The preferred
mode of treatment is application after emergence of the plant
foliage. The subject materials described herein can, for example,
be applied to soil or plant foliage in amounts of from about 0.1
gallons per acre to 300 gallons per acre, wherein the composition
is at a concentration of about 1.times.10.sup.4 to about
1.times.10.sup.9 spores per ml.
[0033] As used herein, an "herbicidally effective" amount of the
fungal agent is an amount that is sufficient to control the growth
of the target plant or plants. "Controlled" plant growth is
intended to mean the ability of the fungus according to the present
invention to infect its target plant to a degree sufficient to
reduce or prevent the ability of the target weed, such as purple
loosestrife, to detrimentally affect the growth of the surrounding
native or desirable plants. It may kill one or more target plant in
the selected area. However, "controlled" growth does not
necessarily require the complete eradication of all of the target
plants in an area.
[0034] Fungal Agents
[0035] The herbicidal composition of the invention is an effective
herbicidal amount of at least one pathogenic fungal agent specific
for noxious weeds combined with an agricultural carrier. The
noxious weed may be purple loosestrife. The pathogen may be a
fungal mixture, in particular, culture deposit ATCC no. PTA-233, or
may be an individual fungus, in particular, Harknessia lythrii,
ATCC no. PTA-2756, or Coniella fragariae, ATCC no. PTA-2757.
Suitable fungal agents used alone or in combination are those plant
pathogens that are host specific and capable of infecting the host
plant and causing disease that interferes with the plant growth
and/or reproduction. The plant pathogens are preferably those that
selectively infect noxious weeds, such as purple loosestrife,
without affecting other plants such as native wetland plants.
[0036] The method of isolating suitable fungal agents involves
growing the fungus on potato dextrose agar for 10 days and
harvesting spores by scraping the plates in sterile diluted water.
Spores are then diluted to 106 spores/ml, as determined by counting
in a hemacytometer, and sprayed onto plants.
[0037] Suitable Carriers
[0038] The fungal agent is combined with a suitable carrier in an
effective herbicidal concentration. Examples of suitable carriers
include water, fertilizers, oils (petroleum or plant based),
humectants, or combinations thereof. Alternatively, the
agricultural carrier may be a solid, such as diatomaceous earth,
alginate or clay, including granules or suspensions. Alternatively,
the liquid may be modified to yield a physiological solution.
Suitable physiological solution include sodium phosphate, sodium
chloride, sodium acetate, sodium citrate and the like, preferably
in an about 0.001-1M aqueous phosphate buffer. Other suitable
physiological solutions are well known in the art and would include
0.85% sodium chloride. An effective herbicidal amount of the fungal
agent is preferably 10.sup.2 to 10.sup.12 spores/ml, more
preferably 10.sup.4 to 10.sup.9, and most preferably about 10.sup.5
to 10.sup.8 of the liquid medium.
[0039] Adjuvants and Germination Activators
[0040] An adjuvant may be added to the herbicidal composition of
the present invention. The adjuvant provides for relatively low
aqueous surface tension and increased plant tissue penetration. The
adjuvants are also those that are water-miscible or
water-dispersible, easily atomized, capable of being adequately
retained on the foliage of plants, have low phytotoxicity, and
result in a composition with relatively low surface tension.
[0041] The adjuvants useful in the composition of the present
invention are those disclosed in Adjuvants for Herbicides, Weed
Science Society of America, Allen Press, Lawrence, K S, (1982); or
A Guide to Agricultural Spray Adjuvants Used in the United States,
Rev. 5th ed., Thompson Publications, (1998), which are incorporated
by reference herein. The preferred adjuvants are methylated seed
oils. Other types of suitable adjuvants include ampholytic,
cationic, anionic, and nonionic.
[0042] The adjuvant is dispersed in the liquid suspension
containing the fungal agent, to yield the present herbicidal
composition. The adjuvant is present in an effective plant
tissue-penetrating amount that is preferably within the range of
about 0.001% to 10% volume/volume, more preferably about 0.01% to
6% volume/volume, and most preferably about 0. 1% to 4%
volume/volume of the liquid suspension containing the fungal
agent.
[0043] The herbicidal composition may also contain a germination
activator. Examples would be monosaccharides, disaccharides,
polysaccharides, amino acids, peptides, peptones, proteins,
inorganic salts, and other solutes.
[0044] Methods of Forming and Using the Herbicidal Composition
[0045] The herbicidal composition is useful to control weed growth
in a variety of environments, especially wetlands. These
environments generally have a mixed population of plants, for
example, cattail (Typha spp.), beggartick (Bidens spp.),
broad-leaved arrowhead (Sagittaria latifolia), bulrush (Scirpus
spp.) and willow (Salix spp.). The composition is effective against
purple loosestrife without affecting the other wetland plants. The
herbicidal composition is also suitable for application by low
pressure spraying so that large areas of land may be easily
treated.
[0046] The present herbicidal composition is formed by combining an
effective amount of at least one fungal agent with an agricultural
carrier, and optionally with an adjuvant and/or a germination
activator, to form an essentially homogeneous dispersion.
[0047] After the herbicide is formulated, it is applied to the
weed-infested area. The weed population includes purple
loosestrife. Other wetland plants are not inhibited. The herbicidal
mixture may be applied by ground spraying, aerial spraying,
painting or brushing, or by hand or mechanical dispersion,
including but not limited to backpack or other hand held devices,
hydraulic or air nozzles, granular applicators, electrostatic
applicators, controlled droplet applicators (CDA), or ultra-low
volume (ULV) applicators. The herbicidal composition of the present
invention is especially suitable for spraying.
[0048] The herbicidal mixture is applied in single or repeated
applications until weed growth is effectively inhibited. The
conditions leading to effective weed growth inhibition depend, in
part, on the environment. For example, a single application of the
herbicidal mixture may be sufficient or a plurality of application
may be required. The herbicidal composition of the present
invention can be applied to bare ground, plant litter or to plants
of any age to inhibit growth and/or reproduction, including plants
that have flowered or senesced. The herbicidal mixture is applied
at a density sufficient to cover the area where weed growth is
expected to be observed in amounts from about 0.1 gallons per acre
to 300 gallons per acre, wherein the composition is at a
concentration of about 1.times.10.sup.2 to about 1.times.10.sup.12
spores per ml. The concentration may be in the range of 10.sup.9 to
10.sup.9 spores per ml, or in the range of 10.sup.5 to 10.sup.8
spores per ml. Weed growth is effectively inhibited if the majority
of weeds are infected with the fungal agent and exhibit symptoms of
disease.
[0049] The following examples are intended to illustrate but not
limit the invention.
EXAMPLE 1
Treatment of Purple Loosestrife with a Combination of a Fungal
Agent and Galerucella calmariensis
[0050] The fungal agent deposited as ATCC PTA-223 produced in
culture was applied in distilled water with a hand-pump sprayer.
The spray solution was applied at a concentration of
1.3.times.10.sup.6 spores/ml to weedy purple loosestrife plants in
combination with the leaf defoliating beetle, Galerucella
calmariensis. Adult beetles were placed in an un-capped vial. Vials
were placed inside screen cages covering the plants. Beetles
crawled out of vials and onto plants. G. calmariensis is an insect
biological control agent currently being released in Minnesota to
control purple loosestrife. Leaf feeding by the beetle may provide
entry wounds for the fungal agent. After a period of eight days,
the insects were removed by hand from purple loosestrife plants and
the plants were evaluated for fungal disease symptoms. Stem cankers
were found on plants. Ten plants were tested, and all plants with
the fungal agent +dH.sub.2O had cankers and the cankers were
determined to be caused by the fungal agent. On half of the plants
there was no green tissue remaining.
EXAMPLE 2
Field Treatment of Purple Loosestrife with a Fungal Agent
[0051] In another experiment, the inventors sprayed purple
loosestrife with fungal agent ATCC PTA-223 in a wetland at the
Dodge Nature Center in Mendota Heights, Minn. in late July. The
fungal agent was sprayed as a liquid formulation with a backpack
sprayer at a concentration of 1.times.10.sup.6 spores/ml in
combination with 3% AGRI-DEX.RTM. which is manufactured by Helena
Chemical Co., Memphis, Tenn. In one treatment, spores were obtained
from plate culture and in the other treatment, spores were obtained
from shake culture. Plates were prepared for potato dextrose agar
and broth was prepared for potato dextrose broth. The cultures were
grown at room temperature for 10 days, and shake cultures were
shaken on an orbital shaker at 250 RPM. Two, 10 by 10 feet plots
were sprayed for each treatment. Plants were evaluated for presence
of the fungal agent in late August of that same year. The fungal
agent was reisolated from purple loosestrife plants from the plate
culture treatment.
EXAMPLE 3
Greenhouse Treatment of Purple Loosestrife with a Fungal Agent
[0052] A greenhouse study was conducted in which purple loosestrife
seedlings were sprayed with fungal agent ATCC PTA-223 in
combination with different spray additives. Emery 6804 which is
manufactured by Henkel, Cincinnati, Ohio, AGRI-DEX.RTM. and
SOYDEX.RTM. which is manufactured by Helena Chemical Co., Memphis,
Tenn. were used at 3% v/v. Spore concentration was
1.0.times.10.sup.6 spores/ml. Fungal stem cankers developed on
purple loosestrife stems on all treated plants. The greatest
disease severity and incidence occurred on plants treated with
Emery 6804. The controls (not sprayed) did not become infected.
EXAMPLE 4
Treatment of Potted Purple Loosestrife with the Fungal Mixture
[0053] In the spring, 60 perennial purple loosestrife crowns were
planted in pots and allowed to grow. When shoots were from 4 to 8
inches tall, they were treated with one of the following: fungal
mixture ATCC PTA-223 plus Emery 6804 (3% v/v); control plus Emery
6804 (3% v/v); and control (no treatment). Plants were rated for
disease incidence and percent tissue necrosis after one month. At
this time, half of the plants were cut and aboveground biomass
measurements were obtained. These plants were then resprayed when
the shoots were 4 to 8 inches in height for a total of two
treatments per plant. After one month, data was collected as
described above. Plants sprayed one time only were mulched and
overwintered. In the following summer, aboveground biomass was
determined for the overwintered plants (see Table 1).
1TABLE 1 Efficacy of the fungal mixture on purple loosestrife
regrowth dry weights one year after application. Dry Weight
Treatment -g- Control 50.0 Control + Emery 6804 50.7 Control +
Emery 6804 62.1 (2 applications) Fungal Mixture + 8.9 Emery 6804
Fungal Mixture + 23.1 Emery 6804 (2 applications) LSD (0.05)
30.5
[0054] Results of this experiment indicated that plants treated
with the fungal mixture showed disease symptoms and the fungus was
reisolated from disease lesions. Control and control plus adjuvant
treatments did not have disease symptoms. Crown regrowth, from
plants treated two times in the first summer, was reduced as
compared to control plants. Plants overwintered and harvested in
the following summer also had statistically less significant
regrowth as compared to control treatments. This was a significant
result as it showed that crown growth may be impaired after
treatment with the fungal mixture, an important consideration when
trying to control a persistent perennial plant such as purple
loosestrife. Control of regrowth from the crown is critical for
long-term suppression of purple loosestrife.
EXAMPLE 5
Specificity of the Fungal Mixture as a Biological Control Agent
[0055] This experiment was conducted in wetlands located at
Roseville Central Park, Roseville, Minn. In July, plots were
sprayed with Emery 6804 at 3% v/v, and two rates of spores of the
fungal mixture ATCC PTA-223; 1.times.10.sup.6 spores/ml or
2.times.10.sup.6 spores/ml. At the time of spraying plants were
approximately 3 to 5 feet tall and were flowering. After one month,
purple loosestrife plants were rated for disease incidence.
Established purple loosestrife plants had noticeable disease
lesions, which when cultured, were identified as the fungal
mixture. Other wetland plants, such as cattail (Typha spp.),
beggartick (Bidens spp.), broad-leaved arrowhead (Sagittaria
latifolia), bulrush (Scirpus spp.) and willow (Salix spp.) that
were sprayed with the mycoherbicide did not exhibit similar lesions
and the fungal mixture could not be isolated from these species.
Seedling purple loosestrife plants were killed by treatments with
the fungal mixture.
[0056] In the following summer, the plots sprayed the previous
summer were evaluated. Fungal lesions were found on stems of plants
treated in the previous year, and on stems of new growth. When the
lesions were examined, characteristic pycnidia were present
containing spores of the fungal mixture. This experiment showed
that the fungal mixture survived the winter and was able to
re-infect purple loosestrife plants the following summer. This is
an important attribute for a mycoherbicide used for control of
purple loosestrife, as herbicide application costs are very
expensive due to site inaccessibility.
EXAMPLE 6
Identification of Harknessia lythrii on Purple Loosestrife
[0057] Material and Methods
[0058] For microscopic examination material was rehydrated and
mounted in 3% KOH. Conidiomata were sectioned at about 10 .mu.m
thick using a freezing microtome. Sections were mounted in lactic
acid with cotton blue. Observations of microscopic features were
made using a Zeiss Axioplan 2 microscope with both bright-field and
fluorescence illumination. Calcofluor was used as the fluorescent
dye. Photographs and measurements of microscopic features were
taken using a Spot 2 digital camera (Diagnostic Instruments, Inc.,
Sterling Heights, Mixh.) and ImagePro software (Media Cybernetics,
Silver Spring, Md.). The fungus was maintained on Difco Corn Meal
Agar (CM) slants with an alfalfa stem at 4.degree. C. and in water
cultures (Burdsall, Jr. H. H., Dorworth, E. B., Preserving cultures
of wood-decaying Basidiomycotina using sterile distilled water in
cryovials. Mycologia, 86, 275-280 (1994)). To produce and observe
pycnidia in culture the fungus were grown on autoclaved
20-40.times.1-2 mm stems of Medicago (alfalfa) placed on distilled
water agar in petri dishes. For the growth studies, plates of CM
and PDA were inoculated with a 6 mm diam plug of actively growing
mycelium placed at the edge of the plate and grown at 25.degree. C.
in the dark for eight days. Color names and numbers were determined
using Kornerup & Wanscher (1978), Methuen Handbook of Colour
London: Methuen & Co. (243 pp.).
[0059] Taxonomy
[0060] Harknessia lythrii Farr & Rossman, sp. nov. FIGS. 1-14
Conidiomata in hospite uniloculata, globosa 75-90 .mu.m, bruneola,
per rimam elongatam dehiscentia; cellulae conidiogenae basicis
lateralibusque, determinatae vel uno or duo prolieratione,
percurrent, annularibus; conidia brunnea ad atro-brunnea,
subglobosa ad irregulariter ellipsoidea, 10.6-18.5.times.8.9-15.4
.mu.m, unicellulosa, 2-7 aequaliter dispositis, angustis,
longitudinalibus striis, basi breviter eminentia, subinde brevi
appendice. Holotype: UNITED STATES: Minnesota: St. Paul, on Lythrum
salicaria in greenhouse. BPI 747560.
[0061] Conidiomata often obscured by extruded dark-brown conidia;
on host conidiomata immersed to semi-immersed, subcuticular,
scattered, stromatic, uniloculate, globose, 75-90 .mu.m diam,
glabrous, opening by an elongated slit, wall thin, of 2-3 layers of
textura angularis, outer two layers pale brown, outer layer of
cells with somewhat thickened walls; on alfalfa stems, conidiomata
similar to those on host except slightly larger, 90-150 .mu.m diam,
wall of 3-5 layers of textura angularis, outer two layers often of
thick-walled cells; on PDA, conidiomata superficial, appearing
black due to dark-brown due to conidia appearing through pallid
wall, covered with loosely intertwined, hyaline mycelium, scattered
to clustered, stromatic, multiloculate, globose to slightly
elongated, up to 1200 .mu.m diam, each locule opening by an
elongated slit, locular wall of 3-5 layers of textura angularis,
outer layer of pale brown cells with slightly thickened walls.
Conidiophores lacking. Conidiogenous cells lining the base and
sides of the conidiomata, ampulliform, 6-10.times.3.5-6.1 .mu.m,
with a short to elongated apex bearing conidia, once or twice
annellidic following percurrent proliferation of apex, length of
proliferation variable, abscission layer between apex of
conidiogenous cell and base of developing conidia evident in
fluorescent microscopy, base of conidia thickening centripetally
with a cytoplasmic connection remaining as a central pore, evident
in fluorescent microscopy. Conidia brown to dark brown, subglobose
to irregularly ellipsoidal, 10.6-18.5 .mu.m ({overscore (x)}=14.7,
SD=1.5, n=156).times.8.9-15.4 .mu.m ({overscore (x)}=11.6,
SD=1.25), unicellular, wall up to 1.5 .mu.m thick, with 2 to 7
widely spaced, narrow, longitudinal slits extending from the apex
to the base, base truncate, with a short flange, occasionally with
a short basal appendage. Microconidia not seen. On PDA colony 70 cm
diam, white to light yellow (4A5), zonate, zones about 2, 0.7, 3.5
cm from plug, surface mycelium cottony, margin feathery, reverse
pale yellow (4A3); on CM colony 61 cm diam, translucent, no zones,
scattered cottony strands of surface mycelium, margin even.
[0062] Type specimen: UNITED STATES: Minnesota: St. Paul, on
Lythrum salicaria in greenhouse. (HOLOTYPE-BPI 747560; ex-type
culture deposited as ATCC no. PTA-2756). This species and a second
fungus, Coniella fragariae (Oud.) B. C. Sutton (ATCC no. PTA-2757),
were isolated from a greenhouse-grown plant of purple loosestrife
cultivar `Morden gleam` which is a hybrid of Lythrum virgatum L.
and L. alatum Pursh. The cultured isolate of H. lythri was sprayed
on Lythrum salicaria in the greenhouse and produced disease
symptoms as well as sporulating on the leaves. The holotype
specimen was made from the artificially inoculated plant.
[0063] Results
[0064] Harknessia lythri is characterized by conidiomata that are
stromatic locules each opening by an elongated slit (FIGS. 1-5). On
the host and on alfalfa stems in culture, conidiomata of H. lythri
are small, up to 150 .mu.m diam, and uniloculate (FIGS. 2-4) but
become quite large up to 1200 .mu.m diam and multiloculate on agar
alone (FIGS. 1, 5). In H. lythri and H. eucalypti, the type of
Harknessia, conidiophores are lacking and the conidiogenous cells
line the base and sides of the locule (FIGS. 4-5). In H. eucalypti
there are two distinct layers between the conidia attached to the
conidiogenous cell that are evident using fluorescent microscopy
(FIGS. 15-17). One layer is between the conidial body and the
conidial appendage and another between the apex of the
conidiogenous cell and what will become the base of the appendage.
As the conidia mature, the abscission layer closest to the
conidiogenous cell becomes more distinct and eventually becomes the
point of detachment (FIG. 16). This point of detachment determines
the length of the conidial appendage characteristics of many
species of Harknessia. This second abscission layer is not evident
in H. lythri although the conidial development is similar (FIGS.
6-8). As the holoblastic conidia of H. lythri develop, the base of
the conidium thickens centripetally with a cytoplasmic connection
remaining as a central pore (FIG. 10). The conidia of H. lythri are
unicellular and dark-brown (FIGS. 9-14) and have multiple, widely
spaced, narrow longitudinal slits on the conidia that extend from
the apex to the base (FIGS. 9, 12). Although multiple slits are
present, only one tube is formed upon conidial germination (FIG.
13). In H. lythri the basal appendage or frill, typical of species
of Harknessia, may be reduced or almost non-existent although
conidia with an appendage are occasionally seen (FIG. 14).
[0065] Discussion
[0066] Harknessia is a coelomycetous genus that has been well
characterized by Sutton, B. C., The Coelomycetes. Kew, Surrey:
Commonwealth Mycological Institute, p. 696 (1980); and Nag Raj, T.
R., Coelomycetous Anamorphs with Appendage-bearing Conidia.
Waterloo, Ontario: Mycologue Publications, p. 1101 (1993). The
characteristics of Harknessia include having immersed, uniloculate,
pale brown conidiomata of thin-walled, pale brown to hyaline,
small-celled textura angularis (Sutton, B. C., The Coelomycetes.
Kew, Surrey: Commonwealth Mycological Institute, p. 696 (1980)).
The conidiomata of Harknessia lythri on the host and on alfalfa
stems in culture are uniloculate (FIGS. 2-4), however, when
produced on agar alone, they are much larger and multiloculate
(FIGS. 1, 5), suggesting that the conidiomatal size is variable and
that the distinction between uniloculate and multiloculate
conidiomata is not a major one. The increase in the size and wall
thickness of coelomycetous fruiting bodies when produced on agar
substrate has been noted previously by Farr, D. F., Bills, G. F.,
Wojnowicia colluvium sp. nov. isolated from conifer litter.
Mycologia, 87, 518-524 (1995) who emphasize the importance of
producing fruiting bodies on plant material in culture in order to
simulate natural conditions. Although Sutton, B. C., The
Coelomycetes. Kew, Surrey: Commonwealth Mycological Institute, p.
696 (1980) describes the conidiomata of Harknessia as having an
"ostiole central, circular, wide, unspecialized, furfuraceous," Nag
Raj, T. R., Coelomycetous Anamorphs with Appendage-bearing Conidia.
Waterloo, Ontario: Mycologue Publications, p. 1101 (1993) states
that the conidiomata are "lacking an ostiole but dehiscing by
circular or irregular breaks in the apical covering layer" as was
observed in H. lythri.
[0067] Conidiogenesis cells in Harknessia are described as lining
the base and sides of the conidiomata as occurs in H. lythri (FIGS.
4, 5). This feature distinguishes Harknessia from Coniella Hohn., a
coelomycetous genus having conidia similar to those of Harknessia.
In Coniella, the conidiogenesis cells arise from a cushion of
tissue at the base of the conidiomata (Nag Raj, T. R.,
Coelomycetous Anamorphs with Appendage-bearing Conidia. Waterloo,
Ontario: Mycologue Publications, p. 1101 (1993); Sutton, B.C., The
Coelomycetes. Kew, Surrey: Commonwealth Mycological Institute, p.
696 (1980)). In Harknessia conidiophores are generally lacking. The
conidiogenous cells are determinate, often ampulliform, lageniform,
subcylindrical or cylindrical, producing conidia holoblastically,
often proliferating percurrently to produce additional conidia at
the same or higher level (Nag Raj, T. R., Coelomycetous Anamorphs
with Appendage-bearing Conidia. Waterloo, Ontario: Mycologue
Publications, p. 1101 (1993)). The conidiogenous cells of H. lythri
are ampulliform and often extend slightly upon the production of
the second or third conidium (FIGS. 6-8). Species of Harknessia
have smooth, brown, unicellular conidia, sometimes longitudinally
striate, "with a cellular unbranched basal appendage resulting from
the persistent conidiogenous cells" (Sutton, B. C., The
Coelomycetes. Kew, Surrey: Commonwealth Mycological Institute, p.
696 (1980)). The smooth, dark brown, unicellular conidia of H.
lythri are characteristic of Harknessia, although the conidial
ornamentation and lack of a distinct appendage are unusual as
discussed below, distinguishes H. lythri from all other species of
Harknessia.
[0068] The most comprehensive account of the genus Harknessia is
presented by Nag Raj, T. R., Coelomycetous Anamorphs with
Appendage-bearing Conidia. Waterloo, Ontario: Mycologue
Publications, p. 1101 (1993) who described and illustrated 26
species. Ten additional species have been included in the genus,
specifically H. ventricosa Sutton & Hodges on Eucalyptus
(Sutton, B.C., The Coelomycetes. Kew, Surrey: Commonwealth
Mycological Institute, p. 696 (1980)); H. karwarrae Sutton &
Pascoe on Acacia glucoptera (Fabaceae) and H. victoriae Sutton
& Pascoe on Eucalyptus (Sutton, B. C., Pascoe, I., Addenda to
Harknessia (Coelomycetes). Mycol. Res, 92, 431-439 (1989)); H.
eucalyptorum Crous et al. and H. fusiformis Crous et al., both on
Eucalyptus, and H. syzygii Crous et al. on Syzygium coradum
(Myrtaceae) (Crous, P. W., Wingfield, M. J., Nag Raj, T. R.,
Harknessia species occurring in South Africa. Mycologia, 85,
108-118 (1993)); H. leucospermi Crous & L. Viljoen on
Leucospermum (Proteaceae) (Swart, L., Crous, P. W., Denman, S.,
Palm, M. E., Fungi occurring on Proteaceae. I. South African J.
Bot., 64, 137-145 (1998)); H. salvertiana Furlan. & Dianese on
Salvertia convallarioidora and H. qualeae Furlan. & Dianese on
Qualea grandiflora (both hosts in the Vochysiaceae) (Furlanetto,
C., Dianese, J. C., Some coelomycetes from Central Brazil. Mycol.
Res., 102, 19-29 (1998)); and H. tasmaniensis Z. Q. Yuan et al. on
Eucalyptus (Yuan, Z. Q., Wardlaw T., Mohammed, C., Harknessia
species occurring on eucalypt leaves in Tasmania, Australia. Mycol.
Res., 104, 888-892 (2000)). A few additional names exist in
Harknessia but cannot be adequately characterized (Nag Raj, T. R.,
Coelomycetous Anamorphs with Appendage-bearing Conidia. Waterloo,
Ontario: Mycologue Publications, p. 1101 (1993)).
[0069] Species of Harknessia are variable in their conidial
ornamentation ranging from completely smooth to having narrow or
broad, single or multiple, closely spaced or widely spaced
longitudinal striations. Most species of Harknessia have one
longitudinal striation evident as a pallid band of varying widths
or have 2-5 closely spaced, narrow longitudinal striations evident
as a band on only one side of the conidium. Whether these
striations are actually slits has not been determined except in the
case of H. lythri in which germination occurs through this
structure (FIG. 13). One species of Harknessia with unusual
conidial ornamentation is H. gharsei Golatkar in which conidia have
widely spaced, broad, longitudinal bands. A few species of
Harknessia have conidia that lack any striations such as in H.
americana (Mont.) Sutton, H. caudata Ellis & Everh., H.
deightonii Sutton, H. eucrypta (Cooke & Massee) Nag Raj &
DiCosmo, H. fusca (Klebahn) Nag Raj & DiCosmo, H. insueta
Sutton, H. liquidambaris (Berk. & Curt) Nag Raj & DiCosmo
and H. shearii Petrak. Thus, the widely spaced, narrow,
longitudinal slits of H. lythri are unusual and distinct but fall
within the range of conidial ornamentation that occurs among
species of Harknessia.
[0070] In Harknessia lythri the basal appendage on the conidia is
reduced to a basal frill or appendage seen only occasionally (FIG.
14). For several species included in Harknessia such a conidial
appendage is also very short or lacking. These species include H.
guunerae Stevens & Young, in which the appendage is described
as 2-3 .mu.m long, and H. insueta in which the appendage is
described as 1.5 .mu.m long but not illustrated in Sutton, B. C.,
The Coelomycetes. Kew, Surrey: Commonwealth Mycological Institute,
p. 696 (1980). Nag Raj, T. R., Coelomycetous Anamorphs with
Appendage-bearing Conidia. Waterloo, Ontario: Mycologue
Publications, p. 1101 (1993) stated that the appendage of H.
insueta may be up to 2 .mu.m long but is "often gelatinizing and
resulting in a minute marginal frill on the truncate base of the
conidium". Thus, the lack of a basal appendage does not exclude H.
lythri from the genus Harknessia.
[0071] The species of Harknessia most similar to H. lythri are H.
gharsei, H. globosa Sutton and H. hawaiiensis Stevens & Young.
All of these four species have subglobose to broadly ellipsoid
conidia that are about the same size. Harknessia gharsei has
conidia with widely spaced "longitudinal bands of brown and
yellowish-brown" (Nag Raj, T. R., Coelomycetous Anamorphs with
Appendage-bearing Conidia. Waterloo, Ontario: Mycologue
Publications, p. 1101 (1993)), rather than narrow slits as in H.
lythri. Harknessia gharsei is similar to H. lythri in having
conidia each with a very short or non-existent basal appendage,
however, in addition to the differing conidial ornamentation, the
conidia of H. gharsei also have a distinct apiculus. Both H.
globosa and H. hawaiiensis have conidia with narrow longitudinal
striations in a restricted area on only one side of the conidium,
and distinct basal appendages 3-10 .mu.m long.
[0072] Most species of Harknessia occur on the plant host
Eucalyptus (Myrtaceae); other members of the Myrtaceae such as
Melaleuca, Metrosideros, and Syzygium; plant families in the
Myrtales such as the Lythraceae, Melastomataceae and Vochysiaceae;
and plants with leathery or evergreen leaves such as the
Araucariaceae, Ericaceae, Podocarpaceae, Proteaceae, and Smilaceae.
The host for H. lythri, Lythrum salicaria, belongs in the
Lythraceae, Myrtales, and is considered to have affinities with the
Myrtaceae (Heywood, V. H., ed., Flowering Plants of the World. New
York, New York: Mayflower Books, p. 335 (1978)). Most species of
Harknessia are known from only one host plant genus. The exceptions
include H. uromycoides (Speg.) Speg., originally described on
Eucalyptus, now also known from Platylobium obusangulum (Fabaceae)
and Banksia marginata (Proteaceae); H. renispora Swart described on
Melaleuca (Myrtaceae), now reported on other myrtaceous hosts as
well as a non-myrtaceous host, Alyxia buxifolia R. Br.
(Apocynaceae); and H. thujina Ellis & Everh. known only from
members of the Cupressaceae. At present, H. lythri is known only
from Lythrum salicaria. In general members of the genus Harknessia
are known on tropical and semi-tropical plants with exceptions. The
type species, H. eucalypti, was originally described from the San
Francisco area of California; Harknessia americana and H. fuegiana
Speg. are reported from Chile; H. antarctica Speg. is described
from Argentina; H. liquidambaris is reported from New Jersey and
Georgia; H. sudans (Petrak) Nag Raj occurs in France; and H.
thujina is known from New Jersey, Texas and Canada. Although H.
lythri is reported here from Minnesota, the family Lythraceae is
described as having a mainly tropical, sometimes temperate,
distribution (Heywood, V. H., ed., Flowering Plants of the World.
New York, New York: Mayflower Books, p. 335 (1978)).
[0073] All publications, patents and patent documents are
incorporated by reference herein, as though individually
incorporated by reference. The invention has been described with
reference to various specific and preferred embodiments and
techniques. However, it should be understood that many variations
and modifications may be made while remaining within the scope of
the invention.
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