Pilarska, D., A. Linde, P. Pilarski, G. Georgiev, M. McManus, L. Solter

Release of Entomophthoralean and Microsporidian Fungal Pathogens
for Biological Control of Gypsy Moth in Bulgaria and the United States
Daniela
Andreas
2
Linde ,
Plamen
3
Pilarski ,
Georgi
4
Georgiev ,
5
McManus ,
Michael
6
Solter
Leellen
of Biodiversity and Ecosystem Research, BAS, Sofia, Bulgaria; 2University of Applied Sciences, Eberswalde, Germany; 3Institute of Plant Physiology and Genetics, BAS, Sofia, Bulgaria; 4Forest Research
Institute, BAS, Sofia, Bulgaria; 5 USDA Forest Service, Hamden, CT, USA, 6Illinois Natural History Survey, University of Illinois, Champaign, IL,USA.
Methods
Results
23
E of Greenwic h
Microsporidia Release in Bulgaria:
26
27
28
44
Danube
E
IA
B
R
43
•Both microsporidian species were
collected in the
experimental gypsy moth populations 15 days after release.
Karlovo
44
r
Popovo
N
Ravna gora
43
Black
Sea
Nova Zagora
Striama
A
O
Zvezdets
42
Assenovgrad
MACED
42
e
Riv
Govezhda
Gorna Oriahovitsa
Opletnya
Svoge
Botevgrad
S
•V. disparis-infected third-instar larvae were released in 2008
into low density gypsy moth populations in the Northwest of
Bulgaria (Opletnya), and N. lymantriae-infected larvae were
released in a site in the Southwest (Karlanovo).
25
ROMANIA
NI
Two microsporidian species, Nosema lymantriae and
Vairimorpha disparis were released into naive gypsy moth
populations in Bulgaria and the USA, and the fungal
pathogen Entomophaga maimaiga was released in
Bulgaria. Both microsporidian species were originally
isolated from gypsy moth populations in Bulgaria; E.
maimaiga, which produces epizootics in the U.S., was
traced to an origin in Japan. The microsporidia were
released in Spring 2008 into two low density gypsy moth
populations in Bulgaria and two rising populations in
northern Illinois, USA; the release sites were monitored in
2008, 2009 and 2010. In 2008, N. lymantriae and V.
disparis were recovered from gypsy moth larvae in both
sites in Bulgaria several weeks after release; only N.
lymantriae was recovered in 2009. No infected larvae were
recovered in Illinois sites in 2008 or in 2009 post-release, In
Illinois, epizootics of E. maimaiga, occurred in the gypsy
moth study sites in both years; it is not known if E.
maimaiga competes with microsporidia in host populations.
The microsporidia were released again in the same sites in
the U.S. and Bulgaria in 2010. E. maimaiga was
inoculatively introduced as a classical biological control
agent into six different gypsy moth populations in Bulgaria
during the period 1996-2009. Monitoring studies showed
that the fungus successfully established in nine sites by
2009, several at some distance from a release site, and
one infected larvae was recovered in a microsporidia
release site in 2010. The establishment of E. maimaiga in
Bulgaria has the potential to reduce the use of pesticides
for gypsy moth control, while establishment of
microsporidia in North American gypsy moth populations
would add to the natural enemy complex where gypsy moth
is an introduced pest.
24
Haskovo
U
Abstract
Karlanovo
24
-
Y
50 km
Kirkovo
GREECE
23
R
KE
T
1Institute
1
Pilarska ,
25
26
27
28
Entomophaga maimaiga epizootic in 2005
E. maimaiga recovered
Introduction of E. maimaiga
Vairimorpha disparis released
Nosema lymantriae released
•Of the gypsy moth larvae collected in Karlanovo 3
weeks after the 2008 release, 54.8% were infected
with N. lymantriae. Similarly, in Opletnya, 57.1% were
infected with V. disparis.
Microsporidia Release in Illinois, USA:
•Using the same methods of host rearing, infection and release,
N. lymantriae and V. disparis were released into two rising gypsy
moth populations in northern Illinois, USA in 2008.
• V. disparis was released in Chain ‘O Lakes State Park and N.
lymantriae was released in Volo Bog State Natural Area, both in
McHenry Co., Illinois.
Research Program Goals:
• In 2009, 8.1% of larvae collected in Karlanovo were
infected with N. lymantriae; none of the gypsy moth
larvae recovered from Opletnya were infected with
microsporidia. None of the non-target larvae collected
from the release site in 2008 and 2009 were infected.
•Releases were made in the same sites in 2010, with
33.3% post-release recovery for N. lymantriae and
3.3% for V. disparis.
•In 2005, E. maimaiga epizootics occurred at four
different sites in Bulgaria located 30-70 Km from the
1999-2000 release sites. By 2009, the fungus had
successfully established in nine sites.
•Introduce the microsporidia Nosema lymantriae and
Vairimorpha disparis into North American gypsy moth
populations as classical biological control agents and into
European populations as augmentative controls.
Vairimorpha disparis
infective octospores
Nosema lymantriae
infective spores
•Introduce the fungal pathogen Entomophaga maimaiga
into Bulgarian gypsy moth populations as a classical
biological control agent.
Entomophaga maimaiga release in Bulgaria:
Entomophaga maimaiga was imported from the USA as L. dispar
cadavers containing resting spores of the fungus and introduced
in seven different L. dispar populations in the region of State
Forestries Svoge (Northwest Bulgaria, 1996 and 2001), Karlovo
(Central Bulgaria, 1999), Assenovgrad (South Central Bulgaria,
2001), Stryama (South Central Bulgaria, 2005), Nova Zagora
(Central Bulgaria, 2008), Popovo (Northeast Bulgaria, 2009) and
Gorna Oriahovitsa (Northeast Bulgaria, 2009).
•The microsporidia were released again in the same
sites in 2010. E. maimaiga was again present in
epizootic levels and only one confirmed N. lymantriae
infection was recovered post-release.
•No infected non-target species have been recovered
from the U.S. sites.
The establishment of a new biological control agent, E.
maimaiga, in Bulgaria should facilitate the reduction of
the use of pesticides for control of the native gypsy
moth, while establishment of microsporidia in North
America where gypsy moth is an introduced pest,
would add to the diversity of the natural enemy
complex. We will continue to monitor the release sites
in 2011.
Entomophaga maimaiga
resting spores
Specific Objectives for this Project:
•Release entomopathogens for control of gypsy moth
•Monitor sites for establishment and specificity to gypsy
moth
N. lymantriae and V. disparis were not recovered in
2008 post-release or in 2009 from the release sites in
Illinois, USA. An intensive epizootic of E. maimaiga
occurred in both years.
Gypsy moth larvae killed by
Entomophaga maimaiga
The authors are grateful to D. Takov, N. Cordes, W-F. Huang
and G. Puckett for assistance in the field and laboratory. This
research was supported in part by the National Science Fund of
Bulgaria no. DO-02-282/2008, DFG, USDA Forest Service
agreement no. 06-JV-11232300, US Agric. Expt. Stn. Project
no. ILLU-65-0344, and USDA FS Coop. Agreement no. AG
O1CA-11242343-107.