A New Thrips Pest
Chirothrips manicatus:
infesting grasses in the Willamette Valley in Oregon
Alexzandra McKinnis
Dr. Sujaya Rao
Grass: a Diversity of Uses
http://www.coleenanded.com/Nav.aspx/Page=%2fListNow%2fDefault.aspx%2fPageID%3d104742
http://eecs.oregonstate.edu/advantage/slideshow-corvallis/04.html
http://www.endex.com/
Grass Seed Industry in
Oregon
 95% grass seed in
the U.S
 3rd highest
commodity
 $330,000,000/yr
http://forages.oregonstate.edu/is/tfis/chapter/Chapter13/images/Image_ch13_Fig.22.jpg
www.ohwy.com/ or/d/deancrke.htm
Thrips - Thysanoptera
Alex Wild © 2004 http://www.myrmecos.net/insects/Thrips1.html
http://www.ento.csiro.au/aicn/name_c/a_905.htm
http://www.graphicscience.com.au/Gallery/Insect%20Pests/PestsPic22.htm
http://highplainsipm.org/HpIPMImage/Images/1006/sm/IMG0075.jpg
The Life Cycle of
Chirothrips manicatus
1. Female thrips
emerges and lays
egg in fertilized
grass flower
5. Female
overwinters in seed
hull
2. Egg hatches,
larva consumes
the seed as it
develops
4. Adult develops
from pupa
3. Larva pupates
inside seed hull
www. bmi.net/roseguy/_gbthrips.html
Immature stages of
C. manicatus
History of
C. manicatus
 Orchardgrass in
New Zealand
 Suspected to cause
declining yields
 Orchardgrass has
large seeds
A. Peeters http://www.fao.org/ag/AGP/AGPC/doc/Gallery/pictures/dactglo/dactglo.htm
Bentgrass!
 Decrease yields by 5.1%
 $23,000 loss
http://forages.oregonstate.edu/organizations/seed/osc/brochures/bentgrass.html
http://www.nn.net/golf/Turnberry.htm
http://herbarium.biology.colostate.edu/slides/agrostis_stolonifera.html
Detection is Challenging
Questions
 Host range of C.
manicatus
 Infestation Level
Host Range of
C. manicatus
 Host survey
http://biology.smsu.edu/Herbarium/Plants%20of%20the%20I
nterior%20Highlands/Flowers/Dactylis%20glomerata.jpg
Orchardgrass
http://bellquel.scuole.bo.it/scuole/serpieri/erbario/immagini%20erbacee%20spontanee/Gramina
cee/ estuca%20arundinacea.htm
Fine Fescue
Tall Fescue
http://www.flogaus-faust.de/e/lolipere.htm
Perennial
Ryegrass
http://www.vetigastropoda.com/SNAP/themes/reproduction.html
Annual
Ryegrass
Seed Size
Incredible variation!
Methods
 Survey: 3 fields for
each host
 Sample: 200 panicles
 Examine: 1000 seeds
Results: Host Range
Grass
Thrips
Orchardgrass
Present
Fine fescue
Present
Tall Fescue
Not detected
Annual Ryegrass
Present
Perennial Ryegrass
Present
Bentgrass
Present
Diversity of Hosts
Orchardgrass
Fine Fescue
Annual Ryegrass
Perennial Ryegrass
Results: Level of
Infestation
Infestation Level of Willamete Valley Seed Crops
2
1.5
1
0.5
Be
nt
gr
as
s
Fe
sc
ue
Fi
ne
as
s
ye
gr
An
nu
al
R
R
ni
al
Pe
rre
rd
ch
ar
dg
r
as
s
ye
gr
as
s
0
O
Percent Infested
2.5
Only One Species?
Future Research
 Investigate:
 Native grasses
 Detection techniques
 Host impacts on pest
 Impacts of field burning
Impacts on Native
Grasses
 Host survey
Roemer’s Fescue
Native Red Fescue
Spike Bentgrass
American Slough
Grass
 Blue Wildrye




 Infestation level
http://depts.washington.edu/propplnt/Plants/Festuca%20idahoensis%20subsp_files/image002.jpg
Detection Techniques
 Visual inspection under a microscope
(current)
 X-ray
 Staining
 Mass comparison
 Vibration
 Water
 Heat
http://www.absoluteclarity.com/Imports.htm
Impacts of the Host on
C. manicatus
 Size comparison
 host seed vs. thrips
Bentgrass
Fine Fescue
Orchardgrass
Tall Fescue
Perennial
Ryegrass
Annual
Ryegrass
The Life Cycle of
Chirothrips manicatus
1. Female thrips
emerges and lays
egg in fertilized
grass flower
5. Female
overwinters
in seed hull
4. Adult develops
from pupa
2. Egg hatches,
larva consumes
the seed as it
develops
3. Larva pupates
inside seed hull
www. bmi.net/roseguy/_gbthrips.html
Impacts of Field Burning
 Population comparison
 Burned vs. unburned
 3 fields
 200 panicles
http://web.engr.oregonstate.edu/~quinn/field.html
Acknowledgements
Howard Hughes Medical Institute
Dr. Sujaya Rao
Dr. Kevin Ahern
Dr. Stephen Alderman, USDA
Barbara Matson, USDA
Dr. Richard Halse, OSU
Dr. Sabry Elias, OSU