Giant Woodwasp
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Figure 1 |
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Figure 2 |
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Figure 3 |
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Figure 4 |
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Figure 5 |
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Scientific
Name: Urocerus gigas
Common Names: Giant Woodwasp, Banded
Horntail, Greater Horntail
Known
Hosts:
Urocerus gigas attacks 5 or more genera in
the family Pinaceae including Douglas fir (Pseudotsuga),
fir (Abies), larch (Larix), pine (Pinus),
and spruce (Picea). For a complete listing
of hosts see the USDA Mini Risk Assessment for Giant
Woodwasp, Urocerus gigas: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/pra/ugigaspra.pdf
| Key
ID Features and Life Cycle: |
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Adult wasps are
between 10 to 40mm (0.5 to 1.5 inches) long with
a cylindrical body. Adults have a spear-shaped plate
(cornus) at the tail end. |
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Females have a yellow abdomen
with a black stripe in the middle. The female has
an ovipositor on the end of its abdomen for egg-laying.
(Figure 1) |
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Male adults are smaller than
females. The abdomen is yellow at the center with
black at the base and tail end. (Figure 2) |
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In Great Britain adult flight
was observed between June and early October. |
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Females lay up to 350 eggs
after emergence. (Figure 3) |
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Larvae are creamy white, cylindrical
grubs up to 30 mm (1 1/4 inches) long with a dark
spine at the end of the abdomen. (Figure 4) |
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The larval stage usually lasts
for 1-3 years before mature larvae pupate near the
bark surface. |
| Signs
of infestation: |
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Tunnels in the
wood ranging from 15 to 75 cm (6 to 30 inches) in
length that are tightly packed with frass. (Figure
5) |
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Round exit holes 3-8 mm (1/8
to 3/8 inch) in diameter are visible on trees trunk.
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Similar species:
There are 23 native species of siricids in North America.
The following publication provides a key for distinguishing
those species:
NM Schiff. SA Valley, JR LaBonte, and DR Smith. 2006.
Guide to the Siricid Woodwasps of North America.USDA
Forest Service http://www.fs.fed.us/foresthealth/technology/pdfs/GuideSiricidWoodwasps.pdf
Fact sheets and references:
USDA Mini Risk Assessment for Giant Woodwasp, Urocerus
gigas: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/pra/ugigaspra.pdf
Greater horntail wasp (Yellow-horned horntail) - Urocerus
gigas (L.)
From: Kolk A., Starzyk J. R., 1996: The Atlas of Forest
Insect Pests
http://www.forestpests.org/poland/greaterhorn.html
Exotic Pest Information System for North America
http://spfnic.fs.fed.us/exfor/data/pestreports.cfm?pestidval=24&langdisplay=english
last reviewed February 25, 2008 |
