ANNAPOLIS, MD (January 15, 2006)
David R. Lance, USDA APHIS PPQ, www.forestryimages.org
In February, 2005, a horntail (a wood boring
wasp) new to the U.S was
discovered by Dr. Richard Hoebeke,
in a September, 2004 forest survey trap sample from Fulton, N.Y.
Identified as Sirex noctilio, it was not only
new to the US, but known to be a serious pest on three other
continents. Since 1985, only eight other adult S. noctilio
had been intercepted by State and federal inspectors with packing
materials from other countries,
but subsequent inspections of surrounding areas never yielded further
specimens. However, an ongoing
delimiting survey of the New York detection has so far turned up 85
adults and larvae from within a 40 mile
radius from the initial find.
Ironically this horntail, S. noctilio is not
considered a primary pest of pines in
its native Europe and Asia, but it has proven to be of major concern in
pine plantations. It is also established in Australia, South Africa and
New Zealand. It
therefore should be able to thrive anywhere in North American where
there are pine forests.
This unusual insect has earned the designation as “Invader of
the Month” for January by the
Maryland Invasive Species Council.
Although many species of Pine (Pinus) are hosts,
Monterey and loblolly appear especially vulnerable.
The concern about this wasp is that loblolly and related species of
“southern pines” are the bread basket of
forestry in southern US. Like many other wood boring insects, S.
noctilio tends to favor stressed trees, but
it also attacks and kills apparently healthy trees as its populations
grow. It has been known to kill up to
80% of the trees in stands of North American pine species grown in
plantations in south America. The main
reason it is such a threat is because as the female horntail inserts
its eggs in trees, it also inoculates
the wood with a fungus, Amylostereum aveolatum. As this fungus grows in
the wood of the tree it serves as
nutritious food for the wasp larvae but it can also rapidly kill the
trees. Unfortunately, the lumber
salvaged from these dead or damaged trees is often used for packing
crates, pallets, and other utility
purposes where lumber suitable for furniture or framing would be too
costly to use. The slow-growing
larvae are difficult to detect before emergence holes appear, and by
that time, the crate or pallet may
have traveled hundreds or thousands of miles to its destination. Once
she emerges, the large female wasp
is a strong flyer (as far as 100 miles!), and infestations in other
countries expand 5-15 miles per year.
This discovery of an infestation in New York State has federal and
concerned and planning to survey more intensively for this exotic pest
in other nearby states. Scientists are looking for parasites and
predators to combat this serious threat; a parasitic nematode being
used in Australia has shown promise. Also, efforts are underway to
develop better lures and trapping methods to detect its presence
earlier in new infestations. Early detection and intervention is the
key to success.
The large “spike-tailed” larvae can mine in wood
for more than a year before emerging as a striking 1-1 1/2 inch (25-40)
mm long, blue-black, winged adults with orange legs. They do not have a
typical wasp’s slender waist. Although there are several
other horntails in our area, any suspicious insect should be caught,
kept and sent to an entomologist for identification. If you find any
insect of concern, contact Dick Bean, entomologist, at the Maryland
Department of Agriculture at 410-841-5920.
For more detailed information about Sirex noctilio, click here.
For more information about other Invasive Species of Concern, visit www.mdinvasivesp.org
photos available electronically on request.