New Pest Response Guidelines - aphis - US Department of Agriculture

Pest Information
Economic Impact
In the United States, the populations of Scots pine and other potential
coniferous host species of Dendrolimus are probably more vulnerable to attack
than those in Europe and Asia because they have not been exposed and have
probably not evolved natural plant defense mechanisms to these pests. Scots
pine, the PTL primary host, and Douglas-Fir (Pseudotsuga menziesii), are two
of the most popular species of conifers used for Christmas trees, an industry
that in the United States has an estimated value of $506 million USD per year
(USDA-NASS, 2009). Christmas tree production is also important in other
states like Wisconsin, Pennsylvania, Washington and Michigan. The
establishment of any invasive Dendrolimus spp.in the United States would
therefore represent a high risk to this industry. Other coniferous species in the
United States with significant commercial value for the production of timber
and pulp that can also be severely affected include ponderosa pine (P.
ponderosa), lodgepole pine (P. contorta), fir (Abies spp.), spruce (Picea spp.),
pinyon pines (several species including P. cembroides, P. orizabensis and P.
edulis) and junipers (Juniperus spp.) in the west coast and, longleaf (P.
palustris), shortleaf (P. echinata), slash pine (P. elliottii) and loblolly pine (P.
taeda) in the east coast (National Atlas, 2000).
Affected trees are also more vulnerable to the attack of other forest pests. Trees
that recover from the extensive defoliation caused by the larval feeding have a
reduced growth and weak natural defenses, making them more susceptible to
attack by secondary pests like wood borers including Acanthocinus
carinulatus, Ips typographus, I. subelongatus, Melanophila guttulata,
Monochamus galloprovincialis, M. urussovi, M. sutor, Phaenops cyanae,
Scolytus morawitzi, and Xylotrechus altaicus (Ciesla, 2004; EPPO, 2005; Fei
et al., 2008; Ma et al., 1998 ). Recovery of damaged trees can take several
years and depends on the severity of the damage, particularly damage to the
crown and weather conditions (Sliwa and Cichowski, 1975). In severely
affected areas, the increase in the number of defoliated and dead trees results in
higher risks of forest fires (Baranchikov, 1997; Ciesla, 2004; Orlinskii, 2000).
The introduction and establishment of Dendrolimus moths in the United States
could also have a negative impact on domestic and international trading.
Exports of wood and wood products from the United States would have to be
subjected to additional quarantine regulations and treated to prevent the spread
of Dendrolimus moths to other countries where they are absent.
Forests in states and national parks in the western United States are primarily
composed of coniferous tree species with pine trees alone covering an
estimated 13.8% of the total forest area (CAPS, 2008). High defoliation during
2-38 Dendrolimus Pine Moths 12/2012-01