New Pest Response Guidelines - aphis - US Department of Agriculture

Pest Information
percentage (7%) suffered permanent damage including ankyloses of finger
joints or deformed auricles (Diaz, 2005).
Sunlight intensity and therefore, soil temperature increase at the forest floor
promoting the growth of plant species commonly found at high densities at the
forest edges in unaffected forests. Averensky (2010) summarized this effect
between intact and silk moth affected larch forest (Table 2-7 on page 2-42).
Table 2-7 Change in growth conditions in silk moth affected Larix forests 1
Larix forest
Light
intensity,
thousand
luxe
Ground
thawing
depth (cm)
Surface air
temperature,
ºC
Soil temperature ºC
Depth (cm)
5 10 20 30 40 50 80
Intact 11.8±8.5 60-80 24.3 13.7 10.2 6.9 4.9 3.9 3 0.6
Silk moth
affected
26.8±4.2 110 24.6 16.3 13.1 9.2 7.5 6.4 5.0 0.7
1 From Averensky et al., 2010.
The increase in temperature on the forest floor can also represent a threat to
permafrost taiga landscapes as it leads to the development of thermokarst
(irregular surfaces that form lakes) as higher soil temperatures thaw the
permafrost, thereby increasing the soil water content (Averensky et al., 2010).
Methane, a powerful greenhouse gas, stored in the permafrost is released into
the atmosphere leading to an increase in greenhouse gases and potentially
contributing to global climate change (Anisimov, 2007; Zhuang et al., 2009 ).
The massive amounts of frass produced during an outbreak directly affect soil
fertility and increase the levels of microorganisms such as ammonifying
phototrophs and microorganisms involved in humus mineralization. Frass also
increases the leaching of water soluble carbon (Krasnoshchekov and
Bezkorovainaya, 2008; Krasnoshchekov and Vishnyakova, 2003 ).
There are no known US distributions of hosts for Dendrolimus moths listed on
the Federally Registered Threatened and Endangered Species lists.
2-42 Dendrolimus Pine Moths 12/2012-01