New Pest Response Guidelines - aphis - US Department of Agriculture

Pest Information
Dendrolimus superans
Because of taxonomic similarities, most information about behavior of
Dendrolimus superans is combined with D. sibiricus and is not distinguished
in the literature. Therefore, consult sections on D. sibiricus behavior for what
is known about these moths.
Population Dynamics
Localized outbreaks of Dendrolimus moths generally follow periodic cycles in
timing. Certain conditions have been observed to play an increased role in the
outbreaks. Environmental factors of temperature and precipitation are most
closely correlated with these outbreaks, but the proximate causes are still not
well understood. Details for each species are included below.
Dendrolimus pini
Pine-tree lappet outbreaks are periodical and have been reported in Germany,
Poland, Lithuania, Austria, Hungary, Ukraine, Czech Republic, Russia and
China (Gedminas, 2003; Han et al., 2004; Kolubajiv, 1950; Komarek and
Kolubajiv, 1941; Lesniak, 1976; Malyshev, 1997; Meshkova, 2002;
Mozolevskaya et al., 2002b; Sierpinska, 1998; Varga, 1966; Varley, 1949). In
Lithuania, outbreaks were first reported in 1993 and in Hungary in 1969
(Gedminas and Ziogas, 2008; Varga, 1966). Data available for outbreaks in
Poland since 1791 shows periodic outbreaks lasting from 1 to 11 years
(Sierpinska, 1998). In the present century, these outbreaks have been reported
more frequently in Poland and Germany. In Poland, the average time between
outbreaks was 40 years during the 19 and 20 th centuries, compared to 7 year
intervals in the present century (Sierpinska, 1998). Climatic and
meteorological conditions are important factors determining the extent of a
population outbreak (Lesniak, 1976). Temperature, relative humidity,
precipitation, and number of days with snow covering the ground are among
the most important factors. Regions with the most severe outbreaks are
characterized by high mean annual temperature (average of 7.8°C) (Lesniak,
1976). Outbreaks will normally occur when the isotherm line in July is around
a minimum value of 18°C and for January, the coldest month, around -2.0°C.
Outbreaks are usually weaker when the number of days with temperatures
below freezing exceeds 50 (Lesniak, 1976).
Outbreaks are also determined by the amount of precipitation in an area. Low
precipitation (less than 350mm during the summer) in the driest, warmest areas
is a favorable condition (Lesniak, 1976). The amount of snow cover is a factor
that will affect the hibernating larvae. The duration and amount of snow cover
can have a direct and indirect impact on the survival of hibernating larvae. The
lack of snow cover and therefore, insulation, can result in an increased
12/2012-01 Dendrolimus Pine Moths 2-33