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The eradication strategy used in B.C. relies on a systematic monitoring program using
pheromone traps to locate and estimate the size of recently introduced populations of the
gypsy moth. The number of traps and their placement is determined each year by the Gypsy
Moth Technical Committee of the BCPPAC. This monitoring program is conducted by the
Canadian Food Inspection Agency (CFIA), who place traps throughout the province in
cooperation with the B.C. Ministry of Forests, B.C. Ministry of Agriculture and Food, BC
Parks, and the Canadian Forest Service. A monitoring program places traps at a very
low density, typically no more than 1 trap per square mile.
If male moths are trapped, the trap density in the following year is increased to a
density of 32 to 64 traps per square mile. Increasing the density of traps allows the area
that a gypsy moth population has begun to take a foothold. This is commonly known as delimiting
trapping.
Following treatment, the density of traps remains high at 32 to 64 traps per square
mile for the first year within the treated area, and 16 traps square mile within a half
mile radius. In the second year, the density is reduced to 16 traps per square mile and
then returns to 1 trap per square mile in the third year. A population is considered to be
eradicated after two years have passed without any moths trapped. After the area has been
declared free of gypsy moth, the trapping density returns to monitoring levels.
An example of this trap distribution is shown in the
Trapping
Placement Map from 1997. This method of varying trapping density is a standardized method used
by provinces and states that follow an eradication strategy to deal with introductions of
gypsy moth.
Current trap catch data is supplied in a table
along with the complete history of gypsy moth trapping in B.C.
Traps are placed in early summer well before the expected flight period in late July
through August. Each trap contains the synthetic female pheromone called Disparlure ®
which is contained within a lure that is stapled inside the trap. The pheromone is
extremely effective at attracting male moths. The inside of the trap is coated with a
sticky material that traps and holds the moth. Traps are collected in the late fall and
the data is summarized by the CFIA. When adult male moths are caught, their location and
the location of all traps are plotted on maps and these data points are later used to
establish further detection and treatment efforts
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