This spring, the Kenosha County Department of Public Works & Development Services will
be overseeing aerial spray treatments to control the significant presence of the invasive
spongy moth in an identified outbreak area.
Spraying will occur along the east side of Highway KD north of Highway C in the Town of
Randall and the Village of Twin Lakes. (A map of the area appears on the final page of this
news release.)
This spraying will occur in two applications made three to 14 days apart, between the dates
of May 13 and July 1. The timing of the spraying is dependent upon the development of the
spongy moth larvae and local weather conditions, said Vijai Pandian, Horticulture Educator
with Extension Kenosha County.
A low-flying helicopter will spray a biological pesticide called Bacillus thuringiensis var.
kurstaki (Btk). Btk is a bacterium that occurs naturally in the soil. Like other bacteria,
Btk forms spores, but unique to this species, it also forms protein crystals that are toxic to
the susceptible caterpillars when ingested.
“Btk is not toxic to people or animals,” Pandian said. “Based on epidemiological studies and
the long history of its use, there is no evidence that the application of Btk formulations
causes any effects to people or animals in treated areas. It affects caterpillars, and only
caterpillars, when they eat leaves that have Btk on their surfaces.”
Formerly known as the gypsy moth, the spongy moth (Lymantria dispar) is an established
invasive insect that defoliates more than 300 species of trees including oaks, birch, lindens,
crabapple, aspen and willows. During its last major outbreak, in 2010, nearly 347,000 acres
of tree defoliation occurred in Wisconsin.
COUNTY OF KENOSHA
Prevention measures and other resources:
To help slow further spread of the spongy moth in Kenosha County’s current outbreak area,
Pandian encourages property owners in Twin Lakes and Randall to use sticky barrier band
traps to reduce the young caterpillar population in their trees.
More details are available in an informational piece from the UW-Madison Division of
Extension, available at https://fyi.extension.wisc.edu/spongymothinwisconsin/pest-
management-2/making-a-sticky-barrier-band/.
A resource page with more information about the spongy moth and links to various related
resources is avalable on the Kenosha County website, at
https://www.kenoshacounty.org/spongymoth.
Anyone with questions about this effort may contact the Kenosha County Department of
Public Works & Development Services at 262-857-1870.
