60 Nebraskaland • June 2022
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Japanese beetles (Popillia japonica) are exotic, invasive
insects first introduced to the United States around 1916, on
nursery stock. Since its introduction, the Japanese beetle has
become established in almost every state in the eastern half
of the country. It is a highly destructive insect, with both the
adult and grubs causing damage to plant roots, foliage and
flowers.
Japanese beetles have been found in many Nebraska
counties. Typically, a county is considered infested when
adult beetles have been caught in traps in the county for two
consecutive years, or when more than one life stage (an egg,
grub or adult) is confirmed in the same year. The Nebraska
Department of Agriculture has conducted trapping surveys
for the beetles for decades. For regulatory purposes, based on
survey results and the large number of counties confirmed as
infested, the state shifted to fully infested status under the
terms of the U.S. National Japanese Beetle Harmonization
Plan in 2021.
As Japanese beetles become more common across the state,
the prevalence of this pest has implications for nurseries that
ship out of state, along with homeowners making
management
decisions.
Many states
require nursery stock shipped interstate to meet the
certification requirements found in the harmonization plan
or have Japanese beetle quarantines that prohibit or limit the
movement of nursery stock from infested areas. Nebraska
nursery stock may need special certification, in addition to a
regular nursery inspection and license, to meet other states'
entry requirements. This process may require soil sampling,
trapping surveys, inspections and/or chemical treatments.
The Nebraska Department of Agriculture's Entomology staff
regularly work with nurseries to meet these certification
requirements.
Japanese beetles are known to move in infested nursery
stock. To prevent the spread of invasive species, purchase
only certified plants from licensed nurseries. Inspect plants
for evidence of pests before purchasing and putting in your
landscape.
There are a number of chemical options available for
managing Japanese beetles. Check with the Nebraska
Extension for additional Japanese beetle management
recommendations.
JAPANESE BEETLES
By Julie Van Meter, State Entomologist
Nebraska Department of Agriculture
Adult Japanese beetle.
DAVID CAPPAERT, BUGWOOD.ORG
