16
Pesticides, Organic Contaminants, and Pathogens in Air
and are especially effective on sucking insects such as aphids. Neonics
are registered for use on a wide variety of crops worldwide including citrus, pome fruit, stone fruit, cotton, and cereal grains. They were
developed as an alternative to OPs and carbamates. Imidacloprid was
frst registered in California in 1994, while the other three active ingredients were registered in 2004.
A reevaluation can be triggered in a variety of different ways, such
as issues with phytotoxicity or effcacy, or concerns over impacts on
worker health or the environment. As mentioned previously, the
neonic reevaluation was triggered by adverse effects data submitted
by the registrant, which showed high levels of imidacloprid in both
leaves and blossoms of treated plants. These levels were high enough
to be expected to be hazardous to bees. Based on DPR’s evaluation of
the adverse effects data, DPR issued California Notice 2009-02, which
formally placed the four neonic active ingredients into reevaluation in
February 2009. The reevaluation focuses on outdoor agricultural uses
of neonics and does not include products that are not relevant to the
concerns that prompted the reevaluation. This means that products
such as ant and cockroach baits or indoor use products were not pulled
into the reevaluation. For more information on the specifcs of the initiation of this reevaluation, contact CDPR or visit DPR’s Neonicotinoid
Reevaluation Web page
After DPR initiated the reevaluation, staff began working collaboratively with U.S. EPA and the Health Canada Pest Management
Regulatory Agency to determine data requirements and develop study
designs. DPR’s neonic reevaluation relies on data submitted by the registrants and peer-reviewed open literature studies. The specifc data
required included honeybee toxicity studies, colony feeding studies,
and pollen nectar residue studies. DPR worked with U.S. EPA on the
preliminary pollinator risk assessments, looking at acute toxicity endpoints as well as preliminary residue studies and colony feeding studies. U.S. EPA issued the preliminary risk assessment for imidacloprid
in January 2016 and for clothianidin, thiamethoxam, and dinotefuran
in January 2017.
In July 2018, DPR published the California Neonicotinoid Risk
Determination. For this risk determination, DPR scientists assessed
data from residue trials of the four neonicotinoids at various rates and
timings, and compared them to colony feeding studies. The data from
the colony feeding studies was used to determine residue levels that
pose no signifcant toxicity to bees. The residue studies assessed in the
document were conducted under worst-case scenarios, based on the
maximum application rates and minimum reapplication intervals listed
Pesticides, Organic Contaminants, and Pathogens in Air
and are especially effective on sucking insects such as aphids. Neonics
are registered for use on a wide variety of crops worldwide including citrus, pome fruit, stone fruit, cotton, and cereal grains. They were
developed as an alternative to OPs and carbamates. Imidacloprid was
frst registered in California in 1994, while the other three active ingredients were registered in 2004.
A reevaluation can be triggered in a variety of different ways, such
as issues with phytotoxicity or effcacy, or concerns over impacts on
worker health or the environment. As mentioned previously, the
neonic reevaluation was triggered by adverse effects data submitted
by the registrant, which showed high levels of imidacloprid in both
leaves and blossoms of treated plants. These levels were high enough
to be expected to be hazardous to bees. Based on DPR’s evaluation of
the adverse effects data, DPR issued California Notice 2009-02, which
formally placed the four neonic active ingredients into reevaluation in
February 2009. The reevaluation focuses on outdoor agricultural uses
of neonics and does not include products that are not relevant to the
concerns that prompted the reevaluation. This means that products
such as ant and cockroach baits or indoor use products were not pulled
into the reevaluation. For more information on the specifcs of the initiation of this reevaluation, contact CDPR or visit DPR’s Neonicotinoid
Reevaluation Web page
After DPR initiated the reevaluation, staff began working collaboratively with U.S. EPA and the Health Canada Pest Management
Regulatory Agency to determine data requirements and develop study
designs. DPR’s neonic reevaluation relies on data submitted by the registrants and peer-reviewed open literature studies. The specifc data
required included honeybee toxicity studies, colony feeding studies,
and pollen nectar residue studies. DPR worked with U.S. EPA on the
preliminary pollinator risk assessments, looking at acute toxicity endpoints as well as preliminary residue studies and colony feeding studies. U.S. EPA issued the preliminary risk assessment for imidacloprid
in January 2016 and for clothianidin, thiamethoxam, and dinotefuran
in January 2017.
In July 2018, DPR published the California Neonicotinoid Risk
Determination. For this risk determination, DPR scientists assessed
data from residue trials of the four neonicotinoids at various rates and
timings, and compared them to colony feeding studies. The data from
the colony feeding studies was used to determine residue levels that
pose no signifcant toxicity to bees. The residue studies assessed in the
document were conducted under worst-case scenarios, based on the
maximum application rates and minimum reapplication intervals listed