Pesticide Toxicity To Bees
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Pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
vary in their effects on
bees Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...
. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other areas around it. Systemic pesticides, on the other hand, are usually incorporated into the soil or onto seeds and move up into the stem, leaves, nectar, and pollen of plants. Of contact pesticides, dust and wettable powder
pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
tend to be more hazardous to bees than solutions or emulsifiable concentrates. When a bee comes in contact with pesticides while foraging, the bee may die immediately without returning to the hive. In this case, the
queen bee A queen bee is typically an adult, mated female (gyne) that lives in a colony or hive of honey bees. With fully developed reproductive organs, the queen is usually the mother of most, if not all, of the bees in the beehive. Queens are developed ...
, brood, and nurse bees are not contaminated and the colony survives. Alternatively, the bee may come into contact with an insecticide and transport it back to the colony in contaminated pollen or nectar or on its body, potentially causing widespread colony death. Actual damage to bee populations is a function of toxicity and exposure of the compound, in combination with the mode of application. A systemic pesticide, which is incorporated into the soil or coated on seeds, may kill soil-dwelling insects, such as grubs or
mole cricket Mole crickets are members of the insect family Gryllotalpidae, in the order Orthoptera (grasshoppers, locusts, and crickets). Mole crickets are cylindrical-bodied, fossorial insects about long as adults, with small eyes and shovel-like fore ...
s as well as other insects, including bees, that are exposed to the leaves, fruits, pollen, and nectar of the treated plants. Pesticides, especially
neonicotinoids Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active insecticides chemically similar to nicotine, developed by scientists at Shell and Bayer in the 1980s. The neonicotinoid family includes acetamiprid, clothianidin, din ...
, have been investigated in relation to
Colony Collapse Disorder Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While s ...
. Potentially toxic effects studied in the laboratory have often been followed by field studies that fail to show effects on actual bee populations. Despite gaps in the scientific evidence, regulators have restricted the use of neonicotinoids in Europe and elsewhere largely on the basis of concerns for bee health.


Classification

Insecticide toxicity is generally measured using acute contact toxicity values – the exposure level that causes 50% of the population exposed to die. Toxicity thresholds are generally set at * highly toxic (acute LD50 < 2 μg/bee) * moderately toxic (acute LD50 2 - 10.99μg/bee) * slightly toxic (acute LD50 11 - 100μg/bee) * nontoxic (acute LD50 > 100μg/bee) to adult bees.


Pesticide toxicity


Acute toxicity

The acute toxicity of pesticides on bees, which could be by contact or ingestion, is usually quantified by . Acute toxicity of pesticides causes a range of effects on bees, which can include agitation, vomiting, wing paralysis, arching of the abdomen similar to sting reflex, and uncoordinated movement. Acute toxicity may depend on the mode of exposure, for instance, many pesticides cause toxic effects by contact while neonicotinoids are more toxic when consumed orally. The acute toxicity, although more lethal, is less common than sub-lethal toxicity or cumulative effects.


Sublethal and chronic effects

Field exposure to pesticides, especially with relation to neonicotinoids, may lead to multiple physiological and/or behavioral sublethal effects in exposed bees. Sublethal effects to honey bees can include disruptions to behavioral and motor functions, compromised immunity, and delayed development.


Colony collapse disorder

Colony collapse disorder Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While s ...
(CCD) is a syndrome that is characterized by the sudden loss of adult bees from the hive. Many possible explanations for it have been proposed, but no one primary cause has been found. The US Department of Agriculture indicated in a 2010 report to Congress that a combination of factors could be causing colony collapse disorder, including pesticides, pathogens, and parasites. Although pesticides were suspected to be part of the problem, a survey of healthy and CCD-affected colonies revealed similar levels of pesticides in wax and pollen.


Bee kill rate per hive

The kill rate of bees in a single bee hive can be classified as: :< 100 bees per day - normal die off rate :200-400 bees per day - low kill :500-900 bees per day - moderate kill : 1000+ bees per day - High Kill


Pesticide formulations

Pesticides come in different formulations: *Dusts (D) *Wettable powders (WP) *Soluble powders (SP) *Emulsifiable concentrates (EC) *Solutions (LS) *Granulars (G)


Pesticides

All substances listed are insecticides, except for 2,4-D, which is an herbicide. Some substances are arachnicides too.


Highly toxic and banned in the US

*
Aldrin Aldrin is an organochlorine insecticide that was widely used until the 1990s, when it was banned in most countries. Aldrin is a member of the so-called "classic organochlorines" (COC) group of pesticides. COCs enjoyed a very sharp rise in popular ...
Banned by US EPA in 1974. *
Dieldrin Dieldrin is an organochloride originally produced in 1948 by J. Hyman & Co, Denver, as an insecticide. Dieldrin is closely related to aldrin, which reacts further to form dieldrin. Aldrin is not toxic to insects; it is oxidized in the insect to fo ...
Banned by US EPA in 1974. *
Heptachlor Heptachlor is an organochlorine compound that was used as an insecticide. Usually sold as a white or tan powder, heptachlor is one of the cyclodiene insecticides. In 1962, Rachel Carson's ''Silent Spring'' questioned the safety of heptachlor and ...
*
Lindane Lindane, also known as ''gamma''-hexachlorocyclohexane (γ-HCH), gammaxene, Gammallin and benzene hexachloride (BHC), is an organochlorine chemical and an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and ...
, BHC Banned in California. Banned for agricultural use in the US by the EPA in 2006.


Regulatory policy

Based on a risks to bee health as identified by the
European Food Safety Authority The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
(EFSA), in April 2013 the EU decided to restrict the use of the
neonicotinoids Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active insecticides chemically similar to nicotine, developed by scientists at Shell and Bayer in the 1980s. The neonicotinoid family includes acetamiprid, clothianidin, din ...
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
,
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
, and
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system ...
. Fipronil was also banned for use on maize and sunflowers. In 2015, the US
Environmental Protection Agency A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
(EPA) proposed to prohibit the application of certain pesticides and herbicides that are known to be toxic to bees during
pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...
periods when crops are in bloom. Seed treatments were not considered to present a risk to bee health. A modified form of these proposals was adopted as EPA policy in January 2017. In April 2018, member states of the European Union agreed upon a total ban on neonicotinoid insecticide use, except within closed greenhouses. The vote on the proposed ban followed a February 2018 report from the EFSA which concluded that neonicotinoids posed a high risk to both domestic and wild bees. The ban had strong public support, but faced criticism from the agrochemical industry, and from certain farmers' groups. In 2020, the EPA supplemented its policy with a proposal to restrict the use of neonicotinoids on residential lawns and turf, but otherwise confirmed that they would remain in use in the US.


General measures to prevent pesticide bee kills


Application of pesticides at evening or night

Avoiding the application of pesticides directly to blooming flowers can help limit the exposure of honeybees to toxic materials. If blooming flowers must be sprayed with pesticides for any reason, they should be sprayed in the evening or night hours when bees are not in the field. The usual foraging hours of honeybees are during the daytime when the temperature is above .


See also

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Bees and toxic chemicals Bees can suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals, particularly insecticides, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from ...
*
Colony Collapse Disorder Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While s ...
*
Neonicotinoids Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active insecticides chemically similar to nicotine, developed by scientists at Shell and Bayer in the 1980s. The neonicotinoid family includes acetamiprid, clothianidin, din ...
*
United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...
*
Pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...
*
Endangered arthropod As of July 2016, the International Union for Conservation of Nature (IUCN) lists 616 endangered arthropod species. 6.5% of all evaluated arthropod species are listed as endangered. The IUCN also lists 27 arthropod subspecies as endangered. No ...
*
Pesticide misuse Under United States law, pesticide misuse is considered to be the use of a pesticide in a way that violates laws regulating their use or endangers humans or the environment; many of these regulations are laid out in the Federal Insecticide, Fungic ...
*
Pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s *
Pollinator decline Pollinator decline is the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide that began being recorded at the end of the 20th century. Multiple lines of evidence exist for the reduction of wild pollinator ...
*
Fipronil Fipronil is a broad-spectrum insecticide that belongs to the phenylpyrazole chemical family. Fipronil disrupts the insect central nervous system by blocking the ligand-gated ion channel of the GABAA receptor and glutamate-gated chloride (GluCl ...
* Imidacloprid effects on bees * Honey bee starvation


References


External links

* * * * * * *
US EPA Pesticide Registration (PR) Notice 2001-5

Bee Health: Background and Issues for Congress
Congressional Research Service The Congressional Research Service (CRS) is a public policy research institute of the United States Congress. Operating within the Library of Congress, it works primarily and directly for members of Congress and their committees and staff on a c ...

Bee Health: The Role of Pesticides
Congressional Research Service The Congressional Research Service (CRS) is a public policy research institute of the United States Congress. Operating within the Library of Congress, it works primarily and directly for members of Congress and their committees and staff on a c ...
* {{DEFAULTSORT:Pesticide Toxicity To Bees Bee ecology Beekeeping Bees, Toxicity