Hobbies And Interests
Insecticides Can Kill Bees
Pesticides are ranked by how toxic they are to bees with those rankings ranging from a few that are relatively non-toxic to many that are classified as being highly toxic to bees. Some pesticides are so toxic to bees that they have been banned from use in some countries, while others should never be used if crops are flowering, or require pollination or if bees are active. Honey bees are an important pollinator of food crops.
Protecting Bees Is Complicated
Protecting bees from pesticide poisoning is complicated by the fact that farmers often use chemical insecticides to protect crops from insects that are pests. Unfortunately, pesticides used to target destructive insects can also kill the beneficial ones.
In fact, two commonly used pesticides are suspected of playing a part in the mysterious colony collapse that is causing entire populations of honey bee hives to die. United States Environmental Protection Agency officials have identified two specific neonicotinoids chemical pesticides, imidacloprid and clothianidin, as being particularly toxic to honey bees.
Ways Insecticides Kill Bees
"Insecticides affect bees in one or more ways: as stomach poisons, as contact poisons, and as fumigants," according to Dr. James E. Tew, a professor at Ohio State University. Tew wrote those comments in a fact sheet titled "Protecting Honey Bees from Pesticides."
Bees can be exposed to pesticides if they are sprayed directly on bees, or the pesticides drift through the air to where bees are present, or if the bees come in contact with a surface that has insecticide on it.
Stomach Poisons
Toxic insecticides can get into a bee's stomach in a variety of ways. Pesticides that have been sprayed on plants, especially the blossoms of flowering plants, can get into the pollen or nectar that bees carry back to the hive to make honey. That, in turn, can affect the entire hive. That is why many pesticides are not supposed to be used in areas where bees are active, particularly if a crop requires pollination.
Also, pesticide that has been sprayed near water sources or that has drifted over water can affect bees if they later collect and consume that water.
Contact Poisons
Contact poisons work by touching an insect or getting on it. Although pesticides are targeted to specific insects, if bees come in contact with those chemicals, even if they are not considered poisonous, they can still be toxic enough to kill bees. Contact poisons often act fairly quickly and can result in death or paralysis in a short time. Pesticides often kill by being absorbed into the bee and affecting the insect's central nervous system.
Fumigants
"Fumigants are insecticides in the form of gases that are slightly heavier than air and have the ability to spread to all areas of a sealed structure," University of Minnesota Extension agents wrote in a paper on fumigants.
Farmers often use fumigants in grain storage bins or structures. Fumigants are highly toxic, restricted-use chemicals and are similar to the infamous "mustard" gases used in World War I. Not only can fumigants kill by suffocation in the structure where they have been applied, but also because they are able to seep through cracks and crevices, there is a risk that the chemicals can kill people, animals or insects, including honey bees, that are nearby.