What is a neonicotinoid?

oleander aphids

Neonicotinoids are especially effective against sap-feeding insects like aphids.

Neonicotinoids are a new class of insecticides chemically related to nicotine. The name literally means “new nicotine-like insecticides”.  Like nicotine, the neonicotinoids act on certain kinds of receptors in the nerve synapse.  They are much more toxic to invertebrates, like insects, than they are to mammals, birds and other higher organisms.

One thing that has made neonicotinoid insecticides popular in pest control is their water solubility, which allows them to be applied to soil and be taken up by plants.  Soil insecticide applications reduce the risks for insecticide drift from the target site, and for at least some beneficial insects on plants.

There are several different kinds of neonicotinoid insecticides.  The first neonicotinoid to reach the market was imidacloprid, a common ingredient in Bayer Advanced Garden insecticides.  This product can be sprayed on the plant, but is often more effective (especially on sucking insects) when applied to the soil.  Dinotefuran (Safari) is another, more highly water-soluble, neonicotinoid that is especially good on sap-feeding insects.

To find out whether an insecticide you see on the shelf of your hardware, pest control supply or garden center is a neonicotinoid, look on the list of active ingredients. If you see one of the following names listed, the insecticide includes a neonicotinoid:

  • Acetamiprid
  • Clothianidin
  • Dinotefuran
  • Imidacloprid
  • Nitenpyram
  • Thiocloprid
  • Thiamethoxam

In addition to being effective against sap-feeding pests, neonicotinoids provide good control against certain beetles (like white grub larvae in lawns), fleas (Advantage flea control products, and nitenpyram pills for pets), certain wood boring pests, flies (fly baits), cockroaches and others.

Environmental concerns

Initially neonicotinoids were praised for their low-toxicity to many beneficial insects, including bees; however recently this claim has come into question. New research points to potential toxicity to bees and other beneficial insects through low level contamination of nectar and pollen with neonicotinoid insecticides used in agriculture. Although these low level exposures do not normally kill bees directly, they may impact some bees’ ability to foraging for nectar, learn and remember where flowers are located, and possibly impair their ability to find their way home to the nest or hive. Despite the controlled studies completed to date, the actual impact of neonicotinoid insecticides on honey bees in the field are difficult to measure.  It is still not known whether these effects explain bee colony collapse disorder, or have had any effect in agriculture or, especially, in urban areas.

The relative infrequency with which bees are expected to encounter neonicotinoid insecticides in urban landscapes suggest that the impact of these insecticides in backyard gardens, when used appropriately, is probably minor.  To keep risk to bees and other beneficials low, however, a few simple steps should be taken: (1) follow the label directions carefully, (2) restrict neonicotine applications to the soil, or during times when bees are not foraging (e.g., in the evening), and (3) treat only those individual plants which need treatment for a known pest infestation.

4 Responses to What is a neonicotinoid?

  1. Kathy Cummings says:

    Following the Precautionary Principle, it’s wiser for us to stop giving neonicotinoids to bees now than waiting for them to disappear. Better safe than sorry!

    The above link was two years ago. What are we waiting for?

    • m-merchant says:

      The Precautionary Principle is based on the belief that any use of an insecticide should be avoided without airtight evidence that it is 100% safe. The problem with that principle is that 100% certainty safety is impossible to prove–ever. It also ignores the fact that there are benefits to using some insecticides, and that most environmental rules and decisions have always been based on balancing benefits vs. risks. If there were no benefits to humans of using these insecticides, we wouldn’t be having this conversation. But there are, so we proceed on the best available science to make decisions about what the risks and benefits are. BTW, in the U.S. over the past two years, the science on the safety of neonicotinoids has been equivocal. New studies have shown that bees may be more sensitive to neonics than we previously thought; but an increasing number of studies are showing that the bee problem known as CCD is most likely being caused by several factors other than insecticides. No studies have yet confirmed that use of neonictinoids per label directions are causing harm to pollinator populations. If you interested in reading more about this important and controversial topic, click here.

  2. Marianna Smith says:

    “restrict neonicotine applications to the soil, or during times when bees are not foraging (e.g., in the evening)” how is this going to help prevent the bees from ingesting the neonicotine? It disappears in less then half a day?

    • m-merchant says:

      Good question! Neonicotinoids do not disappear from inside a treated plant that quickly–you are correct. However, generally once insecticides dry, and are exposed to the degrading effects of sunlight, they tend not to be highly toxic to foraging pollinators. Many factors are involved in this including the absorption of insecticides into plant tissue, adherence of the insecticides to the plant, and the likelihood of the pollinator staying on a treated plant long enough to pick up a biologically significant dose. As far as neonics inside the plant harming a pollinator, most neonics are xylem transmitted, and tend to end up in leaves and stem tissue, with very low amounts in pollen and even less in nectar. These low amounts are presumed to not be harmful to bees, and are much less likely to cause harm than wet (or dry) leaf deposits.

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