Honey Bees,  Mites, and Neonicotinoid Insecticides…What’s causing our honey bee decline


By Bob Dailey

Honey bees are disappearing at alarming rates across the globe and scientists are still scrambling to find out the causes.

Since honeybees are responsible for pollinating 30% of the world’s food crops and 90% of our wild plants, the decline is something to sit up and take notice of.

Significant declines in the world’s honey bee populations began around 2006. Of course, this is not the first time that the world has seen bee decline. It’s occurred more than once in the 4,000 plus years since the ancient Egyptians began keeping bees.

But this time, the decline seems to be different. Beekeepers report that during the 2012-2013 winter, they lost 45.7 percent of their hives. So what’s causing it?

U.S. scientists and bee experts all agree that the two types of mites, the Varoa mite (Varoa destructor) and the Tracheal mite (Acarapis woodi) are the two most significant thugs in the bee world. Varoa infest both the brood and adult stages of bees. Feeding on the blood of the bee, they weaken the insect and also infect it with viruses. Studies have also shown that secondary infections from Varoa causes bees to become disoriented and not able to find their way back to the hive.

The Tracheal mite lays eggs inside the tracheae (the breathing apparatus) of bees. It also feeds on the blood of bees, but also weakens them by inhibiting their breathing ability.

But mites are not the only culprits. A relatively new type of insecticide, called neonicotinoid, is also affecting bee colonies. The name “neonicotinoid” literally means “new nicotine-like insecticides. Although the jury is still out on how much neonicotinoids affect the Colony Collapse Syndrome, there is pertinent data about the insecticide that lends credibility to the situation.

In the report “Are Neonicotinoids Killing Bees, A Review of Research into the Effects of Neonicotinoid Insecticides on Bees, with Recommendations for Action.” by Jennifer Hopwood, Mace Vaughan, Matthew Shepherd, David Biddinger, Eric Mader, Scott Hoffman Black, and Celeste Mazzacano.

Some of the findings of the report:

  • Neonicotinoid residues are found in pollen and nectar consumed by pollinators such as bees and butterflies. The residues can reach lethal concentrations in some situations.
  • Neonicotinoids can persist in soil for months or years after a single application. Measurable amounts of residues were found in woody plants up to six years after application.
  • Untreated plants may absorb chemical residues left over in the soil from the previous year.
  • Products approved for homeowners to use in gardens, lawns, and on ornamental trees have manufacturer-recommended application rates up to 120 times higher than rates approved for agricultural crops. 

Insecticides that contain neonicotinoids include

A number of scientist agree that the effects of neonicotinoids should be investigated. In fact, the European Union has placed  moratorium on the sale of the product until further research can be conducted on its effects on bees.

Dr. Michael Merchant, Texas A&M Agrilife Extension Urban Entomologist, notes in a recently published abstract that two reports in Science magazine showed that neonicotinoids disrupted the homing abilities of foraging honey bees and colony growth in bumble bees. A Harvard School of Public Health study links the use of neonicotinoids to the ongoing demise of honey bee colonies. Dr. Merchant does add that this research has been “challenged by pesticide manufacturers and some researchers.”

There are currently 465 neonicotinoid-containing products on the U.S. market now, most of them readily available to consumers for backyard use.

The EPA, although not officially banning the use of neonicotinoids, has taken two important steps in regulating them. First, the EPA has said it will likely not approve “most applications of new use of these chemicals” until it obtains new data and research on possible dangers to pollinators.

The EPA also requires that all insecticides which may harm bees be labeled with the “Bee Box”that alerts users to not use if bees are present in the area, which is most of the time.

About 95 percent of the corn seeds in the world are treated with neonicotinoids, which supposedly increases yield by reducing insect predation. Neonicotinoid-treated soybean seeds are also widespread, although the EPA has recently released a study that says treating the seeds offers little,if any, economic benefit to soybean farmers’ economic bottom lines. In other words, some farmers are using pesticide-treated seeds they don’t need.

In addition to honey bees concerns, the USDA has released a report that links neonicotinoids to monarch butterfly decline. Researchers found that milkweed containing neonicotinoids “could negatively affect larval monarch populations.”

The jury is still out on the effects of neonicotinoids on bees. Many researchers believe there the chemicals have no provable effects on bees. Others say there is an abundance of evidence.

Whatever one’s feelings lie, there are alternatives to neonicotinoids.

Aphids and many other pest species are attracted to plants fertilized with high nitrogen products, a typical component of synthetic fertilizer operations. Organic compost, compost teas, low-nitrogen  organic fertilizers and fish emulsions release nitrogen slowly into the soil and aphids tend to avoid them.

Diversity in a garden is best. Plant a wide variety of native flowers, grasses and bushes to encourage natural predators like birds and ladybugs.

For lawns, use organic compost at least twice a year. Raise the mower blade and leave at least 2+ inches of grass blade. Sharpen mower blades.

Both Home Depot and Lowes have announced that they will ban insecticides that contain neonicotinoids, and are requiring that plants which have been sprayed with the inseciticide be labelled as such before being sold.

A partial list of products containing neonicotinoids include:

  • Bayer Advanced 3-in-1 Insect, Disease, & Mite Control
  • Bayer Advanced 12 Month Tree & Shrub Insect Control
  • Bayer Advanced 12 Month Tree & Shrub Protect & Feed
  • Bayer Advanced Fruit, Citrus & Vegetable Insect Control
  • Bayer Advanced All-in-One Rose & Flower Care concentrate
  • DIY Tree Care Products Multi-Insect Killer
  • Ferti-lome 2-N-1 Systemic
  • Hi-Yield Systemic Insect Spray
  • Hunter
  • Knockout Ready-To-Use Grub Killer
  • Lesco Bandit
  • Marathon
  • Merit
  • Monterey Once a Year Insect Control II
  • Ortho Bug B Gon Year-Long Tree & Shrub Insect Control
  • Ortho MAX Tree & Shrub Insect Control
  • Surrender Brand GrubZ Out
  • Bayer Advanced All-in-One Rose & Flower Care granules
  • Flagship
  • Greenlight Grub control with Arena
  • Maxide Dual Action Insect Killer
  • Meridian
  • Ortho flower, Fruit and Vegetable Insect Killer
  • Ortho Rose and Flower Insect Killer
  • Green Light Tree and Shrub Insect Control with Safari 2G
  • Safari
  • Transect
  •  Zylam 20SG Systemic Turf Insecticide
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Bob Dailey

Bob Dailey is a garden writer, lecturer and gardener living in southeast Texas.

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