Italy: Study finds 72.2% of dead honey bees samples tested, contained a pesticide

Study: Spring mortality in honey bees in northeastern Italy: detection of pesticides and viruses in dead honey bees and other matrices

Marianna Martinello, Chiara Baratto, Chiara Manzinello, Elena Piva, Alice Borin, Marica Toson, Anna Granato, Maria Beatrice Boniotti, Albino Gallina & Franco Mutinelli (2017); published in Journal of Apicultural Research; Volume 56, 2017 - Issue 3; April 2017.

Main points from the abstract:

  • In spring there is often a rise in honey bee mortality incidents (i.e honey bee deaths).

  • Study aim:

    to investigate the potential correlation, in the reported incidents, between exposure to pesticide treatments and virus infections.

  • Region: northeastern Italy during spring 2014

  • 150 active ingredients and three honey bee viruses in dead honey bees and other matrices were monitored.

When the dead honey bees were analysed, what were the findings?

  • At least one active pesticide ingredient was found in 72.2% of the 79 dead honey bee samples, with the most abundant (59.4%) being insecticides.
  • The insecticides mainly belonged to the class of neonicotinoids (41.8%), followed by fungicides (40.6%). Imidacloprid (neonicotinoid), chlorpyrifos, tau-fluvalinate, and cyprodinil were the most frequently detected active ingredients.
  • DiseasesMultiple virus infections were monitored, revealing a high prevalence of chronic bee paralysis virus (CBPV) and deformed wing virus (DWV), detected in all samples except one. 71 and 37% of the CBPV- and DWV positive samples, respectively, showed a high number of viral copies per bee (>107).
  • This work emphasizes the possible relationship between spring mortality in honey bees and pesticide treatments.
  • Honey bee viruses could synergistically exacerbate the negative impact of pesticides on honey bee health, endangering the survival of colonies.

To see the study, copy and paste this link into your browser:


A link between neonicotinoids and diseases, which would  ultimately cause colony death, would hardly be surprising. 

Bayer CropScience refer to this function of their neonicotinoid (imidacloprid) Termite treatment - i.e. to cause demise of the termite colony through disease.  They state that after 3 months, a termite colony will be eliminated.  Termite colonies, like bees, are social insects, and the colony itself can be referred to as a super-organism.

Here is the quote from the Premise 200SC leaflet:

The leaflet reads:

    “The termites are susceptible to diseases or fungi found in soil. A principle part of their defence mechanism is their grooming habits, which allows the termites to get rid of the fungal spores before these spores germinate and cause disease or death. Premise 200SC interferes with this natural process by lowering defence to nature’s own weaponry.”

    "What is Premise 200SC plus Nature?

    Low doses of imidacloprid such as the edge of the Treated Zone, disoriented the termites and caused them to cease their natural grooming behaviour. Grooming is important for termites to protect them against pathogenic soil fungi. When termites stop grooming, the naturally occurring fungi in the soil attack and kill the termites. Imidacloprid makes fungi 10,000 times more dangerous to termites. Nature assists imidacloprid in giving unsurpassed control. This control is called Premise 200SC plus Nature."

This subject is explored in greater depth in: how do neonicotinoids work to kill insects?