"Long before it's in the papers"
March 15, 2012

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Pesticide linked to bee die-offs

March 15, 2012
Courtesy of the American Chemical Society
and World Science staff

New re­search has linked spring­time die-offs of much-needed hon­ey­bees — part of a mys­te­ri­ous mal­a­dy called col­o­ny col­lapse dis­or­der — with a tech­nol­o­gy for plant­ing in­sec­ti­cide-coat­ed corn.

The study ex­am­ined bee die-offs in Eu­rope, and did­n’t ad­dress wheth­er si­m­i­lar causes are be­hind bee die-offs that have also af­flict­ed the Un­ited States. The af­fect­ed bees are crit­i­cal for pol­li­nat­ing food crops.

The re­search ap­pears on the eve of spring plant­ing sea­sons in some parts of Eu­rope where farm­ers use the tech­nol­o­gy and wide­spread hon­ey­bees deaths have oc­curred. The study ap­pears in the jour­nal En­vi­ron­men­tal Sci­ence & Tech­nol­o­gy, pub­lished by the Amer­i­can Chem­i­cal So­ci­e­ty.

The re­search­ers, An­drea Tap­paro of the Uni­vers­ity of Pa­do­va in Ita­ly and col­leagues, said seeds coat­ed with so-called neon­i­coti­noid in­sec­ti­cides went in­to wide use in Eu­rope in the late 1990s. The pes­ti­cides are among the most widely used in the world, pop­u­lar be­cause they kill in­sects by par­a­lyz­ing nerves but have low­er tox­i­city for oth­er an­i­mals.

But al­most im­me­di­ate­ly, bee­keep­ers no­ticed large die-offs of bees that seemed to co­in­cide with mid-March to May corn plant­ing, the in­ves­ti­ga­tors said. Sci­en­tists thought this might be due to par­t­i­cles of in­sec­ti­cide thrown aloft by drill­ing ma­chines used for plant­ing. These ma­chines force­fully suck seeds in and ex­pel a burst of air con­tain­ing high con­centra­t­ions of par­t­i­cles of the in­sec­ti­cide coat­ing, ac­cord­ing to the re­searchers.

In an ef­fort to make the pneu­mat­ic drill­ing meth­od safer, the sci­en­tists tested dif­fer­ent types of in­sec­ti­cide coat­ings and seed­ing meth­ods. But they found that all varia­t­ions in seed coat­ings and plant­ing meth­ods killed hon­ey­bees that flew through the seed­ing ma­chine’s emis­sion cloud. One ma­chine mod­i­fied with a de­flec­tor to send the in­sec­ti­cide-laced air down­wards still caused the death of more than 200 bees for­ag­ing in the field. 

The au­thors sug­gest that fu­ture work on the prob­lem should fo­cus on a way to pre­vent the seeds from frag­ment­ing in­side the pneu­mat­ic drill­ing ma­chines.

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New research has linked springtime die-offs of much-needed honeybees — part of a mysterious malady called colony collapse disorder — with a technology for planting insecticide-coated corn. The study examined bee die-offs in Europe, and didn’t address whether similar causes are behind bee die-offs in the United States. The affected bees are critical for pollinating food crops. The research appears on the eve of spring planting seasons in some parts of Europe where farmers use the technology and widespread honeybees deaths have occurred. The study appears in the journal Environmental Science & Technology, published by the American Chemical Society. The researchers, Andrea Tapparo of the University of Padova and colleagues, said seeds coated with so-called neonicotinoid insecticides went into wide use in Europe in the late 1990s. The pesticides are among the most widely used in the world, popular because they kill insects by paralyzing nerves but have lower toxicity for other animals. But almost immediately, beekeepers noticed large die-offs of bees that seemed to coincide with mid-March to May corn planting, the investigators said. Scientists thought this might be due to particles of insecticide thrown aloft by drilling machines used for planting. These machines forcefully suck seeds in and expel a burst of air containing high concentrations of particles of the insecticide coating, according to the resaerchers. In an effort to make the pneumatic drilling method safer, the scientists tested different types of insecticide coatings and seeding methods. But they found that all variations in seed coatings and planting methods killed honeybees that flew through the seeding machine’s emission cloud. One machine modified with a deflector to send the insecticide-laced air downwards still caused the death of more than 200 bees foraging in the field. The authors suggest that future work on the problem should focus on a way to prevent the seeds from fragmenting inside the pneumatic drilling machines.