Saving the Honeybee Through Organic Farming

Professor Joe Cummins

Synergistic effects of pesticides and parasitic fungi and worsening decline of honeybees
The decline of the honeybee attracted worldwide attention in 2007. Investigations carried out by the Institute of Science in Society implicated a synergistic interaction between the recent widespread use of new pesticides (including Bt toxin from GM crops) and fungal infections [1, 2] (Parasitic Fungus and Honeybee Decline , Parasitic Fungi and Pesticides Act Synergistically to Kill Honeybees?, SiS 35). Sub-lethal levels of neonicotinoid pesticides act synergistically with parasitic fungi in killing insects pests. Fungal spores, widely used as biocontrol agents are applied in sprays and baits, and when delivered in suspension with sub-lethal levels of pesticides are much more effective in killing insects. Equally, Bt biopesticides enhance the killing power of parasitic fungi synergistically. That information was transmitted through a written question to the European Parliament [3].

Last year’s decline was serious enough and described as “beepocalypse now” by a news report [4]. According to the US Department of Agriculture one mouthful in three of the foods we eat directly or indirectly depend on pollination by honeybees [5]. Most fruit and many vegetables would disappear from our diet along with an immediate shortage of meat due to the loss of forage. This winters’ bee loss was 34 percent, up from the 25 percent the previous year [6].

The decline is attributed to ‘Colony Collapse Disorder’ (CCD), most likely to be multi-factorial. The main suspects include pesticides, parasites, viruses, radiation from cell phone transmitters [7-9] (Mystery of Disappearing Honeybees, Requiem for the Honeybee, Mobile Phones and Vanishing Bees, SiS 34) and even brood temperature [10]. The impact of sub-lethal levels of pesticides on the immune system of the bee leads to synergistic infection of the bees by fungal parasites. In addition, the behaviour of the bees is frequently modified leading to confusion in foraging and failure to return to the hive.

Organic farming practices that retain more natural habitats and avoid the use of chemical pesticides should provide environments that serve as honeybee sanctuaries from the ravages of CCD. There are scientific studies showing that agricultural landscapes with organic crops are far superior environments for both honey- and bumblebees [11, 12]. It would be prudent to create organic bee sanctuaries as widely and as soon as possible.

Fungal infections more deadly with increased carbon dioxide in the atmosphere
With regard to the fungal parasites, it was recently shown that the prominent fungal parasite Nosema ceranea has been a longstanding and widespread infection of honeybees in the United States [13]. Nosema ceranae was detected also in Canada [14]. Spores of a related parasite, Nosema apis, was found to respond to increased carbon dioxide in the atmosphere by enhanced germination, resulting in higher mortality of infected bees [15]. Will global warming result in the honeybee losing its struggle with fungal parasites?

Sub-lethal effects are the silent killers
The sub-lethal effects of insecticides go beyond the synergistic effect of insecticides on the immune system, as they may also affect learning and foraging competence of the honeybee, A recent study from France showed that bees fed sub-lethal levels of Bacillus thuingiensis Cry1Ab protein (a toxin in MON810 maize) affect food consumption and or learning processes leading to disturbed foraging [16]. The neonicotinoid pesticides that also affect bees in similar ways [2] are used extensively as systemic insecticides, and frequently originate from seed treatment. One member of that group, Imidacloprid, was tested extensively, leading to its ban in France, Another of the neonicotinoid pesticide, Acetamiprid, was found to impair olfactory learning in the honeybee while the pesticide Thiamethoxam did not appear to effect bee behaviour [17]. The regulation of insecticides should definitely be extended to include sub-lethal behavioural impairment of the honeybees, and those insecticides having such an effect should be banned immediately. A risk assessment to honeybees was developed in France for non-sprayed (seed treatment) systemic chemicals [18], though predictably industry representatives argued that field test data should override trials on sub-lethal effects [19]. Along those lines, industry and its associated academics selected and reviewed 25 laboratory studies showing that Bt toxins including Cry1Ab have no adverse effects on honeybees [20], but the only adverse outcome considered was mortality directly due to the pesticide, excluding learning impairments that could also result in the bees dying. Unfortunately, regulatory agencies appear to be similarly impaired when it comes to recognizing evidence related to sub-lethal impairment of the bees.

Organic agriculture must be widely adopted to save the honeybee
In conclusion, sub-lethal levels of pesticides, including the Bt biopesticides produced in genetically modified (GM) crops covering some 30 percent of the global area, disorientate the bees, making them behave abnormally, and compromise their immunity to infections. Regulators have allowed the widespread deployment of systemic neonicotinoid pesticides based on assessments of lethal dose in bees of the pesticides alone, ignoring clear evidence that sub-lethal pesticide levels act synergistically with fungal parasites in killing insects. The honeybees may well be succumbing to such synergistic effects. There is every reason to eliminate the use of all pesticides that act synergistically with parasitic fungi, and all Bt crops should be banned for the same reason. Obviously, these problems will disappear with the widespread adoption of organic, non-GM farming.

Opinion: Did your shopping list kill a songbird?

By BRIDGET STUTCHBURY

THOUGH a consumer may not be able to tell the difference, a striking red and blue Thomas the Tank Engine made in Wisconsin is not the same as one manufactured in China — the paint on the Chinese twin may contain dangerous levels of lead. In the same way, a plump red tomato from Florida is often not the same as one grown in Mexico. The imported fruits and vegetables found in our shopping carts in winter and early spring are grown with types and amounts of pesticides that would often be illegal in the United States.

In this case, the victims are North American songbirds. Bobolinks, called skunk blackbirds in some places, were once a common sight in the Eastern United States. In mating season, the male in his handsome tuxedo-like suit sings deliriously as he whirrs madly over the hayfields. Bobolink numbers have plummeted almost 50 percent in the last four decades, according to the North American Breeding Bird Survey.

The birds are being poisoned on their wintering grounds by highly toxic pesticides. Rosalind Renfrew, a biologist at the Vermont Center for Ecostudies, captured bobolinks feeding in rice fields in Bolivia and took samples of their blood to test for pesticide exposure. She found that about half of the birds had drastically reduced levels of cholinesterase, an enzyme that affects brain and nerve cells — a sign of exposure to toxic chemicals.

Since the 1980s, pesticide use has increased fivefold in Latin America as countries have expanded their production of nontraditional crops to fuel the demand for fresh produce during winter in North America and Europe. Rice farmers in the region use monocrotophos, methamidophos and carbofuran, all agricultural chemicals that are rated Class I toxins by the World Health Organization, are highly toxic to birds, and are either restricted or banned in the United States. In countries like Guatemala, Honduras and Ecuador, researchers have found that farmers spray their crops heavily and repeatedly with a chemical cocktail of dangerous pesticides.

In the mid-1990s, American biologists used satellite tracking to follow Swainson’s hawks to their wintering grounds in Argentina, where thousands of them were found dead from monocrotophos poisoning. Migratory songbirds like bobolinks, barn swallows and Eastern kingbirds are suffering mysterious population declines, and pesticides may well be to blame. A single application of a highly toxic pesticide to a field can kill seven to 25 songbirds per acre. About half the birds that researchers capture after such spraying are found to suffer from severely depressed neurological function.

Migratory birds, modern-day canaries in the coal mine, reveal an environmental problem hidden to consumers. Testing by the United States Food and Drug Administration shows that fruits and vegetables imported from Latin America are three times as likely to violate Environmental Protection Agency standards for pesticide residues as the same foods grown in the United States. Some but not all pesticide residues can be removed by washing or peeling produce, but tests by the Centers for Disease Control show that most Americans carry traces of pesticides in their blood. American consumers can discourage this poisoning by avoiding foods that are bad for the environment, bad for farmers in Latin America and, in the worst cases, bad for their own families.

What should you put on your bird-friendly grocery list? Organic coffee, for one thing. Most mass-produced coffee is grown in open fields heavily treated with fertilizers, herbicides, fungicides and insecticides. In contrast, traditional small coffee farmers grow their beans under a canopy of tropical trees, which provide shade and essential nitrogen, and fertilize their soil naturally with leaf litter. Their organic, fair-trade coffee is now available in many coffee shops and supermarkets, and it is recommended by the Audubon Society, the American Bird Conservancy and the Smithsonian Migratory Bird Center.

Organic bananas should also be on your list. Bananas are typically grown with one of the highest pesticide loads of any tropical crop. Although bananas present little risk of pesticide ingestion to the consumer, the environment where they are grown is heavily contaminated.

When it comes to nontraditional Latin American crops like melons, green beans, tomatoes, bell peppers and strawberries, it can be difficult to find any that are organically grown. We should buy these foods only if they are not imported from Latin America.

Now that spring is here, we take it for granted that the birds’ cheerful songs will fill the air when our apple trees blossom. But each year, as we continue to demand out-of-season fruits and vegetables, we ensure that fewer and fewer songbirds will return.

Bridget Stutchbury, a professor of biology at York University in Toronto, is the author of “Silence of the Songbirds.”