Life and thoughts from a small-scale organic farm . . . and its farmers

This is a blog that explores ideas around the growing of food and community at Glen Valley Organic Farm.

Monday, June 28, 2010

Organic Pesticides

There is a new fruit fly in the Pacific Northwest that is causing berry producers someLink stress. Rather than being attracted to rotting produce, as with most fruit flies, the Spotted Wing Drosophila Fruit Fly lays its eggs in immature soft-skinned fruit. The eggs then hatch in maturing fruit, resulting in larvae in the mature fruit. Obviously, this has an impact on the marketability of the fruit.

Agriculture Canada is monitoring fields across the Lower Mainland and the Okanagan for this new fly. They have found some in our field. They are recommending that organic farmers use a biological insecticide produced by Dow AgroSciences called Entrust. Biological insecticides in some formulations are allowed in organic production because they are comprised of naturally-occurring bacteria which are cultivated for agricultural application. Pests ingest and are killed by this bacteria.

These products, nonetheless, can pose hazards, even when applied according to directions. The problem with Entrust is summarized best by the product's own label:
"This product is highly toxic to bees exposed to direct treatment, drift or residues on blooming plants. Do not apply this product or allow it to drift to blooming plants if bees are visiting the treatment area. This product is harmful to parasitoids and predatory mites and slightly harmful to foliage-dwelling predators. Care should be taken when using this product in an integrated pest management program where users are relying on the presence of beneficial arthropods.
"This product is highly toxic to aquatic invertebrates. Do not contaminate aquatic habitats, such as lakes, rivers, sloughs, ponds, coulees, prairie potholes, creeks, marshes, streams, reservoirs, and wetlands, when cleaning and rinsing spray equipment or containers.
"This product contains an active ingredient and aromatic petroleum distillates which are toxic to aquatic organisms."
Farmers are also being advised to remove wild berries from around their fields such as Salmon Berries, Thimble Berries and Blackberries.

How either of these solutions fits the notion of "organic" agriculture is beyond me.

There is increasing resentment toward organic growers in the agricultural community because many conventional farmers think it is the fault of organic growers that this fruit fly is spreading. We don't generally spray pesticides, so we must be the ones at fault.

In reality, the fact that berries have become the only show in town over the past 20 years is really what should be examined. Mono-cropping is a sure-fire way to cultivate new diseases and pests and allow for their rapid spread. To this point, chemical companies have tried to provide a technological "fix" to these problems. If you enter an agricultural supply store in Abbotsford, you only need to look at the weekly list of sprays and chemical fertilizers listed for berry crops to understand the formulaic nature of this industrialized system of agriculture.

The challenge to farmers and consumers is whether or not we can cultivate a sustainable food system that relies on more than berries to pay farmers and feed the public at large. Supporting small, diversified, organic farms is the solution, not the problem in such a scenario. I only hope that governments realize this before they further recommend the destruction of natural habitat and the application of pesticides that poison our bees, native insects and aquatic life.


  1. I work at a contract science lab, and we have tested something similar in the past, assuming you are talking about Bt. This formulation must be different, though, as the one we tested didn't have any petroleum in it, and if I recall correctly, did not have any adverse effects on fish or aquatic arthropods. It was something being developed out in New Brunswick for Natural Resources Canada.

    Unfortunately I can't give you the name of the product for obvious reasons, but that might be something to look into.

  2. I think we should all "entrust" our health into the knowing hands of the good people at Dow. Who needs bees anyway.

  3. Jeremy - Entrust is different from Bt, although both are biological insecticides. We do use Bt on our Brassica crops in the late summer when cabbage worms are at their worst. Bt must be used with care and only sprayed when necessary to avoid the development of resistance in pests and killing off other beneficial insects.

    Bt is also at the centre of concern around some new Genetically Modified crops. Corn and cotton are being bred so that Bt is present in the plant matter itself. Thus, not only is Bt present in the plant at all times (thus exposing all insects indiscriminately) but it also kills off soil organisms once the crop is plowed under.

    Entrust, which is being recommended for the new fruit fly, is difficult to use in the ways being recommended. For example, if we were to spray wild berries around our fields, we would be spraying the salmon berries and thimble berries now while the blackberries are flowering. And that means exposing bees to the insecticide when they are most attracted to these buffer areas.

    It will be interesting to see what berry crops will be like in the future.

  4. Organic pesticides are the best option whether we use them for our backyard garden or a large piece if land.
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