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Misconception Number 7: Organic farming uses pesticides that damage the environment: natural pesticides are more dangerous than conventional pesticides because they are less efficient and therefore require the application of huge quantities. This is also true for fungicide (e.g., organic grape producers contaminate the soils with large quantities of copper because they are not allowed to use modern fungicides). In addition, some organic pesticides are as poisonous as synthetic ones (e.g., nicotine and pyrethrum).
Summary of Counter-Arguments:
- Organic Agriculture relies first on preventive measures and only as a last resort on natural pesticides. Therefore, pesticide application is not routinely used as in conventional agriculture.
- Use of pure nicotine, as well as nicotine naturally present in tobacco tea, is forbidden by organic regulations of major organic markets including the US, the EU, and Japan.
- Pyrethrins break down quickly and are one of the least poisonous insecticides to mammals.
- Research is being undertaken to find alternatives to copper and, meanwhile, organic standards include restrictions on the quantity of copper salt applied to fields.
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Details of Counter-Arguments:
As explained in the answer
to misconception number 43, natural molecules (such as those present in
natural pesticides) can be very toxic for certain species (e.g., they are
used as natural pesticides to kill certain insects), but are not toxic for
the environment as a whole because other species can digest them without
problem and they do not accumulate in the environment or food chain.
Pure nicotine is not allowed in Organic Agriculture. Nicotine found
in tobacco tea is also forbidden in some organic standards.However, tobacco tea is permitted under other
organic standards because it is a plant extract produced on-farm and the concentration of nicotine in tobacco tea is
typically low, meaning only minute quantities of nicotine are actually
applied. In addition, this nicotine breaks down very rapidly in the
environment. The use of tobacco tea or other home-brewed pesticides
allows the farmer to be less dependent on manufacturers and traders of
pesticides, which is particularly important in third world countries. Moreover,
the toxicity of tobacco tea is considerably lower than the one of nicotine
sulphate (the product that is commercialized). Nicotine
sulfate is manufactured by combining nicotine from natural tobacco waste
with sulfur, resulting in a very toxic and dangerous substance. Homemade
tobacco teas do not result in this same toxic substance. While the acute
toxicity of nicotine (present in tobacco tea) is still quite high and
hence hazardous for the person that comes into direct contact with the
spray, the residual period, on the contrary, is short. This means that the
farmer has to protect himself well when using the product, but that the
product is not hazardous for the consumer. Nevertheless, many organic
regulations forbid the use of certain natural pesticides (on-farm produced
plant extracts) when their toxicity is controversial. Hence, pure nicotine, as well as nicotine
naturally present in tobacco tea, is forbidden by organic regulations of
major organic markets, including those of the US,
the EU, and Japan.
Pyrethrins are natural insecticides produced by certain species of
the chrysanthemum plant. Pyrethrins
are one of the least poisonous insecticides to mammals because they are
quickly broken down into inactive forms and pass from the body in urine
and feces. [1] The
main environmental problem with pyrethrins is their toxicity to aquatic
life, but the likelihood of them reaching and persisting in water bodies
is low because they have an extremely low pesticide movement rating since
they bind tightly to the soil and they rapidly degrade in sunlight at the
soil surface and in water. Hence pyrethrum, like other natural pesticides,
appears much less toxic than most synthetic pesticides.
Mineral inputs used in Organic Agriculture should contain as few
heavy metals as possible. Due to the lack of any alternative, and
long-standing, traditional use in Organic Agriculture, copper and copper
salts are exceptions for the time being. However, the organic sector is
aware of the risk of dependence on copper for pest management and control.
Research is underway to find
acceptable biological alternatives and disease management strategies to
replace the use of copper in the long run. More research is needed,
but already some promising alternatives have emerged, such as potassium
bicarbonate, which occurs in nature and is an effective fungicide that is
safe for humans and the environment. Research has also shown that milk
by-products and milk waste can be very effective in controlling moulds and
fungi. Other research is being done on how to bring in beneficial
micro-organisms that will attack fungal diseases. In the meantime, many certifiers put restrictions on
the use of copper salts (often limited to 3kg/ha per year on a rolling
average basis) and/or require that, if farmers are using copper, they are
required to conduct soil tests to make sure there is no copper toxicity.
In any case, Organic Agriculture
relies first on preventive measures and only as a last resort on natural
pesticides to control pests and diseases in crop production. If there
is a pest outbreak despite these preventive measures, organic farmers
typically use natural pesticides wisely, so as to disturb natural equilibrium
as little as possible.
[1] Ray, D.E (1991). Pesticides derived from plants and other organisms. In W.J. Hayes, Jr. & E.R. Laws (Eds.), Handbook of Pesticide Toxicology. Vol. 2. (pp.585-593). Toronto: Academic Press.
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