News | February '10 | Pesticide argument
The
pro- and anti-GM factions started
an interesting debate recently.
A
private research firm contracted by
the biotech industry to supply data on pesticide usage suggested that
GM crops are associated with reduced applications. Its data
collection methods are unknown, but are described by one firm of
consultants (also contracted by the biotech industry) as “the
only
comprehensive source of pesticide use data”.
During
biotech PR campaigns,
information on pesticide usage is supplied by the (part
industry-funded) National Center for Food and Agriculture Policy
(NCFAP). This organisation bases its estimates of pesticide use on
the best pesticide-management systems recommended by university
scientists.
Another
side of the debate comes from
the US Organic Center which looked at data published by the US
government National Agricultural Statistics Service (NASS). The NASS
makes annual surveys of important crops by sending enumerators out
into the field to observe the amounts of pesticides farmers are
actually spraying. Since cuts in the Services' funding by the Bush
administration in 2002, not all crops are sampled in every year:
there are holes in the figures and the most important data for recent
years are missing.
The
conclusions reached by all these
estimates are very different. In the case of herbicide-tolerant
corn, for example, they range from an impressive more than 22%
reduction
of herbicide use on
GM compared with conventional crops, to a slight, nearly 1% increase.
OUR COMMENT
Very
typically for
a GM debate, we seem to be trying to compare and contrast guestimates
based on undefined methodologies, best-scenario theories, and real
data with more holes in them than a sieve.
Also
as seems the norm, information paid for by industry shows
industry products in a much better light than the independent
investigations come up with.
We're
all agreed we want to use fewer
pesticides on crops: the farmer wants less expense and work, the
consumer wants to eat less toxins, environmentalists want less damage
to wildlife, and the biotech industry wants good press for its
products. But, at the basis of the debate lies the measurement of
pesticides. How is the 'amount' of a pesticide actually measured?
How
do you 'compare' two completely
different chemicals, or worse two different cocktails of chemicals?
How do you compare a chemical designed to kill insects with one
designed to kill weeds? How do you compare a chemical produced by
the plant itself with a chemical sprayed on the soil and on the plant
and blowing in the wind?
The
conventional method of comparison
uses the weight of the active ingredient. In this way a highly toxic
compound might well count as lower usage than a less toxic one.
Adjuvant chemicals which are not considered 'active' ingredients but
can increase toxicity many fold are not included. Persistence of
toxins which can increase the duration of damage, the spread of
damage, and the toxicity if it accumulates, are not in the picture at
all.
Are
you getting the impression by now
that industry talk of reduced pesticide use might be something of a
PR stunt? The weight of active chemical sprayed may well be less for
GM crops which generate their own insecticide, but the amount of
toxic pesticide on your plate could be considerably more. Plants
designed to resist herbicides may only be sprayed once, but they're
also designed to absorb and accumulate the chemical, and so may well
contain more toxic pesticide than conventional crops which can't
tolerate such sprays.
What's
a sensible way to measure
pesticide use?
Farmers
need to know the level of
pesticide use in practical terms such as cost, the number of sprays
needed and precision of timing required. Environmentalists need to
know the level of pesticide use in terms of its toxicity and spread
in the environment. Information based on the weight of active
ingredient is of limited use to either sector and could be highly
misleading.
Consumers
need to know the toxic
effects of whatever final cocktail of applied pesticides,
plant-generated toxins and adjuvants they are actually eating. These
last data can only be derived from the testing of whole-foods as
eaten, not
from what some of the
individual components weighed before they reached the crop.
The
biotech
industry PR gurus must love data based on the weight of active
ingredient: the measure can easily be used to link GM crops with less
use of pesticides. Why complicate the picture by factoring in
toxicity?
The
moral is don't get side-tracked
into 'debates' about irrelevant data. Pesticides are toxic, and the
only purposeful way to assess them must factor in the toxicity of
what ends up in the environment or on your plate.
For
a more realistic take on the
problems caused by pesticides (and nothing to do with the weight of
active ingredient), see WEEDS
HAVE TRICKS UP THEIR SLEEVES and
SWAPPING
DISEASES – News, February 2010.
SOURCES
GM Crops Increase Herbicide Use in the United States, Institute of Science in Society Report, 18.01.10