Winter, 1992 (v5n2)
Pimentel, D., D. Andow, R. Dyson-Hudson,
D. Gallahan, S. Jacobson, M. Irish, S. Kroop, A. Moss, I. Schreiner, M.
Shepard, T. Thompson and B. Vinzant
In Pimentel, D.,
(ed.) Handbook of Pest Management in Agriculture, Vol.1. CRC Press,
Boca Raton, FL. pp.679-718. 1991
Can pesticide use be reduced
without substantial increases in food costs? This is the question David
Pimentel addresses in new research published in the 1991 edition of the
Handbook of Pest Management in Agriculture. A condensed version
of the same article appears in the June 1991 edition of BioScience (pp.402-409).
Pimentel concludes that a
50 percent reduction in pesticide use can be achieved with a total price
increase in purchased food of only 0.6 percent. The reduction in pesticide
use would involve "substituting currently available biological, cultural,
and environmental pest-control technologies for some current pesticide
control practices." Because this conclusion undercuts the argument
that pesticides are necessary to keep consumer food costs low, it is being
cited frequently by advocates of sustainable agriculture.
Methodology
Pimentel begins by noting
that farmers spend approximately $4.1 billion on pesticides annually.
They justify this high cost by a direct dollar return of from $3 to $5
for every $1 spent on pesticides. This cost ratio does not include the
indirect costs of pesticide use on human and environmental health, nor
does it take into account evolved pesticide resistance or the creation
of secondary pest problems. Because calculating the costs of these indirect
costs is extremely complex, it is difficult to calculate the net benefit
to farmers or to society of pesticide use. (For one such methodology,
see the review of Paying the Farm Bill in Components, 2(3),
Summer 1991, pp. 1-3.)
Pimentel's objective is to
document whether a 5O percent reduction in pesticide use can be achieved
without yield decreases due to increased crop losses to pests. He admits
that obtaining accurate crop loss data is difficult. Experimental field
tests often exaggerate crop loss because assessments of insect, weed,
and disease losses are carried out separately and then combined. (Using
this approach one study found a total crop loss on untreated apples of
more than 140 percent!) In other cases, data simply do not exist and must
be extrapolated from closely related crops. With these limitations in
mind, Pimentel characterizes his effort as a "first approximation"
and calls for better data collection in the future.
To arrive at his conclusion,
Pimentel looks at 40 major crops, concentrating on two crops for each
type of chemical: corn and cotton for insecticide use, apples and potatoes
for fungicides, and corn and soybeans for herbicides. For each crop he
considers the alternative pest control strategies already available for
the crop, their cost comparison with pesticide use, and any impact they
have on crop yields. He then calculates the total percentage decrease
in pesticide use possible and the effect of this decrease on the cost
of production.
Improved monitoring and application
equipment alone account for much of the total reduction Pimentel believes
is possible. For example, he notes that fungicide use on apples could
be reduced 10 percent by monitoring and better forecasting of disease
based on weather data, and another 10 percent by employing a recent design
in spray nozzle and application equipment.
By totaling the combined reductions made possible by substituting non-chemical alternatives on 40 major crops, Pimentel argues that a 50 percent reduction in agricultural pesticide use can be obtained in the near future. The total cost of implementing the alternatives is estimated to be approximately $1 billion. This would increase total pest control costs by approximately 25 percent, while increasing total food production costs at the farm by 0.6 percent.
Reviewer's Comments
The data limitations facing
Pimentel (or any other researcher in this field) make it difficult to
grant conclusions much validity. The 0.6 percent figure Pimentel reports
suggests a degree of precision that Pimentel himself is quick to dismiss
in the article. Advocates of sustainable agriculture should be careful
to treat Pimentel's work not as a definitive but a suggestive statement.
On the other hand, Pimentel's
conclusion is consistent with previous studies indicating that pesticide
bans or reductions would increase annual food costs to consumers by less
than 10 percent. Many consumers would be willing to pay these additional
costs, especially if they were understood as simultaneously decreasing
the social, environmental, health, and political costs associated with
pesticide use.
Two deeper issues are not
addressed in Pimentel's research. One is the fact that food prices are
largely determined by processors, wholesalers and retailers, after
food leaves the farm gate. Pimentel's work erroneously implies a direct
link between on farm production costs and the price the consumer pays
for food.
The second issue is that
pesticide reduction strategies inevitably impact much more than the practices
of farmers or the price of food. Pesticide use is linked to a broad range
of social, economic, and political issues, among them: government policies
to promote cheap food and export earnings; the growth of large agribusiness
entities through which farmers could (from the same company) purchase
various farm inputs and supplies, obtain advice and recommendations, and
in some cases, market their product; the sources farmers trust for information;
and, farmers' predisposition to avoid risk. These broader issues must
be examined to fully understand the root causes of pesticide use and abuse.
For more information write
to: D. Pimentel, College of Agriculture and Life Sciences, Cornell University,
Ithaca, NY 14853.
(DCC.003)
Contributed by David Campbell
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