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G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
RISKS AND BENEFITS OF PESTICIDES
FOR
FUTURE GLOBAL FOOD DEMANDS
Dr. Gerry Stephenson
Department of Environmental Biology
University of Guelph
Guelph, Ontario, Canada
Gerry.stephenson@rogers.com
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Class Percent US Dollars (billions)
Herbicides 44 15.40
Insecticides 29 10.15 & acaricides
Fungicides 21 7.35
Nematicides 6 2.10plant growth regulators
Total 100 35
APPROXIMATE WORLD MARKET FOR CHEMICAL PESTICIDES
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
West Europe28.0%
Latin America 7.0%
Rest of World 7.0%
East Europe &Former USSR 8.0%
US 25.0%Asia 25.0%
W ORLD PESTICIDE MARKET
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03 Insecticides Fungicides Herbicides
Pe
rcen
t o
f W
orl
d U
se50
20
10
60
50
40
30
20
10
0
PERCENT OF W ORLD USE IN DEVELOPING COUNTRIES
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
North Americathousands of accidental poisonings each yearnumerous accidental deaths each year
World wide3 million reports of serious poisoning each year(how many are unreported?)220 thousand accidental deaths each yearincidence of health problems is 13 times higher in developing countrieschronic effects??
Donald J. Ecobicon, 1998
PESTICIDES CAN BE A RISK TO HUMAN HEALTH
(Particularly for pesticide applicators)
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
HEALTH RISKS WITH PESTICIDES
DEPEND ON
PESTICIDE and HUMAN TOXICITY EXPOSURE
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
More women are choosing research careers in agriculture
But this a poor illustration of how to dress when using a research sprayer
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Applicators of unregistered
pesticides in research
Should wear full protective clothing
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
In industrialized countries,
Most growers are trained and certified pesticide applicators
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Advances in sprayer technology are reducing risks
For the applicator and for the environment
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Especially in landscape situations
How much protective clothing is required for safety?
HAND-HELD PESTICIDE SPRAYERS ARE STILL USED IN NORTH AMERICA
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Pesticides are commonly applied with hand held sprayers in
“Developing countries”
Notice the bare skin, especially the hands!
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
HEALTH RISKS WITH PESTICIDES ARE A PREVENTABLE PROBLEM
•Proper pesticide use rarely causes a health problem
•Problems can be prevented by the continued development of even safer pesticides
•Industrialized countries have effective regulatory, educational and training programs for applicators
•These programs are expensive to maintain and will be a challenge to implement in developing countries
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
PESTICIDES CAN BE AN ENVIRONMENTAL RISK
Risk depends on
• volume of use
• persistence
• mobility
• non-target toxicity
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
EVIRONMENTAL CONCERNS ABOUT PESTICIDES
1960’s Today
Insecticides Herbicides
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
EVIRONMENTAL CONCERNS ABOUT PESTICIDES
Spray Drift
Early studies on 2,4-D drift
More recent studies on glyphosate or clomazone drift
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ENVIRONMENTAL CONCERNS ABOUT PESTICIDES
Early concerns about 2,4-D, atrazine, metolachlor
Less concern with new “low rate” pesticides
PESTICIDE CONTAMINATION OF WATER
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ENVIRONMENTAL CONCERNS ABOUT PESTICIDES
SOIL RESIDUE CARRY OVER PROBLEMS
Earlier studies with triazine herbicides
More recent concerns with sulfonylurea or imidazolinone herbicides
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
NEW LOW-RATE HERBICIDES (<100 g/ha)
•Are reducing environmental risks in general
•However, soil residue carry-over concerns
are environmental problems for the farmers
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ROTHAMSTEAD SOIL STUDY SHOWS EFFECTS OF PESTICIDES IN SOIL ARE REVERSIBLE
17 months after applying five pesticides per year for 20 years
• no detectable pesticide residues
• no differences in microbial activity
• no effect on barley yield, as indicator crop
Evans(IUPAC)1998
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BENEFITS OF PESTICIDES -TO WHOM?
_________________________________________
Numbers
Chemical companies Very small
Growers Small
Consumers Large
Society Vast
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
First Sales Patent Expiry
Direction of current pressures
Years0 10 15 20 25
100
80
60
40
20
0
-20
-40
-60
-80
-100
$10 6
TYPICAL CUMULATIVE DISCOUNTED CASH FLOW FOR A SUCCESSFUL
NEW PRODUCT
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BENEFITS OF PESTICIDES
-TO WHOM?
________________________________
Numbers
Chemical companies Very small
Growers Small
Consumers Large
Society Vast
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Growers expect a $4 return on each $1 spent on pesticides
Is this still true?
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BANNING PESTICIDE USE IN THE USA
•Would reduce agricultural output by 30%
•At pesticide & commodity prices in 1997
•There would be a $3 to $4 return for each $1
spent on pesticides
Fernandez-Cornejo et.al., 1998
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Governments in a number of industrialized countries have set goals for reducing the use of pesticides in agriculture
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
FOOD SYSTEMS 2002 IN ONTARIO, CANADA
OBJECTIVES
•To reduce total Kg of pesticide use by 50% by the year 2002
•While maintaining agricultural productivity
METHODS
•Improved grower education, IPM and development of more alternatives
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
FOOD SYSTEMS 2002
Reduction in Kg of agricultural pesticides between 1983 and 1998
•For all agricultural crops 38%
•For maize (our largest crop) 48%
Reasons
•Better grower education, IPM, alternatives
•Shift to new “low-rate” pesticides
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
DT = dermal toxicityC = chronic toxicitySY = system icityF = fish toxicityL = leaching potentialR = surface loss potential
EIQ = ( c [(DT*5)(DT*P)] + (C *((S+P)/2)*SY) + (L) +
(F*R) + (D*((S+P)/2)*3) + (Z*P*3) + (B*P*5) )/3
D = bird toxicityS = soil half-lifeZ = bee toxicityB = beneficial arthropod
toxicityP = plant surface half-life
(Kovach et al., 1992).
ENVIRONMENTAL IMPACT QUOTIENT (E.I.Q)
Farm worker risk Consumer risk
Ecological risk
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
FOOD SYSTEMS 2002
Reduction in E.I.Q./ha between 1983 and1998
For all crops 34%
For corn(maize) 40%
The next survey is for this year, 2003
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BENEFITS OF PESTICIDES
-TO WHOM?
________________________________
Numbers
Chemical companies Very small
Growers Small
Consumers Large
Society Vast
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Year Pesticide CropPurchased Value
Econom ic benefit of pesticide use assum ing10% increase in yield 30% increase in yield
($ x 10 ) ($ x 10 ) (crop $ (Per $ (crop $ (per $ x 10 ) pesticide) pesticide)
1973 113.1 3.32 287.2
1978 70.8 1802.4 163.9 2.31 415.9 5.87
1983 133.7 2642.4 240.2 1.80 609.8 4.56
1988 146.1 2599.8 236.3 1.62 600.0 4.11
1993 176.1 2765.3 251.4 1.43 638.1 3.62
1998 194.0 1.27 746.3
6
6
6
6x 10 )
34.1 1244.4 8.42
231.9 3234.1 3.22
ECONOMIC BENEFIT OF PESTICIDE USEIN ONTARIO AGRICULTURE
All data are in Canadian Dollars
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BENEFITS OF PESTICIDES
-TO WHOM?
________________________________
Numbers
Chemical companies Very small
Growers Small
Consumers Large
Society Vast
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
BENEFITS OF PESTICIDES
-TO WHOM?
________________________________
Numbers
Chemical companies Very small
Growers Small
Consumers Large
Society Vast
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
SOCIETAL BENEFITS MINUS COSTS OF PESTICIDE USE IN THE USA
•The annual use of $6.5 billion worth of pesticides
•Prevents $26 billion in crop losses due to pests
•About a $4 return per $1 spent on pesticides to the growers
Pimentel and Greiner, 1997
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
SOCIETAL BENEFITS MINUS COSTS OF PESTICIDE USE IN THE USA
•Estimated indirect costs of pesticide use is $8 billion per year (regulation, training, health & environmental losses)
•$26 billion in benefits/$14.5 billion in costs equals about a $2 return to society for each $1spent on pesticides
Pimentel and Greiner, 1997
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
AGRICULTURAL PESTICIDE USE
SAVES ENERGY
HUMAN ENERGY FOSSIL FUELS
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Nu
mb
er o
f p
eop
le f
ed b
y o
ne
farm
er
AGRICULTURAL EFFICIENCY IN RELATION TO ADVANCES IN W EED CONTROL
50
40
30
20
10
010,000B.C.handremoval
1
6,000B.C.hand tools
1.5
1,000B.C.anim alpower
3
1920A.D.tractorpower
8
16
1947A.D.chemicalcontrols
50
1985A.D.to presentday
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
PESTICIDES SAVE HUMAN ENERGYProportion of population involved in food production:
N. America 2% 1 in 50
Brazil 20% 1 in 5
Mexico 25% 1 in 4
World wide 45% 1 in 2
Kenya 70% 2 in 3*
*Mostly women and children.
African women spend half of their waking hours working in the fields
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ENERGY USE FOR GRAIN CORN (ZEA MAYS) PRODUCTION IN ONTARIO: 1975 VS. 1991
Energy Source Energy use (GJ/ha) % Change1975 1991 1975 vs. 1991
TillagePrimary 0.9 0.6 - 33.3Secondary 0.5 0.8 +62.5
Fertilizer mfg 14.4 8.3Herbicide mfg 1.8 0.8Herbicide appl 0.1 0.1 0.0Other 1.7 1.1 - 35.3Total 19.4 11.7
- 42.4- 55.6
- 39.7
(Swanton, Murphy, Hume & Clements, Ag Systems, 1996)
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ESTIMATED CONTRIBUTION OF CROP PROTECTION CHEMICALS TO WORLDWIDE PRODUCTION OF THE EIGHT
PRINCIPAL FOOD AND CASH CROPS (1990 vs 1965)
Oerke et. al., 1994
We harvest only 58% of the theoretical, world-wide yield
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Oerke, et. al., 1994
LOSSES DUE TO PESTS IN W ORLD MAIZE PRODUCTION BY REGION AND
OVERALL
Region % losses 1988-1990 due to Actual total Loss if NoDiseases Pests W eeds Loss Crop Protection
52.8
24.8
Africa 15.7 19.6 17.5 71.6Am ericas 9.7 12.3 13.3 35.4 57.9Asia 12.0 18.4 12.0 42.5 60.8Europe 6.4 9.1 9.3 51.9USSR 12.7 12.7 15.3 40.8 57.4Oceania 7.4 8.5 8.5 24.4 51.9
World 10.8 14.5 14.5 38.3 59.5
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
LOSSES DUE TO PESTS IN W ORLD W HEAT PRODUCTION BY REGION AND OVERALL
Region % losses 1988-1990 due to Actual total Loss if NoDiseases Pests W eeds Loss Crop Protection
26.541.8
Africa 7.6 12.2 20.1 39.9 53.2Am ericas 13.6 10.4 11.0 35.0 49.7Asia 13.5 8.9 15.2 37.6 50.8Europe 9.5 7.6 9.4 52.7USSR 17.0 10.2 14.4 55.4Oceania 17.2 10.3 11.2 38.6 60.7
World 13.3 9.3 13.1 35.7 51.9
Oerke, et. al., 1994
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
LOSSES DUE TO PESTS IN W ORLD RICE PRODUCTION BY REGION AND OVERALL
Oerke, et. al., 1994
Region % losses 1988-1990 due to Actual total Loss if NoDiseases Pests Weeds Loss Crop Protection
55.758.254.8
25.0
Africa 15.5 17.6 22.6 83.1Americas 22.3 14.6 21.4 86.4Asia 15.8 22.1 16.9 83.1Europe 9.3 13.0 13.7 36.1 74.5USSR 12.7 12.7 16.9 42.2 70.0Oceania 5.7 5.2 14.1 60.4
World 15.9 21.5 17.2 54.6 83.2
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
LOSSES DUE TO PESTS IN W ORLD SOYBEAN PRODUCTION BY REGION
AND OVERALL
Oerke, et. al., 1994
Region % losses 1988-1990 due to Actual total Loss if NoDiseases Pests W eeds Loss Crop Protection
42.8
20.2
Africa 14.0 12.7 16.1 70.1Am ericas 8.0 10.8 13.1 32.2 57.4Asia 14.5 13.3 11.8 39.5 64.9Europe 5.0 5.3 10.0 45.2USSR 13.0 10.4 13.0 36.4 58.2Oceania 13.2 8.8 10.6 32.7 59.2
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Year1960 1970 1980 1990 2000 2010 2020 2030
(431)
(415)
(316)
(251)
(200)
(158)
(126)
(100)
Index 1961 + 100)(Log Scale)
TRENDS IN DEVELOPING COUNTRIES GROSS AGRICULTURAL PRODUCTION
AND PRODUCTION CAPUT
K lassen (A C S ) 1995
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Mill
ion
Per
son
s
A frica (S . Sah)
S. A sia
N. East/ N . Africa
L. Am erica/ CaribbE. A sia
843
47
285
359
23
129
79/81
781
59
271
252
24
175
88/90
63740
202
7029
296
2010
1000
900
800
700
600
500
400
300
200
100
0
941
54
497
42
94
69/71
254
NUMBERS (MILLIONS)OF UNDERNOURISHED PEOPLE IN DEVELOPING COUNTRY REGIONS:
HISTORICAL AND PROJECTED TO 2010
K lassen (A C S ) 1995
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
“MANY PEOPLE ARE CONCERNED ABOUT
THE IMPACT OF
PESTICIDES ON THE ENVIRONMENT”
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
“MORE PEOPLE SHOULD BE CONCERNED ABOUT
THE IMPACT OF
AGRICULTURE ON THE WORLD ENVIRONMENT”
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
PESTICIDES HELP SAVE LAND
•Since 1960, world agricultural production has tripled on 6 million square miles of land
•We would need to find new land for agriculture equivalent to all the agricultural land in Brazil, EU and USA combined
Avery, 1997
•Advances in crop protection, breeding & fertility
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
“If agricultural pesticides had not been available since 1950, we would have already lost half of today’s forested land to food production”
Lester Brown, 2001
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
W O R LD PO PU LATIO N
TR EN D S
2
4
6
8
10
12
14
Bill
ions
16
18
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
0
200
400
600
800
1000
1200
1400
1600
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Mil
lio
ns
Source: U.S. Bureau of the Census, International Data Base. (September 17, 2003)
EXPECTED POPULATION TRENDS IN CHINA, 1950-2050
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
0
50
100
150
200
250
300
350
400
1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
Mill
ions
Japan
North Korea
South Korea
Indonesia
Source: U.S. Bureau of the Census, International Data Base. (September 17, 2003)
EXPECTED POPULATION TRENDS IN OTHER ASIAN COUNTRIES, 1950-2050
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
After 2050, will world population actually decline?
Or, will politicians encourage women to resume having three or more children to sustain a growth economy?
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
FOR MOST OF THIS 21ST CENTURY
•50% more people will need food (9 vs 6 billion)
•With industrialization, they may have 50% more buying power
•There will be a need for twice as much foodThompson,1998
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
IF DIETARY TRENDS IN JAPAN ARE A GOOD EXAMPLE
PEOPLE WILL CONSUME
•more soybeans,vegetables, fruits
•more dairy products
•more animal protein
•less rice, wheat, maize, sorghum
These trends will require much higher yields or more land for agriculture
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
HOW MUCH AGRICULTURAL LAND WILL THERE BE?
We may be able to increase agricultural land about 10% (S. America etc.)
However,
We may increase the amount of land used to produce fuel, fiber and other non-food crops
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
HOW CAN WE DOUBLE “NET” YIELDS OF FOOD CROPS AGAIN ON ABOUT THE SAME LAND AREA?
Oerke et. al.,
Can we achieve 90% instead of 60% of our theoretical yield?
(harvest 20% more and prevent 10% losses in storage)
Better pest controlthroughoutthe world?
50% MORE FOOD?
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
We need advances and better application of both,
INTEGRATED PEST MANAGEMENTand
CROP GENETICS
TO DOUBLE WORLD FOOD PRODUCTION
BY 2050
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
“Technically, this may be possible”
“Psychologically, it may be impossible”
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
THE MENTAL AFFLUENCE TRAP
“People’s willingness to accept change is inversely proportional to their affluence”
“This eventually leads to mental immobility for the affluent, who become critical of the new technology that was originally responsible for their affluence.”
“Conversely, the less affluent will readily accept change in an effort to improve their prosperity.”
Hans Mohr, Univ. Freiburg, 1990
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
THEREFOREPeople in developing countries will want to increase pesticide use to improve their standard of living
People in industrialized countries will want to decrease pesticide use and purchase more organic food to preserve their health and prosperity
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
DEVELOPING COUNTRIES WANT TO PRODUCE MORE FOOD FOR THEMSELVES AND HAVE SOME TO SELL TO OTHER COUNTRIES AS WELL
Developing countries will increase pesticide use
We must help them develop suitable regulations and training programs to prevent adverse health effects and environmental problems
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
CONCLUDING COMMENTS
I favor a 100% reduction in pesticide use when they aren’t needed to increase crop yields.
Is prohibiting “needed pesticide” use, morally correct in view of world food needs?”
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ORGANIC FARMING?
I would hate to see a large shift to organic farming in industrialized countries in an attempt by farmers to make more money by catering to the more affluent
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
A GOAL FOR THIS 21st CENTURY
TO PREVENT HUMAN HUNGER WITHOUT IRREVERSIBLE HARM TO
THE WORLD ENVIRONMENT
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
WORLD POPULATION
If world population peaks at 9 billion in 2050
and
declines to <6 billion during the 22nd century
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
Future generations may have the choice between organic farming or reducing land for agriculture
It would be very selfish and narrow-minded to think that we have that choice today!
BEYOND 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
The text of this talk was recently published as Chapter 15, in:
ACS Symposium Series 853,
American Chemical Society, Washington D.C., 2003
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
IM PACT OF CROP PROTECTION ON THE W ORLD PRODUCTION OF EIGHT PRINCIPAL FOOD AND CASH CROPS (1988-90)
Eight Actual Theoreticalm ajor w ith with no yields yield world no crop w ith crop increase crops losses protection protection w ith crop (tonnes x 1000) (tonnes x 1000) (% )
M ean increase 119
Theoretical crop yields
Rice 1087 184 520 182W heat 902 286 595 108Barley 253 134 180 34Maize 211 85 129 52Potatoes 466 121 275 127Soybeans 157 65 107 65Cotton 87 14 54 285Coffee 10 3 6 100
Developed from data by Oerke et. al., 1994
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
ENERGY USE FOR W EED MANAGEMENT IN SOYBEAN W ITH VARYING HERBICIDE INPUTS
Input Source Herbicide input (MJ/ha) systemsLow Minimum
Glyphosate 517 5172,4-D 176 176Imazethepyr 14 -Inter-row cultivation - 324 324Rotary hoeing - - 131
Totals 1031 1148
High
517176 33
726
(Swanton, Murphy, Hume & Clements, Ag Systems, 1996)
Years1950 1975 2000 2025 2050 2075 2100
G.R.S. Univ. Guelph
IUPAC – KSPS 13-10-03
FOR THE 10 MAJOR AGRICULTURAL STATES IN THE USA
Economic benefits of pesticide use to growers
declined
from $8 per $1 spent on pesticides in 1949 to
$4 per $1spent on pesticides in 1991
Teague and Brorsen, 1995
Recommended