Title: National Center for Food and Ag. Policy
1The Benefits of Agrochemical Research
Case Study of Imidacloprid
Sujatha Sankula Leonard Gianessi
National Center for Food and Ag.
Policy Washington, DC
2Agrochemical categories
Herbicides (47) Insecticides (29) Fungicides
(18) Fumigants growth regulators (6)
3Agrochemicals are necessary to
? Prevent yield losses ? Ensure quality ? Make
crop production easier cheaper
4Crop yield response to agrochemicals
Without agrochemical use With agrochemical use
Theoretical attainable yield
5Area farmed globally for food production in 2000
Billion ha
6Global value of agrochemicals in 1998
31.25 billion (crop uses) 10.5 billion
(non-crop uses)
7Worldwide crop protection markets in 2001
Sales in mil.
8 Goal of agrochemical research
- To discover, develop, and understand new
products for the safe and effective pest control
and to maximize food production
9 Agrochemical discovery development programs
are driven by
- Population growth
- Food and health needs
- Pest resistance issues
- Safety considerations
- Economic incentives
- Replacements and phase-outs
10 Recent setbacks to agrochemical discovery
programs
- Fewer players
- Large investments
- Great risks
- High stakes
- Economics
- Higher standards of potency and safety
11Insecticide categories
Organic (eg. DDT, chlorpyriphos) Botanicals (eg.
pyrethrum, nicotine) Inorganic (eg. boric acid,
sulfur)
12Market dominance of commercial insecticide
categories
Category
Inorganics
8 Botanical 5 Synthetic organics
192
13Major insecticide classes by importance as of 1995
Class Entry year Market
value
()
Chlorinated hydrocarbons 1947 5
Organophosphates 1965 34
Methylcarbamates 1969 20
Pyrethroids 1979 23 Benzoylureas 1983
5 Others 1982
8
14Human toxicity and insect resistance to the first
generation neuro-active insecticides such as
carbamates and OPs led to the search for new
agrochemicalsSignificant discovery -
Imidacloprid
15Imidacloprid
Classification Chloronicotinyl First registered
insecticide in its class Year
of registration in US 1995
16World sales of top selling pesticides in 2001
Glyphosate 2.4 billion Imidacloprid 540
million
Source PANUPS 2002
17Structural comparison of nicotine and imidacloprid
18Characteristics of imidacloprid
Novel mode of action Broad spectrum of
activity Favorable environment fate
19Mode of action of imidacloprid
Binds to nerve receptors called nicotinic
acetylcholine receptors (nAChRs), interferes
with the transmission of stimuli in the insect
nervous system leading to the accumulation of
acetylcholine resulting in paralysis.
20- Site of action is different than other
insecticides - to which insects developed resistance.
- Low toxicity to vertebrates due to low binding
- to nACh receptors.
21Imidacloprid provides a broad spectrum of
activity against
Sucking insects (leaf and plant hoppers, aphids,
thrips, whiteflies, scales, and plant
bugs) Some coleopteran insects (CPB, leaf
beetles) Select lepidopteran and dipteran
insects No activity on mites and nematodes
22 Imidacloprid has both contact and systemic
action. Imidacloprid can be applied as a
soil, seed, or foliar treatment. Readily
absorbed by plant roots and transmitted through
xylem. Effective at low rates than conventional
insecticides (0.33 lb versus 1-2 lb of OPs)
23Trade names of imidacloprid
Gaucho (seed treatment) Admire (soil
applied) Provado (foliar)
24Use range of imidacloprid
Potato Apple Tomato Grape Broccoli Citrus Le
ttuce Corn Sugarbeet Hops Cotton Rice Tobac
co
25Impacts of imidacloprid on US crop production
26Silverleaf whitefly
First discovered in 1986 in FL Widespread damage
in 1991 in CA and AZ Reduction in planted crop
acreage Yield and quality losses transmits
viruses (ToMoV and YLCLV)
27Silverleaf whitefly is a billion dollar pest
28Primary hosts of silverleaf whitefly
Broccoli Cauliflower Cabbage Lettuce Melons Cucumb
ers Tomatoes Cotton
29Silverleaf whitefly management
Three classes of effective insecticides
(pyrethroids, OPs, chlorinated
hydrocarbons) Most common combination
bifenthrin endosulfan (2-3) fb. esfenvalerate
endosulfan (1-3) No residual control and
periodic treatments (4-6 sprays) Insect
resistance to three chemical classes
30Section 18 permits for imidacloprid
(Admire) in California
First issue
Reissue
Broccoli/Cauliflower 1993 1994 Lettuce 1993
1994 Cucurbits 1995 1997 Tomatoes 1994
-
31Vegetable production statistics for CA
2001 Acreage ( of US total)
Broccoli 92 Lettuce 71 (head) 88
(leaf) Cauliflower 89 Tomato 32 (fresh) 92
(processed) Cantaloupe 58
32Use of imidacloprid (Admire) in California in 1995
treated acreage
33Impacts of imidacloprid (Admire) on
CA crop production
34Number of insecticide applications with Admire
and next best alternative
treatments
35Cost of insecticide programs with Admire and next
best alternative
Cost of programs ()
36Yield increase due to Admire compared to
traditional alternatives in CA
yield increase
37Value of delayed planting
Warm weather heavy whitefly pressure Growers
shift the planting date to cooler periods to
avoid peak infestations Imidacloprid
facilitated marketing at the height of
infestation
38Increase in grower benefits due to delayed
planting facilitated by Admire
increase
39 Impact of imidacloprid on insecticide use
in FL fresh tomato for whitefly and other
sucking pest control
1992
2000
------------- lb --------------
Buprofezin - 2000 Chlorpyrifos 22,0
00 - Endosulfan 89,000
34,900 Esfenvalerate 5,700
2,200 Imidacloprid -
8,400 Methamidophos 74,500
9,100 Methomyl 47,100
- Permethrin 10,900 8,000 Total 249,200
64,600
40Colorado Potato Beetle
41Green peach aphids
42Insecticide use CPB/aphids
- 1920s - 1940s Lead arsenate
- 1950s - 1960s DDT, Parathion,
- Endrin
- 1970s - Present Aldicarb, Phorate,
- Methamidophos,
- Carbofuran,
- Endosulfan
- Permethrin
43CPB management problems
CPB resistance to all synthetic insecticides
registered for use Cross-resistance of CPB
between insecticide classes Imidacloprid
unrelated chemistry and thus a new tool in
resistance management programs
44Imidacloprid treated potato acreage () in 1999
Idaho 8 Maine 90 Michigan 93 Minnesota 70
North Dakota 68 Oregon 35 Pennsylvania 81 Was
hington 4 Wisconsin 74
45Leading insecticides used for CPB control in 2001
(in order of importance)
Imidacloprid Carbofuran Permethrin Phorate Esfenva
lerate Endosulfan Methamidophos Azinophos-methyl A
ldicarb Methyl parathion Dimethoate
46Reduction in insecticide use following
imidacloprid use in potato (1994 1999)
reduction
Source NASS
47Pierces disease on grapes
48Sharpshooters
Bluegreen
Glassy-winged
49Pesticides registered for sharpshooter control
Average use rate (lb/A)
Dimethoate 1.32 Kaolin 23.75 Imidacloprid
0.05 (Admire)
50Other grape insects controlled by Admire
Grape mealybug Vine mealybug Leafhopper Phylloxera
51Insect management problems in citrus in CA and FL
Glassy-winged sharpshooter (overwintering
host) California red scale ( resistant to OP
carbamates) Citricola scale (increasing in
problem) Brown citrus aphid (vectors citrus
tristeza virus)
52Use of imidacloprid on citrus(Section 18 in CA
and FL)
Glassy-winged sharpshooter CA red scale Citrus
brown aphid Citrus leaf miner
53Cotton pest problems
Escalation of secondary pest problems Insecticide
resistance
54Losses due to aphids in CA cotton in 1997
Crop loss Control costs Aphids 34 3
8 All insects and mites 66 167
--------------- Million -----------------
55Imidacloprid treated cotton acreage in California
treated acres
Source NASS
56Summary
Sucking pests have not been a significant problem
to growers in the recent years, largely because
of the advances in agrochemical research that
resulted in the development of imidacloprid. Amer
ican growers were able to increase crop
yields, reduce crop production costs, and
insecticide use following the introduction of
imidacloprid. No agrochemical is immune to
problems.
57Conclusions
With the increasing safety and environmental
concerns, there will be loss of some
agrochemicals. Search for replacement products
that can live up to both regulatory and grower
standards necessitates continued agrochemical
research. Agrochemical research should
continue to meet the increasing demands of
growing population. Continued agrochemical
research will provide solutions to evolving pest
and their management problems.
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