Transcript Pest control

Pest Control
L7
English in Natural Science
自然科学の英語
2006
自然科学の英語-ENS-L7
Definitions
• Pest: animal species that interferes with human
activities
• Weed: a plant ‘pest’
• Pest control: reduction of pest/weed populations
to not damaging levels
1. Damage is
measured in
economic terms
§ Eradication (pest
extinction) is
practically
impossible
2006
自然科学の英語-ENS-L7
Control of pest/weeds
light
more crop yield
Disease
Weeds
Crop
Insects
losses
Storage
Total
water
crop pests
weeds crop
diseases
* Rice 16.2% (Crammer, 1967)
harvest
yield
Market yield
storage pests
nutrients
2006
12%
13
13*
20
48%
自然科学の英語-ENS-L7
Integrated Pest Management (IPM)
• Use all methods of control in a scientific
manner to reduce crop damage due to pests,
weeds and diseases
• Strategies
– Natural control: natural enemies
– Biological control: introduced predators,
parasites or diseases; reproductive control
– Agronomic control: crop rotation, strip cropping,
burning, mulching,
– Pesticides: treatment with chemical poisons
2006
自然科学の英語-ENS-L7
Agronomic control
• Crop rotation
– Change conditions for
pest development
– Based on life cycles
• Strip cropping
– Protect and foster
natural enemies
– Lower pest densities
• Burning of crop
residues
– Destroy pest larvae
– Re-start from scratch secondary succession
• Mulching
– Avoid weeds
• Light competition
• Chemical allelopathy
Sustainable solutions (1-3 years)
Require continuous use
Alone or combined
2006
自然科学の英語-ENS-L7
Biological control
Long-term solutions
Sustainable
Increase of predatory
populations
(After Van der Bosch et al. 1982)
• Scientific basis
– Each pest has natural predators, parasites and
competitors
– Bring equilibrium predator-prey below the economic
threshold of pest
2006
自然科学の英語-ENS-L7
Efficacy of biological control
Cottony-cushion scale
(Icerya purchasi, Hemiptera)
• Native country: Australia
• Pest problem in California
– Discovered 1872
– Pest in Citrus orchards (1887)
• Control:
– Cyanide pesticide: failure
– parasite (Cryptochaetum
iceryae, Diptera)
– vedalia (Rodolia cardinalis,
Coleoptera)
• Achieved in 1 year
• Total cost: $1,500
2006
Prickly pear (Opuntia stricta)
• Native countries: Mexico,
South America
• Weed problem in Australia
– Ornamental (1839)
– Weed invasion: 1880-1925
243,000 km2 prickly thickets
• Control: moth Cactoblastis
cactorum from Argentina
– Achieved in 10 years (1940)
自然科学の英語-ENS-L7
Parasites and diseases
• Rabbits (Oryctolagus cuniculus) introduced in Australia (1859)
– 20 years later became a serious pest: ate pasture  desertification
• Control: mixoma virus (Leporipoxvirus) from S America (1950)
• Problems:
– escape in Europe (non-target area)
– resistance by natural selection (1965) BUT populations reduced < threshold
2006
Mixomatosis (Myers et al. 1954)
自然科学の英語-ENS-L7
Mixomatosis (Fenner and Myers 1978)
Problems of biological control
• Success rate 16% (Hall et al., 1980)
• Reasons:
– One species controls better than several
• Competition
loss of efficacy
– Introduced species may prey on non-target species
• Reduce efficacy
• Side-effects on ecosystems
To be effective
• Only if economic injury exists
• Specialist predators/parasites
– Generalist snail (Euglandina rosea) eliminated 60% of native snails
in Hawaii
– Indian mongoose (Herpestes auropunctatus) in Hawaii, Okinawa
and Pacific Islands
• After research on ecological effects: demography
2006
自然科学の英語-ENS-L7
Sterilization
• Irradiation of male insects (USDA, 1950s)
• Background
– X-rays caused sterility in male insects (1916)
– Dr Edward Knipling (1954) in screw-worm fly
(Cochliomyia hominivorax) - subtropical America
• livestock in Florida
• Forest insects in Canada
• Melon fly (Bactrocera cucurbitae) in Okinawa
(1972-1993) Koyama et al. 2004
• Tse-tse fly in Rhodesia
2006
自然科学の英語-ENS-L7
Immunocontraception
• Vaccine that reduces fertility
– glycoproteins (ZPG) inhibit egg fertilization
• Effective against wildlife populations
– Deer in New York
– Rabbits in Australia (invasive species)
2006
自然科学の英語-ENS-L7
Efficacy of immunocontraception
• Sterilization produces fewer offspring
• Surviving animals live longer - compensation
– High level of sterility is required (>80% females)
2006
自然科学の英語-ENS-L7
Pheromone traps
• Pheromones: chemical substances used by
animals (mainly insects) to communicate
– Moths and bark beetles
• Kinds
– aggregation
– sexual - released by females to attract males
• Advantages
• Shortcomings
– Species specific
– Sex specific pheromones most
effective (99%)
– Tiny amounts used as baits
– Work at long distance (30 kms)
– No possible ‘resistance’
2006
– Only adult insects
– Not applicable to all
insects pests
– Seasonal efficacy
(mating season)
自然科学の英語-ENS-L7
Chemical control: Pesticides
• Pesticides are a short-term solution, the last tool
to be used in IPM because:
– Contaminate the environment (water, soil, air) and
agricultural products (residues in vegetables, meat)
– Non selective: affect also non-target species
– Pest species eventually become resistant
– In some cases have produced more pest problems
• When can be used?
– Whenever there is economic injury and other
treatments are not effective
2006
自然科学の英語-ENS-L7
Kinds of pesticides
Insecticides
Insect pests
Neurotoxic
Herbicides
Weeds
Photosynthesis
Organochlorines
Triazines
Organophosphates
Phenylureas
Carbamates
Benzo-nitroamines
Pyrethroids
Neonicotinoids
Natural compounds
Germination
Nitroanilines
Chloroacetamides
Growth regulators
Growth inhibitors
Stomach poisons
Phenoxy-alkane
Repellents
2006
Defoliants
自然科学の英語-ENS-L7
Fungicides
Fungal diseases
Inhibitors
Respiration
Phthalates
Protein synthesis
Other synthesis
Triazoles
Cell division
Pesticides efficacy
Economic benefit = crop value - cost of control
• Pesticides  less
economic benefit
• Control cost
– Chemicals
– Spraying equipment
• tractor booms
• airplane or helicopter
– Personnel (applicators)
• Despite increasing use
after 30 years
– More pests
– More crop losses
2006
Crop losses in USA (Pimentel 1991, 1997)
自然科学の英語-ENS-L7
Insecticide problems for pest control
• Kill natural enemies
• Foster outbreaks of
insects which
become pests
– California red scale
(Aonidiella aurantii)
on lemon trees after
DDT
– Cottony-cushion
scale (Icerya
purchasi) on Citrus
after DDT
– insects in rice crops
(1965-1970)
2006
自然科学の英語-ENS-L7
(DeBach, 1974)
Paddy fields in Japan
Main
pest
species
YEAR 1950
Pest type
Technology
Aims
2006
Leptocorisa chinensis
Chilo supressalis
Sogatella furcifera
Nephotettix cincticeps
Nilaparvata
lugens
Laodelphas striatellus
Lissorhoptrus oryzophilus
Lagynotomus elongatus
Echinocnemus squameus
Cnaphalocrocis medinalis
Dicladispa armigera
Nephotettix cincticeps
Oulema oryzae
Sogatella furcifera
Scotinophara lurida
Nilaparvata lugens
Scirpophaga incertulas
Lissorhoptrus oryzophilus
Oxya spp
1960
1970
1980
Monophagous
Univoltine
1990
2000
Polyphagous
Multivoltine
Polyphagous
Multivoltine
Virus vectors
Green Revolution
Fertilizers
Irrigation
Pesticides
Mechanization
Nursery-tray treatment
Selective pesticides
Increase yield
Increase quality
自然科学の英語-ENS-L7
Low
density
Virus vectors
IPM
Education
Organic
Sustainability
After Kiritanai (1992)
Pesticide effects on ecosystems
• Direct effects due to toxicity
– Mortality: insecticides >fungicides>herbicides
– Sublethal (non-target organisms)
• Stress
parasites and diseases
• Reproduction: endocrine disruption (OC insecticides)
• Abnormal growth (malformation)
• Indirect effects - trophic web
– Food depletion
starvation
• Herbicides: phytoplankton
• Insecticides: zooplankton
2006
自然科学の英語-ENS-L7
death
migration
consumers starvation
algal blooms
Decline of birds of prey
1963 Ratcliffe: survey of Peregrine falcon in UK – 1/5 birds bred successfully
1964 Hickey et al.: surveys in US confirmed trend and raised alarm - raptors were
disappearing due to continuous reproductive failures
2006
自然科学の英語-ENS-L7
1966 Ames: reproductive failure of birds of prey correlated to shell-thinning
1967 Ratcliffe: eggshell thinning in certain raptors since 1947 (Nature 215:208)
1968 Hickey & Anderson: eggshell thinning in predators / fishing-eating birds
pesticides blamed
DDT in agriculture
(England)
2006
自然科学の英語-ENS-L7
1969 Laboratories confirmed the cause of eggshell thinning: organochlorines
Until 1974: debate on how DDT and organochlorines affected eggshell thinning
•
•
DDE caused shell thinning in birds of prey, but not in gallinaceous species (Cooke, 1975)
PCBs did not cause eggshell thinning (Peakall, 1993)
Cascade effect of
DDT & cyclodienes
Bioaccumulation
Calcium metabolism
Eggshell thinner
Embryo mortality
Decline reproductive rate
2006
自然科学の英語-ENS-L7
Local extinctions
Partridge (Perdix perdix) in many countries
• Causes of decline
–
–
–
–
Nest loss (26%)
chick mortality (29%  44%)
hunting (7%)
winter loss (38%)
Lack of food
Potts (1986)
2006
自然科学の英語-ENS-L7
Decline of birds due to pesticides
– Herbicides eliminate weeds  reduce insects and seeds
– Food shortage (insects, seeds) increase chick mortality
Species
Tree sparrow
Year decline started
Farmland (%)
Countrywide (%)
1978
-87
-76
1979
-85
-62
1978
-82
-78
Before 1969
-78
-78
1981
-75
-60
1975
-66
-52
1985
-46
-42
(Passer montanus)
Turtle dove
(Streptopelia turtur)
Grey partridge
(Perdix perdix)
Spotted flycatcher
(Muscicapa striata)
Skylark
(Alauda arvensis)
Song thrush
(Turdus philomelos)
Lapwing
(Vanellus vanellus)
2006
自然科学の英語-ENS-L7
Other ecosystems
Waterways
Crops
Forests
Urban
Transport routes
Air
Long-range transport
Volatilisation
Drift
Runoff
Groundwater
Rivers
2006
Leaching
自然科学の英語-ENS-L7
Drains
Rivers, lakes
Ocean
Pesticide losses
Transport route
Category
% applied rate
Spray drift
 Aerial application
 Ground-rig
 Manual (backspray)
5 - 10
0.1 – 3
?
Volatilization
 Very volatile
 Less volatile
50 - 90
1 - 10
Leaching*
 Water soluble
 Moderately soluble
40 - 90
10 - 25
Runoff
 Water soluble
 Insoluble
3-6
1-2
*Difficult to estimate due to sorption and slow movement
99% Pesticide losses  environmental contamination
(Pimentel et al., 1992)
2006
自然科学の英語-ENS-L7
Dissipation of pesticides
Half-life: the time required to reduce to half the amount of a substance
Volatilisation
Plants
Photolysis
Biodegradation
Absorption
UV Photolysis
Water
Soil
Photolysis
Hydrolysis
Biodegradation
Sedimentation
Biodegradation
Hydrolysis
Leaching
Residue
2006
自然科学の英語-ENS-L7
Residues in crop plants and products
deposit
diffusion
sequestration
metabolism
translocation
uptake
2006
自然科学の英語-ENS-L7
Ensuring food safety
• Cost of the Green Revolution
• Check residue levels in food
– National produce (market)
– Imports from other countries
(31 Quarantine Stations Japan)
• Analytical laboratories
– Huge cost for governments
• Reject food with residues >MRL
(Maximum Residue Limit)
Imported
(2001)
Tested
Residues found
Fresh vegetables
997,000
67,796 (6.8%)
729 (1.06%)
Frozen vegetables
717,000
21,501 (3%)
93 (0.43%)
32.5 million
2.4 million (7.4%)
Total food items
2006
自然科学の英語-ENS-L7
* Figures indicate tons
References
• Charles J. Krebs, 2001. Ecology 5th ed. / 応
用動物昆虫学 room B-226
• David Pimentel, 1991. Handbook of Pest
Management in Agriculture. CRC Press,
Florida, USA
• F. Moriarty, 1983. Ecotoxicology. Academic
Press / 応用動物昆虫学 room B-207
• Rachel Carson, 1962. Silent Spring.
Houghton Mifflin / 応用動物昆虫学 room B207
2006
自然科学の英語-ENS-L7