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2006 自然科学の英語 -ENS-L7 Pest Control L7 English in Natural Science 自然科学の英語.

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Presentation on theme: "2006 自然科学の英語 -ENS-L7 Pest Control L7 English in Natural Science 自然科学の英語."— Presentation transcript:

1 2006 自然科学の英語 -ENS-L7 Pest Control L7 English in Natural Science 自然科学の英語

2 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

3 2006 自然科学の英語 -ENS-L7 Control of pest/weeds more crop yield nutrients light water crop harvest yield Market yield weeds diseases crop pests storage pests Disease12% Weeds13 Insects13* Storage20 Total48% * Rice 16.2% (Crammer, 1967) Crop losses

4 2006 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

5 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

6 2006 自然科学の英語 -ENS-L7 (After Van der Bosch et al. 1982) Biological control Scientific basis –Each pest has natural predators, parasites and competitors –Bring equilibrium predator-prey below the economic threshold of pest Long-term solutions Sustainable Increase of predatory populations

7 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 Prickly pear (Opuntia stricta) Native countries: Mexico, South America Weed problem in Australia –Ornamental (1839) –Weed invasion: ,000 km 2 prickly thickets Control: moth Cactoblastis cactorum from Argentina –Achieved in 10 years (1940)

8 2006 自然科学の英語 -ENS-L7 Parasites and diseases Mixomatosis (Myers et al. 1954) Mixomatosis (Fenner and Myers 1978) 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

9 2006 自然科学の英語 -ENS-L7 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

10 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 ( ) Koyama et al Tse-tse fly in Rhodesia

11 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)

12 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)

13 2006 自然科学の英語 -ENS-L7 Pheromone traps Advantages –Species specific –Sex specific pheromones most effective (99%) –Tiny amounts used as baits –Work at long distance (30 kms) –No possible ‘resistance’ Shortcomings –Only adult insects –Not applicable to all insects pests –Seasonal efficacy (mating season) Pheromones: chemical substances used by animals (mainly insects) to communicate –Moths and bark beetles Kinds –aggregation –sexual - released by females to attract males

14 2006 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

15 2006 自然科学の英語 -ENS-L7 Kinds of pesticides InsecticidesHerbicidesFungicides Insect pestsWeedsFungal diseases NeurotoxicPhotosynthesisInhibitors Organochlorines Triazines Respiration Organophosphates Phenylureas Phthalates Carbamates Benzo-nitroamines Protein synthesis Pyrethroids GerminationOther synthesis Neonicotinoids Nitroanilines Triazoles Natural compounds Chloroacetamides Cell division Growth regulatorsGrowth inhibitors Stomach poisons Phenoxy-alkane RepellentsDefoliants

16 2006 自然科学の英語 -ENS-L7 Crop losses in USA (Pimentel 1991, 1997) Pesticides efficacy 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 Economic benefit = crop value - cost of control

17 2006 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 ( ) (DeBach, 1974)

18 2006 自然科学の英語 -ENS-L7 Paddy fields in Japan Pest type Monophagous Univoltine Polyphagous Multivoltine Virus vectors Polyphagous Multivoltine Low density Virus vectors Green Revolution Fertilizers Irrigation Pesticides Technology Mechanization Nursery-tray treatment Selective pesticides IPM Education Organic Increase yield Aims Increase qualitySustainability After Kiritanai (1992) YEAR Lagynotomus elongatus Echinocnemus squameus Chilo supressalis Nephotettix cincticeps Laodelphas striatellus Dicladispa armigera Oulema oryzae Scotinophara lurida Scirpophaga incertulas Oxya spp Main pest species Cnaphalocrocis medinalis Nephotettix cincticeps Sogatella furcifera Nilaparvata lugens Lissorhoptrus oryzophilus Leptocorisa chinensis Sogatella furcifera Nilaparvata lugens Lissorhoptrus oryzophilus

19 2006 自然科学の英語 -ENS-L7 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 death migration Herbicides: phytoplankton consumers starvation Insecticides: zooplankton algal blooms

20 2006 自然科学の英語 -ENS-L 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 Decline of birds of prey

21 2006 自然科学の英語 -ENS-L 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)

22 2006 自然科学の英語 -ENS-L 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 Local extinctions

23 2006 自然科学の英語 -ENS-L7 Partridge (Perdix perdix) in many countries Potts (1986) Causes of decline –Nest loss (26%) –chick mortality (29%  44%) –hunting (7%) –winter loss (38%) Lack of food

24 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 SpeciesYear decline startedFarmland (%)Countrywide (%) Tree sparrow (Passer montanus) Turtle dove (Streptopelia turtur) Grey partridge (Perdix perdix) Spotted flycatcher (Muscicapa striata) Before Skylark (Alauda arvensis) Song thrush (Turdus philomelos) Lapwing (Vanellus vanellus)

25 2006 自然科学の英語 -ENS-L7 Transport routes Drift Other ecosystems Waterways Crops Forests Urban Volatilisation Air Long-range transport Leaching Groundwater Rivers Runoff Drains Rivers, lakes Ocean

26 2006 自然科学の英語 -ENS-L7 Pesticide losses Transport routeCategory% applied rate Spray drift  Aerial application  Ground-rig  Manual (backspray) – 3 ? Volatilization  Very volatile  Less volatile Leaching*  Water soluble  Moderately soluble Runoff  Water soluble  Insoluble % Pesticide losses  environmental contamination *Difficult to estimate due to sorption and slow movement (Pimentel et al., 1992)

27 2006 自然科学の英語 -ENS-L7 Dissipation of pesticides Volatilisation UV Photolysis Water Photolysis Hydrolysis Biodegradation Sedimentation Soil Biodegradation Hydrolysis Leaching Plants Photolysis Biodegradation Absorption Residue Half-life: the time required to reduce to half the amount of a substance

28 2006 自然科学の英語 -ENS-L7 Residues in crop plants and products deposit diffusion uptake metabolism translocation sequestration

29 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) TestedResidues found Fresh vegetables997,00067,796 (6.8%)729 (1.06%) Frozen vegetables717,00021,501 (3%)93 (0.43%) Total food items32.5 million2.4 million (7.4%) * Figures indicate tons

30 2006 自然科学の英語 -ENS-L7 References Charles J. Krebs, Ecology 5th ed. / 応 用動物昆虫学 room B-226 David Pimentel, Handbook of Pest Management in Agriculture. CRC Press, Florida, USA F. Moriarty, Ecotoxicology. Academic Press / 応用動物昆虫学 room B-207 Rachel Carson, Silent Spring. Houghton Mifflin / 応用動物昆虫学 room B- 207


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