1 Chemical Control of Malaria Public Health I: Malaria Protozoan - - PDF document

▶
1
SMART_READER_LITE
LIVE PREVIEW

1 Chemical Control of Malaria Public Health I: Malaria Protozoan - - PDF document

Aug 21, 2022 434 likes •576 views

What are Pests? Pests Any organism that bothers humans Depends upon severity of interaction in terms of competition, health concerns or annoyance 1 2 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

slide-1
SLIDE 1

1

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

1

What are Pests?

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

2

Pests

  • Any organism that bothers

humans

– Depends upon severity of interaction in terms of competition, health concerns

  • r annoyance

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

3

Pesticide Use by Sector

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

4

Pesticide Use by Sector

  • Public Health
  • Agriculture
  • Forestry
  • The Home

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

5

1 - Pesticides and Public Health

  • Insects play major role in

disease transmission

  • Mostly Diptera (>8 Families)
  • Insects may be obligate

hosts

– e.g. Malaria in mosquitoes

  • Insects may be facultative

hosts

– e.g. W Nile Virus in mosquitoes

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

15:32

6

Public Health I: Malaria

  • Probably the most devastating insect

transmitted disease in the world

  • Typically tropical
slide-2
SLIDE 2

2

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

7

  • Protozoan of

Plasmodium genus

  • Causes chills, fatigue,

fever

  • Infection of 300-500M/yr
  • Death rate 1-10%,

depending on treatment and sp. of Plasmodium

Public Health I: Malaria

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

8

Chemical Control of Malaria

  • Most significant

intervention was with DDT

– e.g. Island of Sardinia

  • 1942 = 78,000 cases
  • 1951 = 9 cases after DDT

– e.g. Ceylon

  • <1963 = 3M cases
  • >1963 = 17 cases after DDT

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

9

Banning of DDT

  • Effectiveness of DDT as pesticide is

unparalleled

– DDT on surface would persist and continue to infect flies on contact

  • After DDT was banned:

– Ceylon had 17 cases in 1963

  • 1968 = 500,000 cases
  • 1970 = 2M cases
  • DDT still used in 3rd world although

alternatives exist (Deltamethrin)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

10

Public Health II: Yellow Fever

  • An arbovirus (arthropod borne

virus)

  • Causes jaundice and

hemorrhagic illness

  • YF not huge problem but still

endemic in some places

– WHO estimates 200,000 infections/ yr with 30,000 deaths

  • Outbreak in Ethiopia in 1959

killed 15,000 people

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

11

  • Modern equivalent: West Nile Virus
  • Although arbovirus lifecycle not tied to

vector, treatment best when applied to vector

Public Health II: Yellow Fever

  • Traditional approach:

airsprays of chemical insecticide

  • Nowadays, most common is

larvicide in water (B.t.)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

12

Public Health III: Trypanosomiasis

  • Sleeping sickness
  • Known since 14th Century (Africa)
  • Up to 50% mortality in some populations
slide-3
SLIDE 3

3

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

13

  • Caused by flagellated protozoan

parasite of 2 spp. of Trypanosomiasis

  • Trypanosoma ingested by TseTse

Fly (Glossina sp.)

  • Parasite develops in fly and

migrates to saliva glands

  • Infects human at next blood meal
  • Flies hang-out under leaves,

therefore airspray not very effective

  • Best control a combination of

vegetative clearing and pesticides

Public Health III: Trypanosomiasis

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

14

Public Health IV: The Plague

  • AKA “The Scourge of Man”
  • Devastated entire cities and

some countries

  • 14th C in Central Europe 25M

dead (1/4 of population)

  • London 1666 = 70,000 deaths
  • India and China (1889-1918) =

10M deaths

  • Last outbreak occurred <50yrs

ago

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

15

  • Rat disease, caused by bacteria

(Pasteurella pestis) vectored by rat flea (Xenopsylla cheopis)

  • Global disease control involves

combining rodenticide and insecticides in ship hulls

Public Health IV: The Plague

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

16

Public Health V: Typhus Fever

  • Caused by Ricksettia prowazeki and

transmitted by common body louse

– Pathogen picked up by louse during bloodmeal, develops in gut and released in feces – Humans infected by breathing dust or contact with wounds – In humid conditions, feces are infectious up to several months

  • Treatment involves sanitation/hygiene

and louse control with pesticides

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

17

  • Associated with humans in

crowded, un-sanitary conditions

  • Frequent outbreaks in combat

forces and prisons: “war fever” and “jail fever”

  • WWII 1943: Naples, Italy under

siege

– Bomb shelters overcrowded and filthy – Epidemic of typhus was imminent – Arrival of Allied Forces with DDT was 1st time typhus outbreak had ever been prevented

Public Health V: Typhus Fever

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

18

2 - Role of Pests in Agriculture

  • Three main categories:

– Insects – Diseases – Weeds

  • Agriculture is largest user of pesticides

by sector

slide-4
SLIDE 4

4

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

Agricultural Use (%) by Sector

1960 1970 1980 1990 2000 2010 Herbicides 20 35 41 45 47 46 Insecticides 37 37 35 28 27 28 Fungicides 40 27 19 20 21 21 All Others 4 6 6 7 7 6

Market Value ($ M US) 800 2,00 11,600 28,000 38,000 50,000

19

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

Contribution of Pesticides to Cash Crops

15:32

20

Weeds 13.2% Diseases 13.3% Animal pests 15.6% Weeds 16.4%

Animal pests 7.1% Diseases 4.2%

Actual losses US$ 244 billion 42.1% 27.6% Production without crop protection 30.3% Attainable production - US$ 579 billion Losses prevented by crop protection US$ 160 billion

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

21

Insects as Agricultural Pests

  • Estimated that 75% of all animals are

insects (mostly beetles)

– Not surprising there are so many ecological interactions with insects – Insects are mostly beneficial, small number are pests

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

22

Types of Damage Caused by Insects

  • Depends largely on

morphology of mouthparts

  • Chewing insects

– Defoliators, borers, leaf miners, root feeders

  • Sucking insects

– Distort plant growth, stippling

  • n leaves, burning of leaves

(secretion of toxins)

  • May also be vectors of

disease

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

23

Types of Damage Caused by Insects

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

24

  • Insect pests usually cause

incremental damage

– Calculate EIL and ET to know when to intervene

  • Sometimes infestations
  • ccur and cause huge

losses very quickly

– e.g. locust swarms – e.g. armyworm “marching” across country

Insects as Agricultural Pests

slide-5
SLIDE 5

5

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

25

Effect of Insects on Food Production

  • In grain crops, insects may cause a

decrease in yield but do not impact harvest quality

  • In fruit and vegetable crops, insects may

cause yield reduction and affect harvest quality due to aesthetic expectations

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

26

For example, Apples (Malus spp.)

  • Important crop in Ontario
  • Plagued by codling moth (Cydia

pomonella), red-banded leafroller (Argyrotaenia velutinana) and apple maggot (Rhagoletis pomonella)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

27

A) Codling Moth

  • 2 generations/yr.
  • Gen 1: adults emerge in spring, mate and

lay eggs in upper leaves

  • Larvae migrate to fruit and chew inside
  • Larvae eat inside fruit, many fruit fall to

ground with insects in development

  • They leave apple, find shelter and pupate

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

28

  • Gen 2: adults emerge, mate and lay eggs near

fruit

  • Larvae attack fruit as they mature in late summer
  • Therefore, 2 phases of damage

– Without intervention, losses can be 20-90%

  • Most damage not visible

– Therefore, need to monitor – Pesticides only useful before larvae enter fruit

A) Codling Moth

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

29

B) Red-banded Leafroller

  • Also 2 generations per year but occurs

two weeks before codling moth

  • Early generation feeds mostly on leaves,

later generation on fruit

  • Complicates treatment with pesticides

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

30

C) Apple Maggot

  • Most destructive pest of apples
  • May have 85% loss if not treated
  • Overwinters as pupae in soil
  • Adults emerge in early summer, mate

and lay eggs just beneath skin of fruit

  • Larvae burrows as they eat, leaving

series of trails (railroad worm)

slide-6
SLIDE 6

6

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

31

For example, Cotton (Gossypium sp.)

  • Historically, largest user of pesticides among

agricultural crops

– 25% of world’s insecticides

  • Plagued by cotton boll weevil (Anthonomus

grandis)

– Introduced from Mexico in late 19th century – Adults feed on bolls, lay 200 eggs which hatch weeks later – Damage is extensive – Losses of $300M/yr

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

32

  • Historically, cotton farming has employed all

types of pesticides available

– 1920s: crop dusting of calcium arsenate – 1950s: DDT (bollworm quickly developed resistance) – Resistance also found for dieldrin, heptaclor, endrin and toxaphene

  • Nowadays, genetically modified cotton for

resistance may reduce pesticide use by as much as 80%

For example, Cotton (Gossypium sp.)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

33

Plant Disease in Agriculture

  • Over 100,000 plant diseases in NAm, 50,000 of

which are highly destructive

– 8000 spp. of fungi – 500 spp. of nematodes – 250 viruses – 160 spp. of bacteria

  • On a per crop basis:

– 115 diseases on tomato – 196 on potato – 77 on wheat – 112 on corn – 200 on apples

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

34

Plant Diseases

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

35

Plant Diseases

  • Pathological: caused by a

living microorganism or virus

  • Physiological: caused by

a continued deficiency of a nutrient

  • Losses not as dramatic as

from insects, not as

  • bvious as from weeds

– Often insidious, difficult to detect

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

36

Plant Diseases

  • Can attack plants from the very

beginning: planting of seeds

– Especially true for large seeded vegetables (e.g. peas, beans, corn, curcurbits) – Many seeds fail to germinate due to infection

  • Paradox: need early planting to

maximize growing season but cool, moist conditions promote development of disease

– Therefore, many seeds coated in fungicides

slide-7
SLIDE 7

7

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

37

Stages of Disease Development

  • 1) Inoculation

– Arrival of pathogen (e.g. egg, spore, larvae…)

  • 2) Incubation

– Development and growth of pathogen population

  • 3) Infection

– Pathogen enters plant and begins affecting it

  • Disease occurs when plant responds

– Wilting, cells die etc…

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

38

Conditions Required For Disease to Occur

  • 3 steps are required for diseases

– 1) susceptible host plant – 2) disease producing agent (pathogen) – 3) environment favourable to disease development

  • Eliminate any of these to prevent disease
  • ccurrence

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

39

How Disease is Controlled

  • 1) Exclusion

– Prevent disease from coming into area

  • 2) Eradication

– Eliminate pathogen from the area

  • 3) Protection

– Place protective barrier between pathogen and area of interest (usually chemical)

  • 4) Resistance

– Develop and use plant varieties that not susceptible to the disease

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

40

Weeds in Agriculture

  • Weed: any plant growing

in a place where it is unwanted

– May be desired elsewhere

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

41

Many Hundreds of Species of Weeds

  • In average hectare of

agricultural soil, may be several million weed seeds

  • If only 10% germinate, still

have hundreds of weed plants per sq. meter

– Competition for nutrients, light, water

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

42

Weedy Characteristics

  • Related to r-selected life history pattern

– High capacity for dispersal (colonization) – Potential for seed dormancy – Fast growth – Production of many offspring – Good competitors – Shade intolerant

slide-8
SLIDE 8

8

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

43

Crop Injury From Weeds

  • Reduced yields (competition)
  • Reduced quality (contamination)
  • Increased production costs

(management)

  • Poisonous or

irritating

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

44

Competition From Weeds

  • Wild mustard requires

2X as much nitrogen and 4X as much water as oats

  • Ragweed has 3X water

and nutrient requirements as corn

– Also causes allergies

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

45

Crop Losses to Weeds

  • Experimental plots:

– Corn in Illinois lost 81% – Corn in Minnesota lost 51% – Soybeans in Nebraska lost 45%

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

46

In Arid Areas (ex. Prairies)

  • Where water is limiting, crops sometimes

rotated on 3 year cycle

– 2 years production, 1 year fallow – Conserves soil moisture for crops – Creates need to control weeds in fallow year

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

47

Herbicide Use in Agriculture

  • Corn (most significant)
  • Other grain plants

– Wheat, barley, oats, rye

  • Brush control in pastures and rangelands

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

48

Most Common Herbicides

  • Accounted for approx. 95% (in decreasing order
  • f importance Internationally):

– Atrazine – Propachlor – Alachlor – 2,4-D – Butylate

Currently Glyphosate is #1 in USA

slide-9
SLIDE 9

9

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

49

Cosmetic Bans of Domestic Pesticides

  • 140 municipalities across

Canada Have some kind of ban in place

  • Entire Province of Quebec

since 2003

– Currently have lowest rates

  • f pesticide application in

Canada (50% decrease from 1994 levels)

  • Ontario followed suit in

2009

– Exceptions for public health and safety, agriculture, forestry and golf courses

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

50

Vertebrate Pests in Agriculture

  • Many species of birds and mammals are

pests but pesticides rarely used

– Trapping, shooting, noisemakers, scarecrows etc…

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

51

Rodents

  • Rats and mice are big pests of grain

storage

– Rodenticides used but must be tightly controlled around feed grain to avoid contamination – Most common is Warfarin (mostly used in home)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

52

Predators

  • Pests of livestock

ranchers

– Coyotes, wolves prey on sheep, calves, poultry

  • Sometimes pesticides have been used in

the past to poison predators (e.g. strychnine)

– Cause non-target problems because carrion also poisonous

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

53

Birds

  • Can be pests of fruit and grain crops

– Big losses from Robins and other songbirds in blueberry production – Big losses in corn from blackbirds (e.g. red- winged blkbrd, starlings, cowbirds)

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

54

Pests in Forestry

  • In North America, 1/3 of

area covered by forest

– Used for timber, recreation, aesthetics

  • In Canada, there are 3

hectares of forest for each hectare of cultivated land

slide-10
SLIDE 10

10

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

55

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

Forest Resources, Nat.Res. Canada

56

Millions of ha Harvested forest; 0.9 Managed forest; 144.6 Forest land; 309.8 Total forest and wooded land 401.9 Total land 909.4

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

57

  • Many forest pests, particularly insects

and disease

  • Losses may be due to wood destroyed or

from lost potential due to growth inhibition

Pests in Forestry

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

58

Temporal Dynamics

  • Forests are long-

lived, therefore often have cyclical

  • utbreaks of pest

populations

  • For example,
  • utbreaks of Spruce

Budworm follow several years of dry, mild spring weather

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

59

Major Insect Pests in Forestry

  • Gypsy Moth (Lymantria dispar)

– Introduced from Eurasia in 1869, hoping to create silk industry in Massachusetts – Silk industry failed but moth proliferated – Less than 20yrs later was defoliating New England deciduous trees

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

60

  • Spruce Budworm (Choristoneura spp.)
  • In Canada, have been 6 major outbreaks

since 1700

  • Synchrony between budworm and fir-

spruce-birch forests of E Canada and Maine

Major Insect Pests in Forestry

slide-11
SLIDE 11

11

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

61

Spruce Budworm Outbreaks

  • Outbreak in 1877 wiped out entire forest but

understory regenerated

  • In 1912, understory was a mature forest
  • After several dry seasons, fir forests completely

wiped out by 1919

  • Another outbreak occurred in 1949-1958 when

previous understory became mature forest

  • Post WWII attacks less severe due to chemical

intervention

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

62

Globalization and Exotic Pests

  • Asian long-horned beetle

(Anoplophora glabripennis)

  • Introduced from China to

Brooklyn in1996

  • Larva burrow in hard-wood

trees

– Maple, birch, willow etc.

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

63

Diseases in Forestry

  • For the most part, pesticides have not

played major role in regulating disease in forests

  • 2 exceptions

– White Pine Blister Rust – Dutch Elm Disease

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

64

White Pine Blister Rust

  • Cronartium ribicola (Fungi)
  • Requires 2 hosts to complete life-cycle
  • Spores produced on Ribes (currants)

released into wind and infect trees

  • Attacks 5-needled pines
  • High degree of mortality (100%)

in young pines

  • Pesticides used against Ribes

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

65

Dutch Elm Disease

  • 3 species of Ophiostoma

fungus

  • Introduced to NAm in

1930

  • Attacks almost all species
  • f Elm (Ulmus)
  • Fungus grows and

mycelium clogs vascular tissues, choking tree

– Slow, progressive death

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

66

  • Transmitted by 3 species of Bark

Beetles

  • Bark Beetles bore into dead or decaying

wood and lay eggs

  • Larvae burrow while developing
  • Emerging adults carry spores to healthy

trees for infection

  • Chemical pesticides are

used to control the beetle vectors

Dutch Elm Disease

slide-12
SLIDE 12

12

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

67

Herbicides in Forestry

  • Mostly restricted to roads, rights-of-way,

powerlines, railways

  • Also used to clear re-growth after clear-cut

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

68

Herbicides in Forestry

  • For weeding after clear cuts

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

69

Pesticides in the Home

  • Although agriculture is largest user, domestic

use is most frequent

  • Most important domestic pests:

cockroach, rats, termites

– Also: fleas, silverfish, mice, ants, clothes moths

  • Lawns may be attacked by grubs, beetles,

weevils, webworms, mice, moles, rabbits

– Ontario has passed a law banning the cosmetic use of pesticides (2009), following Quebec

BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment

Pesticide Market Breakdown (USA)

15:32

70 PROFESSIONAL MARKET

Insecticides

Herbicides Rodenticides Fungicides Other

CONSUMER MARKET

Insecticides Herbicides Rodenticides Fungicides

Total market = $1.8 Billion Total market = $1.8 Billion