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 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Pesticide Use by Sector Pesticide Use by Sector ● Public Health ● Agriculture ● Forestry ● The Home 3 4 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1 - Pesticides and Public Health Public Health I: Malaria ● Insects play major role in ● Probably the most devastating insect disease transmission transmitted disease in the world ● Mostly Diptera (>8 Families) ● Typically tropical ● Insects may be obligate hosts – e.g. Malaria in mosquitoes ● Insects may be facultative hosts – e.g. W Nile Virus in mosquitoes 5 6 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1
Chemical Control of Malaria Public Health I: Malaria ● Protozoan of ● Most significant Plasmodium genus intervention was with DDT ● Causes chills, fatigue, – e.g. Island of Sardinia fever • 1942 = 78,000 cases ● Infection of 300-500M/yr • 1951 = 9 cases after DDT ● Death rate 1-10%, – e.g. Ceylon depending on treatment • <1963 = 3M cases and sp. of Plasmodium • >1963 = 17 cases after DDT 7 8 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Banning of DDT Public Health II: Yellow Fever ● Effectiveness of DDT as pesticide is ● An arbovirus (arthropod borne unparalleled virus) – DDT on surface would persist and continue to ● Causes jaundice and infect flies on contact hemorrhagic illness ● After DDT was banned: ● YF not huge problem but still – Ceylon had 17 cases in 1963 endemic in some places • 1968 = 500,000 cases – WHO estimates 200,000 infections/ • 1970 = 2M cases yr with 30,000 deaths ● DDT still used in 3rd world although ● Outbreak in Ethiopia in 1959 alternatives exist (Deltamethrin) killed 15,000 people 9 10 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health III: Trypanosomiasis Public Health II: Yellow Fever ● Sleeping sickness ● Known since 14th Century (Africa) ● Modern equivalent: West Nile Virus ● Up to 50% mortality in some populations ● Although arbovirus lifecycle not tied to vector, treatment best when applied to vector ● Traditional approach: airsprays of chemical insecticide ● Nowadays, most common is larvicide in water ( B.t. ) 11 12 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 2
Public Health IV: Public Health III: Trypanosomiasis The Plague ● Caused by flagellated protozoan parasite of 2 spp. of ● AKA “The Scourge of Man” Trypanosomiasis ● Devastated entire cities and ● Trypanosoma ingested by TseTse some countries Fly ( Glossina sp.) ● 14th C in Central Europe 25M ● Parasite develops in fly and dead (1/4 of population) migrates to saliva glands ● London 1666 = 70,000 deaths ● Infects human at next blood meal ● India and China (1889-1918) = ● Flies hang-out under leaves, 10M deaths therefore airspray not very effective ● Last outbreak occurred <50yrs ● Best control a combination of ago vegetative clearing and pesticides 13 14 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health V: Typhus Fever Public Health IV: The Plague ● Caused by Ricksettia prowazeki and ● Rat disease, caused by bacteria transmitted by common body louse ( Pasteurella pestis ) vectored by rat flea – Pathogen picked up by louse during ( Xenopsylla cheopis ) bloodmeal, develops in gut and released ● Global disease control involves in feces combining rodenticide and insecticides in – Humans infected by breathing dust or ship hulls contact with wounds – In humid conditions, feces are infectious up to several months ● Treatment involves sanitation/hygiene and louse control with pesticides 15 16 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health V: Typhus Fever 2 - Role of Pests in Agriculture ● Associated with humans in crowded, un-sanitary conditions ● Frequent outbreaks in combat ● Three main categories: forces and prisons: “war fever” and “jail fever” – Insects ● WWII 1943: Naples, Italy under – Diseases siege – Weeds – Bomb shelters overcrowded and filthy – Epidemic of typhus was imminent ● Agriculture is largest user of pesticides – Arrival of Allied Forces with DDT was by sector 1st time typhus outbreak had ever been prevented 17 18 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 3
Contribution of Pesticides to Cash Crops Agricultural Use (%) by Sector Actual losses Production without crop Losses prevented by 1960 1970 1980 1990 2000 2010 protection 30.3% crop protection Weeds Herbicides 20 35 41 45 47 46 13.2% Weeds 16.4% Insecticides 37 37 35 28 27 28 Animal 27.6% 42.1% pests Fungicides 40 27 19 20 21 21 15.6% Animal pests 7.1% Diseases All Others 4 6 6 7 7 6 Diseases 13.3% 4.2% US$ 160 billion Market Value 800 2,00 11,600 28,000 38,000 50,000 US$ 244 Attainable production - US$ ($ M US) billion 579 billion 19 20 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Types of Damage Caused by Insects Insects as Agricultural Pests ● Depends largely on morphology of mouthparts ● Estimated that 75% of all animals are ● Chewing insects insects (mostly beetles) – Defoliators, borers, leaf miners, – Not surprising there are so many ecological root feeders interactions with insects ● Sucking insects – Insects are mostly beneficial, small number – Distort plant growth, stippling are pests on leaves, burning of leaves (secretion of toxins) ● May also be vectors of disease 21 22 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Insects as Agricultural Pests ● Insect pests usually cause incremental damage – Calculate EIL and ET to Types of Damage know when to intervene Caused by ● Sometimes infestations Insects occur and cause huge losses very quickly – e.g. locust swarms – e.g. armyworm “marching” across country 23 24 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 4
Effect of Insects on Food Production For example, Apples ( Malus spp.) ● In grain crops, insects may cause a decrease in yield but do not impact harvest ● Important crop in Ontario quality ● Plagued by codling moth (Cydia ● In fruit and vegetable crops, insects may pomonella ) , red-banded leafroller cause yield reduction and affect harvest ( Argyrotaenia velutinana ) and apple maggot quality due to aesthetic expectations ( Rhagoletis pomonella ) 25 26 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment A) Codling Moth A) Codling Moth ● 2 generations/yr. ● Gen 2: adults emerge, mate and lay eggs near ● Gen 1: adults emerge in spring, mate and fruit lay eggs in upper leaves ● Larvae attack fruit as they mature in late summer ● Larvae migrate to fruit and chew inside ● Therefore, 2 phases of damage ● Larvae eat inside fruit, many fruit fall to – Without intervention, losses can be 20-90% ground with insects in development ● Most damage not visible ● They leave apple, find shelter and pupate – Therefore, need to monitor – Pesticides only useful before larvae enter fruit 27 28 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment B) Red-banded Leafroller C) Apple Maggot ● Also 2 generations per year but occurs ● Most destructive pest of apples two weeks before codling moth ● May have 85% loss if not treated ● Early generation feeds mostly on leaves, ● Overwinters as pupae in soil later generation on fruit ● Adults emerge in early summer, mate ● Complicates treatment with pesticides and lay eggs just beneath skin of fruit ● Larvae burrows as they eat, leaving series of trails (railroad worm) 29 30 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 5
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