What are Pests? 1 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Pests ● Any organism that bothers humans – Depends upon severity of interaction in terms of competition, health concerns or annoyance 2 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Pesticide Use by Sector 3 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1
Pesticide Use by Sector ● Public Health ● Agriculture ● Forestry ● The Home 4 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 5 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health I: Malaria ● Probably the most devastating insect transmitted disease in the world ● Typically tropical 6 BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment 2
Public Health I: Malaria ● Protozoan of Plasmodium genus ● Causes chills, fatigue, fever ● Infection of 300-500M/yr ● Death rate 1-10%, depending on treatment and sp. of Plasmodium 7 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 8 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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) 9 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 3
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 10 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health II: Yellow Fever ● Modern equivalent: West Nile Virus ● 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 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health III: Trypanosomiasis ● Sleeping sickness ● Known since 14th Century (Africa) ● Up to 50% mortality in some populations 12 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 4
Public Health III: Trypanosomiasis ● 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 13 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 14 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health IV: The Plague ● Rat disease, caused by bacteria ( Pasteurella pestis ) vectored by rat flea ( Xenopsylla cheopis ) ● Global disease control involves combining rodenticide and insecticides in ship hulls 15 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 5
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 16 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Public Health V: Typhus Fever ● 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 17 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 2 - Role of Pests in Agriculture ● Three main categories: – Insects – Diseases – Weeds ● Agriculture is largest user of pesticides by sector 18 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 6
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 800 2,00 11,600 28,000 38,000 50,000 ($ M US) 19 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Contribution of Pesticides to Cash Crops Actual losses Production without crop Losses prevented by protection 30.3% crop protection Weeds 13.2% Weeds 16.4% Animal 42.1% 27.6% pests 15.6% Animal pests 7.1% Diseases Diseases 13.3% 4.2% US$ 160 billion US$ 244 Attainable production - US$ billion 579 billion 20 BIO 4101: Pesticides and the Environment 15:32 BIO 4101: Pesticides and the Environment 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 21 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 7
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 on leaves, burning of leaves (secretion of toxins) ● May also be vectors of disease 22 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment Types of Damage Caused by Insects 23 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 know when to intervene ● Sometimes infestations occur and cause huge losses very quickly – e.g. locust swarms – e.g. armyworm “marching” across country 24 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 8
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 25 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 ) 26 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 27 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 9
A) Codling Moth ● 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 28 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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 29 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 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) 30 BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 10
Recommend
More recommend
