Pesticides

Pests Any organism that: 1.competes with us for food 2.Invades lawns and gardens 3.Destroys wood in houses 4.Spreads disease 5.A nuisance

Pea Aphids

Gypsy Moth Caterpillar

Emerald Ash Borer

Pesticides Kill pests (undesirable orgs) Insecticides: kills insects Herbicides: kills weeds Fungicides: kills fungus Nematocides: kills worms Rodenticides: kills rodents RoundUp: Herbicide Raid: Insecticide D-Con: Rodenticide

Type: Chlorinated Hydrocarbons DDT Paul Muller discovered insecticide. Won Nobel Prize in Killed everything  ranoff into water (fish). Bioaccumulation: fat soluble.

DDT Effects Slow degradation..DDT interfered with Ca+ uptakes in birds  laid weak shells. Both Fish Eaters! Broken eggs led to decrease in pop. size!

DDT Side Notes Neurotoxin: opens insect Na+ channels  spasms/death. Resistant mutants

Human Effects Genotoxicity Carcinogen? Endocrine disruption Diabetes Miscarriages

Locally! Montrose Chemical on Normandy in Carson Dumped into sewers  emptied into White Point Palos Verdes White croaker fish! Daily breeze 2008: seals higher concentrations of DDT

Rachel Carson: Silent Spring 1960’s Showed effects of biomagnification and bioamplification of DDT. Showed public the effects of env. pollution.

Type: Organophosphates Malathion: Insecticide Used to combat Med. fruit fly in CA. Sprayed in San Bernardino. Treats head lice and scabies! Med Fly

Why Use Pesticides? 1) Saves lives. Ex: Malaria: a protozoan parasite infects RBCs. Passed on by mosquitoes. Kills 1-3 mill/yr. Found in humid areas. Malaria

Why Use Pesticides? 2) Increases food supplies 3) Increase money profits for farmers.

Case Study: Myxomatosis Virus introduced to rabbits in Australia. Pops went from mill. Now, only 50% effective. Intro’d another virus in ‘96

Why Use Pesticides? 4) Work faster and better than alternatives. You Can Then Eat the Dead Bugs!

Negatives 1) Pesticide Treadmill: All pests that are not killed reproduce  make resistance offpsring. Now, farmer has to use more pesticide or switch to another brand.

Negatives 2) Toxic to Non- target species Pesticides do not stay put (rain/wind runoff). Affects ALL orgs of ecosystem. Red- Tailed Hawk CA King Snake

Negatives 3) Human Sickness Acute (short-term) exposure: bleeding, vomiting. Chronic (long-term) exposure: nerve problems, brain damage, cancer, birth defects.

Pesticide Regulation Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), All pesticide use must be approved 1 st by the EPA. Pesticide makers must test for toxicity.

Integrated Pest Management Using a combo of pest control strategies: chemicals and alternatives. +

Alternatives to Pesticides 1) Introduce natural predators of bug: ex: ladybug and aphid 2) Put up smells that attract bugs away from crops (pheromones) 3) Spray boiling H 2 O Chrysanthemums

Alternatives 4) Genetically modify plants to be resistant to pests (GMO’s) Frost-Resistant Strawberries (from fish gene)? Broccoflower Tangelo: grapefruit and tangerine

Case Study: BT Insecticide Gene BT = protein found in natural soil bacteria, Bacillus thuringensis. Disrupts guts of insects Not toxic to humans or animals BT gene placed in corn to protect against corn borer.

BT gene placed in corn to protect against corn borer

Broccoflower

Tangelo = Tang. And Grapefruit

Advantages of GMO’s Less pesticides are used Higher nutritional content Possible vaccine delivery Less water used (on irrigation) Less inorganic fertilizers are used Enough food to feed the world!

Disadvantages of GMO’s Cross pollination with wild species reduces biodiversity Emergence of superbugs Fear of unknown allergens Centralized control of food production Poor farmers can’t afford GM patented seeds