Pest Control Chapter 12 APES 2010

What are pesticides?  Chemicals that kill pests Biocides- kill wide range of pests Biocides- kill wide range of pests Herbicides- kill plants Herbicides- kill plants Insecticides- kill insects Insecticides- kill insects Fungicides- kill fungi Fungicides- kill fungi

History of Pesticides  Every culture has used pesticides  Modern era of pesticides began in 1934 with development of DDT (Dichloro-Diphenyl- Trichloroethane)  Used in WWII to control parasites & tropical disease  Was cheap, stable, soluble in oil, easily spread over wide areas.  High toxicity for target organisms- kills 90% of target organisms in single application  It was the “magic bullet”- the answer to our prayers… or was it?

History of Pesticides  Indiscriminate & excessive use of pesticides has caused Damage to ecosystems Damage to ecosystems Harm to human health Harm to human health Creation of “superbugs” Creation of “superbugs”  ¾ of all pesticides are used in Most Developed Countries (MDC) but rates in LDC are on the rise by 7-8%.  DDT was banned in US in the 1970’s. We can now only use it in emergencies.  DDT is still used in many other countries- especially for control of mosquitoes. Children playing in DDT clouds at beach.

Types of Pesticides classified based on chemical structure 1. Inorganic Pesticides Arsenic, copper, lead, mercury Arsenic, copper, lead, mercury Highly toxic & indestructable Highly toxic & indestructable Neurotoxin- single dose can cause damage Neurotoxin- single dose can cause damage May be used on seeds to deter rodents May be used on seeds to deter rodents Arsenic poisoning from infected water sources in Bangladesh

Types of Pesticides 2. Natural organic pesticides Nicotine, rotenone Nicotine, rotenone Botanicals Botanicals From plants From plants

Types of Pesticides 3. Fumigants Carbon tetrachloride, carbon disulfide Carbon tetrachloride, carbon disulfide Become gases easily & penetrate easily Become gases easily & penetrate easily Used to sterilize soil or deter rodent infestation in stored grain Used to sterilize soil or deter rodent infestation in stored grain So dangerous, mostly banned So dangerous, mostly banned

Types of Pesticides 4. Chlorinated Hydrocarbons DDT, chlordane, aldrin, dieldrin, toxaphene, paradichlorobenzene (mothballs), DDT, chlordane, aldrin, dieldrin, toxaphene, paradichlorobenzene (mothballs), Block nerve signals Block nerve signals Fast & toxic, carcinogenic Fast & toxic, carcinogenic Biomagnify- stay in ecosystem Biomagnify- stay in ecosystem Toxaphene kills goldfish at 5 ppb- one of the highest toxicities for any compound Toxaphene kills goldfish at 5 ppb- one of the highest toxicities for any compound

Types of Pesticides 5. Organophosphates Parathion, malathion, DDVP, TEPP Parathion, malathion, DDVP, TEPP From nerve gas research From nerve gas research Extremely toxic to mammals, birds, & fish Extremely toxic to mammals, birds, & fish One drop of TEPP on skin is lethal One drop of TEPP on skin is lethal Quickly degrade so much less persistent in environment Quickly degrade so much less persistent in environment

Types of Pesticides 6. Carbamates Carbaryl, Mirex Carbaryl, Mirex Similar to organophosphates Similar to organophosphates Very toxic to bees Very toxic to bees If bees die, our crop yields will decrease drastically due to lack of pollinationIf bees die, our crop yields will decrease drastically due to lack of pollination

Types of Pesticides 7. Microbial agents or Biological controls- using live organisms or their toxins instead of pesticides using live organisms or their toxins instead of pesticides Bacillus thuingiensis (Bt)- kills beetles, caterpillars by destroying their digestive tract Bacillus thuingiensis (Bt)- kills beetles, caterpillars by destroying their digestive tract Parasitic wasps Parasitic wasps Ladybugs eat aphids Ladybugs eat aphids Viruses Viruses

Benefits of Pesticides  Reduce disease transmission by insect vectors (DDT sprayed to kill mosquitoes & prevent malaria, when stopped in 1964, malaria reappeared immediately) Which is more important? Protecting people or the environment? Which is more important? Protecting people or the environment? If you had to choose between contracting masses of worms that will make you go blind before the age of 30 or a small chance of cancer due to pesticide exposure it you live to 50 or 60, which would you choose? If you had to choose between contracting masses of worms that will make you go blind before the age of 30 or a small chance of cancer due to pesticide exposure it you live to 50 or 60, which would you choose?  Reduce crop losses by two-thirds. Farmers save $3-$5 for every $1 they spend on pesticides. Farmers save $3-$5 for every $1 they spend on pesticides. Lowers costs and increases crop quality Lowers costs and increases crop quality

Problems with Pesticides  Non-target organisms affected Potato aphid spraying killed migrating robins Potato aphid spraying killed migrating robins Insecticide spraying in CA killed salmon Insecticide spraying in CA killed salmon Honeybees disappearing Honeybees disappearing  Resistant individuals will develop due to natural selection  Pesticide is killing off natural predators that help control bad populations  Limited useful lifespan- can move far from original application spot (next slide)  Persistant organic pollutants (POP’s) are very long lasting and dangerous. Banned in most countries but persistent in soil & water  Affect Human Health (see slide 15) Acute- poisoning & illness Acute- poisoning & illness Chronic- cancer, birth defects, degenerative diseases Chronic- cancer, birth defects, degenerative diseases Pest resurgence leads to the use of higher doses or more toxic chemical use

The Grasshopper Effect  Many chemicals like chlorinated hydrocarbons evaporate from water & soil in warm areas & condense & precipitate in colder regions.  This happens over & over, “hopping” northward until it collects in polar regions.  Affecting top predators (polar bears, whales, & humans)  Some carcasses have to be treated as toxic waste they are so “infected” with pesticide.  Be familiar with “The Dirty Dozen”- Table on toxin review sheet

About Human Health…  Yaqui children in Mexico tested… Foothills children age 4-5 not exposed to much pesticide Foothills children age 4-5 not exposed to much pesticide Valley children age 4-5 repeatedly exposed Valley children age 4-5 repeatedly exposed

Alternatives to Pesticides  Crop rotation keeps pest population low. Using cover crops keeps weeds down Using cover crops keeps weeds down Provide habitat for natural predators (plant trees along edge of farm for birds which will eat bugs & provide windbreak which prevents erosion) Provide habitat for natural predators (plant trees along edge of farm for birds which will eat bugs & provide windbreak which prevents erosion)

Alternatives to Pesticides  Biological controls- natural predator Bacillus thuringiensis (Bt)- kills beetles & caterpillars Bacillus thuringiensis (Bt)- kills beetles & caterpillars Ladybugs, praying mantises, wasps Ladybugs, praying mantises, wasps Ducks & geese in fields will eat insects & weed seed. Ducks & geese in fields will eat insects & weed seed. Planting garlic or marigolds can deter pests. Planting garlic or marigolds can deter pests. Release of sterilized males (screwworms) Release of sterilized males (screwworms) Release of artificial hormones can disrupt life cycles (mosquitoes) Release of artificial hormones can disrupt life cycles (mosquitoes)

Alternatives to Pesticides  Integrated Pest Management (IPM)- use preventative measures to encourage growth & diversity with minimal use of chemical pesticides Vacuuming bugs off crops Vacuuming bugs off crops Trap crops- mature before rest of field to attract pests, then sprayed heavily, destroy trap crop to prevent spread to people or “real” crop. Trap crops- mature before rest of field to attract pests, then sprayed heavily, destroy trap crop to prevent spread to people or “real” crop. Educating farmers- In Indonesia farmers were spraying fields about 3x a week whether planthopper pest was present or not- made them pesticide resistant. By educating farmers about natural predators and using pesticides sparingly, helped increase crop yields & save $ on pesticide Educating farmers- In Indonesia farmers were spraying fields about 3x a week whether planthopper pest was present or not- made them pesticide resistant. By educating farmers about natural predators and using pesticides sparingly, helped increase crop yields & save $ on pesticide

Who regulates pesticide usage?  Environmental Protection Agency (EPA) Regulates sale & usage under Federal Insecticide, Fungicide, & Rodenticide Act (FIFRA) which mandates the “registration” of all pesticide products. Regulates sale & usage under Federal Insecticide, Fungicide, & Rodenticide Act (FIFRA) which mandates the “registration” of all pesticide products. Determines which pesticides are safe to use for humans & environment Determines which pesticides are safe to use for humans & environment Sets tolerance levels for residues that may remain in or on foods marked in U.S. This falls under the Federal Food, Drug, and Cosmetic Act (FFDCA). Sets tolerance levels for residues that may remain in or on foods marked in U.S. This falls under the Federal Food, Drug, and Cosmetic Act (FFDCA).  Department of Agriculture (USDA) & Food & Drug Administration (FDA) enforce pesticide use & tolerance limits set by EPA. Can seize & destroy food shipments that violate.

What can you do at home?  Plant grass that can compete with weeds. Don’t worry about the weeds- don’t we all love dandelions!  Repair screen doors to keep bugs out. Caulk windows, doors, etc to keep rodents, roaches, ants out  Clean up spills & remove garbage regularly; use flypaper, use borax for roaches  Kill aphids & other plant bugs by spraying with dilute detergent solution. Order ladybugs or praying mantis cocoons.  Use beer to drown slugs in gardens  Remove all sources of stagnant water to deter mosquitoes.  If you must use pesticides use them in small amounts & only when necessary; try not to use sprayers  Create mulch from your veggie scraps & kitchen waste & use as mulch to deter weeds.