Presentation is loading. Please wait.

Presentation is loading. Please wait.

 What is a Pesticide?  Major Kinds of Pesticides  Benefits and Problems With Pesticides  Alternatives to Pesticides  Laws Controlling Pesticides.

Similar presentations

Presentation on theme: " What is a Pesticide?  Major Kinds of Pesticides  Benefits and Problems With Pesticides  Alternatives to Pesticides  Laws Controlling Pesticides."— Presentation transcript:


2  What is a Pesticide?  Major Kinds of Pesticides  Benefits and Problems With Pesticides  Alternatives to Pesticides  Laws Controlling Pesticides Use

3  Types:  Insecticides  Herbicides  Fungicides  Rodenticides  Regulated by the EPA

4  Broad spectrum pesticide  kills a variety of organisms, not just the targeted organisms  Doesn’t degrade = doesn’t decompose = persist and then accumulate in environment or organism.

5 o First generation pesticide Inorganic compounds Lead and mercury Botanicals- plant derived pesticides Nicotine  Second generation pesticide  Synthetic poison  Ex: DDT for mosquitoes used to control malaria




9  Chlorinated Hydrocarbons  Organic compound containing Chlorine Ex: DDT  Persist (do not degrade)  **Rachel Carson – “Silent Spring” = problems w/ pesticides  Organophosphates  Developed during WWII  HIGHLY toxic (bees/humans), but do not persist  Currently used in agriculture EX: Malathion, diazinon Neurotoxin, especially children  Carbamates  Not as toxic to mammals Ex: household sprays/traps RACHEL CARSON… ENVIRONMENTAL GODDESS

10  How are organophosphates different than chlorinated hydrocarbons?

11  Selective Herbicides  Kill only certain types of plants  Can be classified to the type of plant they kill Broad-leaf herbicides Ex: 2,4-D (2,4 dichlorophenoxyacetic acid) Ex: 2,4,5 –T (2,4,5, trichlorophenoxyacetic acid) Used with wheat, corn, rice (cereal grains = grasses) Grass herbicides  Nonselective – kill all vegetation

12  When would you use a broad-leaf herbicide? A grass herbicide

13  Sprayed to kill vegetation – Agent White, Blue, Orange  Ecological damage – decades to repair – destroyed mangroves (habitat for fish and coast protection from erosion), forests destroyed  Human effects  Agent Orange = (combination of broad leaf herbicides + dioxins)  birth defects, stillbirths, cancer  Dioxin in breastmilk – Vietnamese = 1800 ppt, US = 4 ppt

14  Benefit 1. : Disease control  Fleas, lice and mosquitoes carry disease Malaria Malaria- mosquito born 2.7 million people die each year Few drugs available, so focus is on killing mosquitoes DDT

15  Benefit 2. : Crop Protection  Pests eat and destroy 1/3 of world’s crops  Farmers save $3 to $5 for every $1 they invest in pesticides

16  Name the 2 reasons why pesticides are used?

17  Problem: Evolution of Genetic Resistance  Pest populations are evolving resistance to pesticides (right) Pesticide Treadmill  Cost of applying pesticide increases Because they must be applied more frequently or in larger doses  While their effectiveness decreases Because of increased genetic resistance in pests Resistance Management Refuge of untreated plants: allows mating of treated/untreated pests to delay resistance Remove surviving weeds after herbicide application

18  Problem: Kills non-target organisms  Spraying to kill insects can kill birds, fish, bees  Despite 33-fold increase in pesticides since the 1940s, crop loss has not really changed

19  Problem: Creation of New Pests  Pesticide kills predator or competitor of minor pest

20  Problem: Persistence, Bioaccumulation, and Biological Magnification  Bioaccumulation The buildup of a persistent pesticide or other toxic substance in an organisms body  Biological magnification Increased concentration of toxic chemicals in tissues of organisms at higher trophic levels, stored in fat Ex: Peregrine falcons (right), Bald Eagles


22  Problem: Mobility in the Environment  Do not stay where they are applied  harm non-target organisms.  Move through soil, water (run-off) and air

23  Effects of Pesticides  Handling food with pesticide residue Mild case: nausea, vomiting, headaches Severe case: damage to nervous system (neurotoxin!!!)

24  Long-term Effects of Pesticides:  Cancer- lymphoma and breast  Sterility  Miscarriage  Birth defects  Harms immune system

25  1984 Bhopal, India  Explosion at pesticide plant released toxic gas (cyanide)  Many died immediately  Others: problems to respiratory, reproductive, nervous systems

26  Using cultivation methods to control pests  Interplant mixtures of plants (alternating rows): polyculture !!  Crop rotation  Biological Control  Use of naturally occurring disease organisms, parasites or predators to control pests  Must take care that introduced agent does not attack unintended hosts CANE TOADS

27  Pheromones and Hormones  Can use pheromones to lure pests to traps  Reproductive Controls  Sterilizing some of the members  Sterile male technique: sterilize in lab and then release

28  IPM  Combination of pest control methods that keeps pest population low without economic loss  Controls pests, not eradicate  Cons: requires a lot of knowledge  Conventional pesticides are used sparingly when other methods fail HOW DOES IPM DIFFER FROM ORGANIC FARMING?

29  Farmers MONITOR pests and act when injury threshold is reached.  EX: Cotton – 1% of land; 50% of pesticide use in US. – WOW!! Organic cotton helps reduce pesticide use.

30  Rice Production in Indonesia  Predators of pests normally kept in check by pesticides IPM Introduced

31  Food, Drug, and Cosmetics Act (1938) –FDCA – determined pesticides need regulation!  Delaney Clause (1958) – no cancer causing substances; not cover raw foods.  Federal Insecticide, Fungicide, and Rodenticide Act (1947) – FIFRA – regulates what pesticides are sold based on safety.  Food Quality Protection Act (1996) – stricter guidelines on pesticide limits, covers raw food, reduce time to ban harmful pesticide.

32  Some US companies still make banned or seriously restricted pesticides  Product is exported  Importation of food tainted with banned pesticides from other countries  Global ban of persistent organic pollutants  Stockholm Convention on Persistent Organic Pollutants (2004) – requires countries to eliminate usage of the 12 most toxic chemicals.


Download ppt " What is a Pesticide?  Major Kinds of Pesticides  Benefits and Problems With Pesticides  Alternatives to Pesticides  Laws Controlling Pesticides."

Similar presentations

Ads by Google