6 Second Generation Pesticides Primarily synthetic organic compoundsOver 600 biologically-active compoundsBroad-spectrum agentsToxic to manyNarrow-spectrum agentsToxic to specific groupTarget species/Nontarget speciesSee Table 20-1 p. 514
7 The Case for Pesticides Save human livesIncrease supplies and lower cost of foodWork better and faster than alternativesHealth risks may be insignificant compared to benefitsNewer pesticides are becoming saferNew pesticides are used at lower rates
8 Characteristics of an Ideal Pesticide Kill only target pestsDo not harm other speciesBreak down quicklyDo not cause genetic resistanceAre more cost-effective than doing nothing
9 Individuals Matter: Rachel Carson Wrote Silent Spring which introduced the U.S. to the dangers of the pesticide DDT and related compounds to the environment.
10 The Case Against Pesticides Genetic resistanceCan kill nontarget and natural control speciesCan cause an increase in other pest speciesThe pesticide treadmillOnce started we must continue, often at higher and higher ratesPesticides do not stay putCan harm wildlifePotential human health threats
11 Superpests Superpests are resistant to pesticides. Superpests like the silver whitefly (left) challenge farmers as they cause > $200 million per year in U.S. crop losses.
12 Pesticide Protection Laws in the U.S. Government regulation has banned a number of harmful pesticides but some scientists call for strengthening pesticide laws.The Environmental Protection Agency (EPA), the Department of Agriculture (USDA), and the Food and Drug Administration (FDA) regulate the sales of pesticides under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).The EPA has only evaluated the health effects of 10% of the active ingredients of all pesticides.
13 Pesticide Regulation in the United States Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)Established 1947/Amended 1972EPA reviews evaluation of chemicalsSets tolerance levelsInadequate and poorly enforced
14 Pesticide Regulation in the United States Food Quality Protection Act (FQPA)Established in 1996New standards for pesticide tolerance based on no harm to human health
15 Other Ways to Control Pests Economic thresholdThe point at which economic losses caused by pest damage outweigh the cost of applying a pesticide.Adjusting cultivation practicesUse genetically-resistant plantsBiological pest control
16 Other Ways to Control Pests Biological pest control: Wasp parasitizing a gypsy moth caterpillar.
17 Other Ways to Control Pests Genetic engineering can be used to develop pest and disease resistant crop strains.Both tomato plants were exposed to destructive caterpillars. The genetically altered plant (right) shows little damage. Contains a gene from bacteria called the Bt gene.
18 Other Ways to Control Pests BiopesticidesInsect birth controlHormones and pheromonesIonizing radiation
19 Integrated Pest Management Ecological system approachReduce pest populations to economic thresholdField monitoring of pest populationsUse of biological agentsChemical pesticides are last resort