Pesticides and Pest Control Brian Kaestner Saint Mary’s Hall Brian Kaestner Saint Mary’s Hall Thanks to Miller and Clements

Orange - groundwater contamination Pink - nitrate contamination Red - arsenic contamination

Pests  Compete with humans for food  Invade lawns and gardens  Destroy wood in houses  Spread disease  Are a nuisance  May be controlled by natural enemies

Pesticides: Types  Chemicals that kill undesirable organisms  Insecticides  Herbicides  Fungicides  Rodenticides See Table 20-1 p. 504

Grasshopper Gypsy moth caterpillar Fig. 20.2a, p. 505

Fig. 20.2b, p. 505 European red mite

Fig. 20.2c, p. 505 Boll weevil Pink bollworm ranges overlap

Fig. 20.3, p. 506

Fig , p. 514

Fig. 20.4, p Year Number of species Boll weevilGypsy moth cateripllar Insects and mites Weeds Plant diseases

First Generation Pesticides  Primarily natural substances  Sulfur, lead, arsenic, mercury  Plant extracts: nicotine, pyrethrum  Plant extracts are degradable Refer to Appendix 6 p. A8

Second Generation Pesticides  Primarily synthetic organic compounds  630 biologically-active compounds  Broad-spectrum agents  Narrow-spectrum agents  Target species  Nontarget species See Table 20-1 p. 504

Characteristics of an Ideal Pesticide  Kill only target pests  Harm no other psecies  Break down quickly  Not cause genetic resistance  Be more cost-effective than doing nothing

Fig , p. 514 MH JH MH JH MH Pupa Eggs Larva

The Case for Pesticides  Save human lives  Increase supplies and lower cost of food  Work better and faster than alternatives  Health risks may be insignificant compared to benefits  Newer pesticides are becoming safer  New pesticides are used at lower rates

The Case Against Pesticides  Genetic resistance  Can kill nontarget and natural control species  Can cause an increase in other pest species  The pesticide treadmill  Pesticides do not stay put  Can harm wildlife  Potential human health threats

Fig. 20.5, p. 507

Pesticide Regulation in the United States  Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)  Tolerance levels  EPA Evaluation of chemicals  Inadequate and poorly enforced  Food Quality Protection Act (FQPA)

Other Ways to Control Pests  Economic threshold  Adjusting cultivation practices  Use genetically-resistant plants  Biological pest control  Biopesticides  Insect birth control  Hormones and pheromones  Ionizing radiation

Integrated Pest Management  Ecological system approach  Reduce pest populations to economic threshold  Field monitoring of pest populations  Use of biological agents  Chemical pesticides are last resort

Effects of IPM Time Pest density Original pest population Introduction biological control Equilibrium position Equilibrium position Reduced pest population Economic threshold Fig. 20.7, p. 507