Pesticides and Pest Control Dr. Richard Clements Chattanooga State Technical Community College Dr. Richard Clements Chattanooga State Technical Community College

Key Concepts  Types and characteristics of pesticides  Pros and cons of using pesticides  Pesticide regulation in the US  Alternatives to chemical pesticides

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: Chemicals that kill undesirable organisms  Insecticides - insect killers  Herbicides - kill plants  Fungicides - kills fungus  Nematocides - kill nematodes (roundworms)  Fungicides - kills fungus  Nematocides - kill nematodes (roundworms)  Rodenticides - kill rodents TYPES:

Table 23-1 Page 520 Table 23-1 Major Types of Pesticides Type Insecticides Chlorinated hydrocarbons Organophosphates Carbamates Botanicals Microbotanicals Examples DDT, aldrin, dieldrin, toxaphene, lindane, chlordane, methoxychlor, mirex Malathion, parathion, diazinon, TEPP, DDVP,mevinphos Aldicarb, carbaryl (Sevin), propoxur, maneb, zineb Rotenone, pyrethrum, and camphor extracted from plants, synthetic pyrethroids (variations of pyrethrum), rotenoids (variations of rotenone), and neonicotinoids (variations of nicotine) Various bacteria, fungi, protozoa Persistence High (2–15 years) Low to moderate (1–2 weeks), but some can last several years Low (days to weeks) Biologically Magnified? Yes No

Table 23-1 Page 520 Table 23-1 Major Types of Pesticides Type Herbicides Contact chemicals Systemic chemicals Soil sterilants Fungicides Various chemicals Fumigants Various chemicals Examples Atrazine, simazine, paraquat 2,4-D, 2,4,5-T, Silvex, diuron, daminozide (Alar), alachlor (Lasso), glyphosate (Roundup) Tribulan, diphenamid, dalapon, butylate Captan, pentachlorophenol, zeneb, methyl bromide, carbon bisulfide Carbon tetrachloride, ethylene dibromide, methyl bromide Persistence Low (days to weeks) Mostly low (days to weeks) Low (days) Most low (days) Mostly high Biologically Magnified? No Yes (for most)

First Generation Pesticides  Primarily natural substances  Sulfur, lead, arsenic, mercury - used until 1920’s, but still persist in soil.  Sulfur, lead, arsenic, mercury - used until 1920’s, but still persist in soil.  Plant extracts: nicotine (from tobacco) pyrethrum (from crysanthemums), rotenone (from roots of tropical plants). All are degradable and are plants natural defense against insects.  Plant extracts: nicotine (from tobacco) pyrethrum (from crysanthemums), rotenone (from roots of tropical plants). All are degradable and are plants natural defense against insects.

Second Generation Pesticides - Began in 1939 with DDT  Primarily synthetic organic compounds  Broad-spectrum agents - toxic to many species  Broad-spectrum agents - toxic to many species  Target species - intended target  Nontarget species

Pesticide Use 75% are used in developed countries, but use in developing countries is increasing 25% of pesticide use in the US is for non agricultural uses: homes, lawns, gardens Average homeowner applies 10x more per hectare that US cropland Imported cut flowers are heavily dosed with insecticides. Since 1987 EPA labeled 100 chemicals “known or potential toxicological concern”

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

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

Water ppm Phytoplankton ppm Zooplankton ppm Rainbow smelt 1.04 ppm Lake trout 4.83 ppm Herring gull 124 ppm Herring gull eggs 124 ppm Biological magnification

The Case Against Pesticides  Genetic resistance  Can kill nontarget and natural control species. More a problem in diverse ecosystems where predator species are more likely to be able to control pest populations.  Can kill nontarget and natural control species. More a problem in diverse ecosystems where predator species are more likely to be able to control pest populations.  Can cause an increase in other pest species  The pesticide treadmill

The Case Against Pesticides  Pesticides do not stay put  Can harm wildlife  Potential human health threats – linked to: Childhood brain cancer Immune, nervous & endocrine system disorders  What can we do? What can we do?  Potential human health threats – linked to: Childhood brain cancer Immune, nervous & endocrine system disorders  What can we do? What can we do?

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA, 1947 & ‘72) 1. requires EPA approval for use by testing on animals 2. EPA sets tolerance levels - amount of pesticide residue that can legally remain on the crop when consumed. 2. EPA sets tolerance levels - amount of pesticide residue that can legally remain on the crop when consumed.

FIFRA cont’ 3. EPA banned chemicals: Most chlorinated hydrocarbons, several carbamates and organophosphates, herbicide Silvex. 4. requires EPA to reevaluate all approved active ingredients.

1993 study of pesticide safety by U.S. Academy of Sciences: Urged the government to: Collect better data on pesticide exposure Develop better tests to evaluate toxicity Consider cumulative exposure of all pesticides rather that basing regulation on exposure to single pesticides

Problems with FIFRA 1.Inadequately tested pesticides remain on the market for many years 2. Does not allow citizens to sue EPA 3. Allows EPA to lisence new chemicals w/o full health and safety data. How can we strengthen FIFRA? 1.Consider cumulative exposure to many pesticides, especially w/ children 2. Develop better test procedures

Food Quality Protection Act (FQPA) Requires consideration of exposure to more than one pesticide in foods Protects infants and children with tolerance levels 10x smaller Requires manufacturers to demonstrate safety of pesticide to children

Food Quality Protection Act (FQPA) How to strengthen: Help prevent contamination of groundwater by pesticides Improve safety for farmworkers Allow citizens to sue EPA

Primary goal of pest control Economic threshold - pt at which economic losses caused by pest damage outweigh the cost of applying a pesticide. Why do farmers not use this idea? 1. Careful monitoring of crops is difficult 2. “insurance spraying” (apply more just in case) 3. Cosmetic spraying - to make things look pretty Economic threshold - pt at which economic losses caused by pest damage outweigh the cost of applying a pesticide. Why do farmers not use this idea? 1. Careful monitoring of crops is difficult 2. “insurance spraying” (apply more just in case) 3. Cosmetic spraying - to make things look pretty Goal should NOT be complete eradication

Integrated Pest Management (IPM) 1.Frequent inspection of crops. 2.Crop & it’s pests evaluated in an Ecological system approach. 2. First use biological and ecological methods. Ex: Crop rotation, pest resistant crops, predatory insects. 3. Chemical pesticides only used when economic threshold reached. 1.Frequent inspection of crops. 2.Crop & it’s pests evaluated in an Ecological system approach. 2. First use biological and ecological methods. Ex: Crop rotation, pest resistant crops, predatory insects. 3. Chemical pesticides only used when economic threshold reached.  Goal - Reduce pest populations to manageable levels, not eradication.

How can IPM be promoted? Federally supported demonstration projects Sales tax on pesticides to fund IPM research and education train USDA field personnel and county farm agents to help local farmers Provide subsidies for farmers who use IPM

Effects of IPM

Other Ways to Control Pests  Adjusting cultivation practices: crop rotation, adjust planting times, plant trap crops and habitat for predators.  Adjusting cultivation practices: crop rotation, adjust planting times, plant trap crops and habitat for predators.  Use genetically-resistant plants: ex: Bt corn. Some disagree as to health and environmental safety.  Use genetically-resistant plants: ex: Bt corn. Some disagree as to health and environmental safety.  Biological pest control - ex: predator species, Bt spray, parasites.  Biological pest control - ex: predator species, Bt spray, parasites.

Other Ways to Control Pests  Use genetically-resistant plants  Biological pest control  Insect birth control  Hormones and pheromones  Ionizing radiation

Advantages of Biological control: 1.Minimizes genetic resistance 2.Focuses on target species 3.Nontoxic to non-target species 4.Saves $ (25$ for each 1$ invested)

Figure 23-7 Page 528 Lady bugs (Coccinellidae) Green lace (Chrysopidae)

Ways to reduce the threat of pesticides in the foods you eat: Buy less imported foods Scrub fruits and vegetables in soapy water Buy organic Grow your own organically