What is a Pesticide? Why Use Pesticides?

1. What is a Pesticide? Why Use Pesticides? Stephen J. Toth, Jr. Wayne G. Buhler Department of Entomology Department of Horticultural Science North Carolina State University North Carolina State University Photograph from USDA/ARS.

2. Webster’s Definitions of“Pest” and “Pesticide” Pest: “A plant or animal that is harmful or injurious to man.” Photograph from USDA/ARS. Pesticide: “A chemical substance used to kill pests, as rodents and insects.” Photograph from Mike Stringham.

3. Regulatory Definition of “Pesticide” “A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest, or intended for use as a plant regulator, defoliant, or desiccant.” Code of Federal Regulations, Title 40, Volume 16, Part 152 Photograph from USDA/ARS.

4. Common Types of Pesticides Algicides: control algae in lakes, pools and other sites Antifouling agents: kill or repel organisms on underwater surfaces Antimicrobials: kill microorganisms (bacteria, viruses) Attractants: attract pests (to lure a pest into a trap) Biocides: kill microorganisms Disinfectants: kill or inactivate disease-producing micro- organisms Fungicides: kill fungi (cause mildew, molds, etc.) Fumigants: gas or vapor to destroy pests in buildings/soil Herbicides: kill weeds and other unwanted plants

5. Common Types of Pesticides Insecticides: kill insects and other arthropods Miticides: kill mites that feed on plants and animals Microbial pesticides: microorganisms that kill, inhibit or out compete pest organisms Molluscicides: kill mollusks (snails and slugs) Nematicides: kill nematodes (plant-feeding roundworms) Ovicides: kill eggs of insects and mites Pheromones: biochemicals used to disrupt insect mating behavior Repellents: repel pests such as insects, birds and mammals Rodenticides: control rodents (rats and mice)

6. Additional Types of Pesticides Defoliants: cause leaves or other foliage to drop from a plant, usually to facilitate harvest Desiccants: promote drying of living plant tissue Insect Growth Regulators: disrupt life processes of insects (molting, pupa maturing to adults, etc.) Plant Growth Regulators: alter the growth, flowering or reproduction of plants (excluding fertilizers) White flower of cotton plant. Photograph from Jack S. Bacheler.

7. What is not considered a Pesticide? • Drugs used to control the diseases of humans or animals, which are regulated by the FDA • Fertilizers and plant nutrients used to promote plant health and survival • Biological control organisms except for certain microorganisms (i.e, ladybugs, wasps, etc.) • Low-risk substances such as cedar chips, garlic and mint oil are exempted from regulation by EPA • Pest control devices (i.e., mousetraps) are not pesticides, but subject to labeling requirements

8. What are Biopesticides? • Microbial pesticides: contain a microorganism (e.g., bacterium, fungus, virus, protozoan) as an active ingredient; example is Bacillus thuringiensis • Plant-pesticides: pesticide substances that plants produce from genetic material that has been added to the plant; example is Bollgard cotton which contains gene to produce Bacillus thuringiensis • Biochemical pesticides: naturally occurring substances that control pests by non-toxic means; examples include pheromones

9. Advantages of Biopesticides • Usually less harmful than conventional pesticides • Generally affect only target pests or closely related organisms (conventional pesticides have a more broad spectrum activity which is riskier to non-target organisms) • Often are effective in very small quantities and decompose quickly in environment • Can reduce dependence on the use of conventional pesticides (however, users must be knowledgeable of pest management and IPM)

10. Why Use Pesticides? “Humans have no divine right to their food supply; they must complete for it with weeds, plant diseases, insects, and other organisms.” (Grodner 1996) Johnsongrass. Photograph by Dale Monks. Bacterial spot on pepper fruit. Photograph by David Ritchie. Corn earworm infesting corn. Photograph by Jack Bacheler.

11. Numbers of Pest Species • About 10,000 insects classified as pests; these insects destroy our crops, attack livestock and transmit diseases • At least 600 species of plants are classified as weeds; these weeds compete with crops for sunlight, nutrients and water • Approximately 1,500 different fungi can cause plant diseases Boll weevil on cotton boll. Photograph by Jack Bacheler. Fruit rot of blueberries. Photograph by Bill Cline.

12. Pests Damage Fruit San Jose scale damage to apple. Photograph by Marvin Williams. Fruit rot of blueberries. Photograph by Bill Cline. Corn earworm on cotton. Photograph from USDA/ARS. Green mold (Pencillium) on orange. Photograph by Turner Sutton.

13. Pests Damage Foliage Leafminer damage. Photograph by Steve Bambara. Sooty mold caused by insect honeydew. Photograph by Steve Bambara. Tobacco mosiac virus. Photograph from NCSU Plant Pathology Dept. Japanese beetles feeding on blueberry foliage. Photograph by John Meyer.

14. Pests Damage Stems and Branches Terrapin scales on blueberry stems. Photographs from John Meyer. Nectria canker on apple tree caused by fungi. Photograph by Marvin Williams.

15. Pests Damage Roots Damage to peanut crop caused by sting nematodes. Photograph from NCSU Plant Pathology Department. Root knot nematode damage to the roots of okra plants. Photograph from NCSU Plant Disease and Insect Clinic. Black rot rot (CBR) of peanut. Photograph by Marvin Beute.

16. Pests DamageSeed and Seedlings Black cutworm damage to seedling. Photograph by James Baker. Damping-off caused by soil-borne fungi. Photograph from Turner Sutton. Western flower thrips damage to seedling. Photograph by James Baker.

17. Pests Attack Humans and Animals,Damage Structures Asian tiger mosquito. Photograph courtesy of P. Koehler, University of Florida. Norway rat. Photograph from Mike Stringham.

18. Economic Impacts of the Lossof Pesticides and Fertilizers • Weekly food bills of middle-income consumers would increase 12%; 44% increase for low-income consumers • The volume of grain and cotton exported from the U. S. would drop nearly 50% • Cultivated acreage in the U. S. would increase by 10%; erosion would rise • Crop production in the Southern U. S. would fall more than in other regions Pesticide application to trees. Photograph by Ken Hammond.

19. Pest Outbreaks of Historic Proportions • From 1845-1851, potato famine in Ireland resulted from fungal disease Phytophora infestans (late blight) • Stem rust destroyed 30% of wheat crop in U. S. in 1930 and 3 million tons of wheat in Western Canada in 1954 Late blight of potato. Photograph by Turner Sutton. Wheat harvest. Photograph by Tim McCabe.

20. Pest Outbreaks of Historic Proportions • Construction of the Panama Canal abandoned by French after 30,000 workers died of yellow fever (transmitted by mosquitoes) • In 1853, 12,000 persons died from yellow fever in New Orleans; 23 epidemics in the city from 1718-1860 Asian tiger mosquito. Photograph courtesy of P. Koehler, University of Florida.

21. Pest Outbreaks of Historic Proportions • 65 million persons have died of bubonic plague since the first recorded epidemic of the disease (caused by rat flea) Norway rat. Photograph from Mike Stringham.

22. References • U. S. EPA, Office of Pesticide Programs. What is a Pesticide? (http://www.epa.gov/pesticides/whatis.htm) • U. S. EPA, Office of Pesticide Programs. What is a Biopesticide? (http://www.epa.gov/biopesticides/ what_are_biopesticides.htm) • Grodner, M. L.. 1996. Why Use Pesticides? SERA-IEG 1 Pesticide Fact Sheets. (http://ipmwww.ncsu.edu/ safety/Southern_region/pestwhy.pdf)