Pest Control

Outline Pests Pesticides Use and Types Benefits Problems Alternatives Reducing Exposure Regulating Use Organic Farming

PESTS AND PESTICIDES Biological Pests - Organisms that reduce the availability, quality, or value of resources useful to humans. Only about 100 species of organisms cause 90% of crop damage worldwide. Insects are most frequent pests. Make up three-fourths of all species. Generalists Compete effectively against specialized endemic species.

Pesticides Pesticide - Chemical that kills (repels) pests. Biocide - Kills wide range of organisms. Herbicide - Kills plants. Insecticide - Kills insects. Fungicide - Kills fungi. Acaricide - Kills mites, ticks, and spiders. Nematicide - Kills nematodes. Rodenticide - Kills rodents. Avicide - Kills birds.

Conventional Pesticide Use

Early Pest Controls Sumerians controlled insects with sulfur 5,000 years ago. Chinese describe mercury and arsenic to control pests 2,500 years ago. People have used organic compounds and biological controls for a long time. Romans burned fields and rotated crops to reduce crop disease.

Current Pesticide Use EPA estimates total pesticide use in the U.S. amounts to about 5.3 billion pounds annually. Roughly half is chlorine and hypochlorites used for water purification. Roughly 80% of all conventional pesticides applied in the U.S. are used in agriculture or food storage and shipping. Homes and gardens account for only about 8% of total pesticide use in the U.S..

Pesticide Types Inorganic Pesticides - Broad-spectrum, generally highly toxic, and essentially indestructible. (arsenic - copper) Generally neurotoxins Natural Organic Pesticides (Botanicals) - Generally plant extracts. (nicotine - phenols) Fumigants - Small molecules that gasify easily and penetrate materials rapidly. (carbon tetrachloride - ethylene dibromide)

Pesticide Types Chlorinated Hydrocarbons - Fast acting and highly toxic to sensitive organisms. (DDT - mothballs) Inhibit nerve membrane ion transport and block nerve signal transmission. Persistent - Tend to biomagnify. Organophosphates - Extremely toxic to mammals, birds and fish. (Malathion) Outgrowth of nerve-gas research. Inhibit neurotransmitter enzyme.

Pesticide Types Carbamates - Similar to organophosphates. (Sevin). - Extremely toxic to bees. Biological Controls Microbial agents Bacteria Parasitic wasps

PESTICIDE BENEFITS Disease Control Many insects serve as disease vectors. Malaria, Yellow Fever Crop Protection Using pesticides, pre-harvest losses to diseases and pests are at 30%, with post-harvest losses at an additional 20-30%. In general, farmers save an average of $3-$5 for every $1 spent on pesticides.

PESTICIDE PROBLEMS Non-Target Species Up to 90% of pesticides never reach intended target. Pesticide Resistance and Pest Resurgence Resistant members of a population survive pesticide treatment and produce more resistant offspring. Pest Resurgence Pesticide Treadmill

Creation of New Pests Broadcast spraying is also likely to kill beneficial predators. Under normal conditions many herbivorous pests are controlled by natural predators. With advent of chemical pest controls, farmers have tended to abandon traditional methods of pest / pathogen control. Mixed crops and rotation regimes.

Environmental Persistence and Mobility Because chlorinated hydrocarbons (DDT) are so persistent, they tend to show up far from the point of dispersal. Stored in fat bodies, and thus tend to bioaccumulate. High levels detected in upper levels of food chain. DDT banned from US for over twenty years, but high levels still detected in some areas.

Environmental Persistence and Mobility Many persistent organic pollutants were banned globally in 2001. Use was banned or restricted in developing countries for years, but between 1994 and 1996, the U.S. shipped more than 100,000 tons of DDT and POP’s annually. Many returned to U.S. in agricultural products and migrating wildlife.

Human Health Problems WHO estimates 25 million people suffer pesticide poisoning, and 20,000 die each year. At least two-thirds resulting from occupational hazards in developing countries. Long-term health effects difficult to conclusively document. PCB’s have been linked to learning deficiencies in children. Intake during mother’s pregnancy.

ALTERNATIVES TO PESTICIDE USE Behavioral Changes Crop Rotation Mechanical Cultivation Flooding Fields Habitat Diversification Growing in Pest-Free Zones Adjusting Planting Times Plant Mixed Polycultures

Alternatives to Pesticides Biological Controls Predatory / Herbivorous Insects Genetics and Bioengineering Hormones Sex Attractants

Integrated Pest Management Flexible, ecologically-based strategy that uses a combination of techniques applied at specific times aimed at specific pests. Tries to minimize use of chemical controls and avoids broad spectrum controls. Employs economic thresholds to determine the point at which potential economic damage justifies pest control expenditures.

REDUCING PESTICIDE EXPOSURE Less than 10% of active pesticide ingredients have been subjected to a full battery of chronic health-effect tests. Of the 321 pesticides screened, EPA reports 146 are probable human carcinogens. Since 1972, only 40 pesticides have been banned.

Regulating Pesticides Environmental Protection Agency (EPA), Food and Drug Administration (FDA) and Department of Agriculture (USDA) all share federal responsibility for regulating pesticides used in food production in the U.S.. EPA regulates sale and use, and sets tolerance levels. FDA and USDA enforce pesticide use and tolerance levels set by EPA.

Regulating Pesticides 1999, EPA banned use of methyl parathion on all fruit and many vegetables, and limited the quantity of azinphos methyl that can be used on foods common in children’s diets. Studies show children are more susceptible than adults to toxic pesticides because they are still developing and have less natural protection.

Is Organic the Answer ? Numerous studies have shown organic, sustainable agriculture is more eco-friendly and leaves soil healthier than intensive, chemical-based mono-culture cropping. Currently, less than 1% of all American farmland is devoted to organic growing, but market for such crops is growing.

Summary Pests Pesticides Use and Types Benefits Problems Alternatives Reducing Exposure Regulating Use Organic Farming