Pest Control Pests and pollinators

The Ideal Pesticide The ideal pest-killing chemical has several qualities Kill only target pest Not coase genetic resistance in the target organism Disappear or break down into harmless chemicals after doing its job Be more cost-effective than doing nothing

Pests and Pollinators Pest Weed Pesticide Organism that damages valuable crops Weed Any plant that competes with crops Pesticide Poisons that target pest organisms

Types of Pesticides Insecticides Herbicides Fungicides insects plants

Pesticides $100 million kg (900 million lbs.) of pesticides are applied in the U.S. each year 75% agricultural land Usage increased in developing countries

Rachel Carson Wrote Silent Spring Introduces U.S. to dangers of pesticide DDT

Resistance Some individuals are genetically immune to pesticides They survive and pass these genes to their offspring Pesticides stop being effective Evolutionary arms race: chemicals increase chemical toxicity to compete with resistant pests

Biological control Biocontrol Uses pest’s natural predators to control the pest Reduces pest population without chemicals

Problems with Biocontrol Unpredictable effect of an introduced species “non-target” effect on the environment Removing biocontrol is harder than halting pesticide use

Integrated Pest Management IPM uses multiple techniques to suppress pests Biocontrol Chemicals Population monitoring Habitat alteration Crop rotation and transgenic crops Mechanical pest removal

Not all are pests Some insects are vital Pollination Pollinators 800 cultivated plant species rely on pollinators Pollination By wind or animals Flowers are evolutionary adapted to attract pollinators Pollinators Hummingbirds Bats insects

Conservation Native populations of pollinators have plummeted Honeybees pollinate more than 100 crops – 1/3 of the U.S. diet. In 2006, hives died off To conserve bees: Reduce or eliminate pesticide use Plant flowering plants