evr Pesticides learning objectives

The different chemical pesticide groups, what they are targeted to kill and specific examples of each

Pesticide: any chemical substance use to kill unwanted “pest” organisms

• 1/3 of U.S. crops are lost to pest each year (about 1/3 of cropsarelost when pesticides are not used

Insecticides: kills insects

• Nicotine(natural)

• Ex. Malathion, D.D.T.

Fungicides: kills fungi and molds

• ex. Methylmercury

Rodenticides: kills rodents

• ex. warfarin

Herbicides: kills weeds

• most used pesticide 60%

• ex. auxins

The difference between a hard and soft pesticide

Hard

• long half life

Soft

• short half life

The most commonly used pesticide

Herbicides: kills weeds

• Most used pesticide(60% of total)

• Ex. auxins

An example of a non-target pest affected by pesticide use

Bald Eagles

Pesticide half-life

The amount of time required for ½ of the chemical to break down

Which trophic levels are most affected by bioaccumulation/bioamplification

Bioaccumulation

• In all organisms/parts of the food chain

Bioamplification

• Near the top of the food chain

How species become tolerant to pesticides

Adaptations-Resistance to pesticides: the “natural selection” of individuals with a genetic tolerance to a pesticide

• second application of pesticide will be less effective

The concept of injury level/economic threshold level

When the cost of the pesticide application equals the profit from the harvest