1. Fertilizers, Pesticides & IPM

2. Fertilizers
Organic: Organic matter from plants and animals. Typically made from animal manure that has been allowed to decompose.
Inorganic: (synthetic) Produced commercially. Usually done by combusting natural gas, which allows nitrogen from the atmosphere to be fixed and captured in fertilizer.

3. Controlling Pests Pests are undesirable:
Competitors, parasites, and predators
In agriculture pests are mainly: Insects, nematodes, bacterial and viral diseases, weeds and vertebrates.
Loss can be large: Estimated at 1/3 of potential harvest and 1/10 of the harvested crop

4. Controlling Pests
Because a farm is maintained in a very early stage of ecological succession and enriched by fertilizers and water
It is a good place for crops
AND early-successional plants (weeds)
Weeds compete for all resources
Light, water, nutrients, and space to grow. Weed are also early successional plants as well!

5. Pesticides
Pesticide – a substance that kills/controls organisms that people consider pests
Insecticides targets insects & Herbicides target plants
1st generation: natural chemicals from plants, 2nd generation: synthetic, created specifically
Broad-spectrum pesticides: Designed to kill many different types of pests
Selective pesticides: Designed to kill a narrower range of organisms
Persistence: Length of time they remain deadly in the environment for years, magnified in food webs

6. The History of Pesticides
Pre- Industrial Revolution methods
Slash and burn agriculture
Planting aromatic herbs that repel insects
Modern science-based agriculture
Search for chemicals that would
reduce abundance of pests
The first, like arsenic,
were toxic to all life
Killed both pests and
beneficial organisms

7. Bioaccumulation – some pesticides are found to build up over time in the fatty tissues of predators
Example: DDT
When an organism containing the pesticide is eaten, the chemical is transferred to the consumer
Eventually leads to very high pesticide concentrations at high trophic levels

8. The History of Pesticides
Second stage began in the 1930
Petroleum based sprays and natural plant chemicals (e.g., nicotine)
Third stage was the development of artificial organic compounds
DDT, broad-spectrum
Aldrin and dieldrin used to control termites
Toxic to humans and has been found in breast milk

9. Resistance
Resistance – pest populations may evolve resistance to a pesticide over time. These are said to be resistant.
Pesticide treadmill – the cycle of pesticide development followed by pest resistance, followed by development of pesticide
Positive Feedback Loop

10. The History of Pesticides
Forth stage is a return to biological and ecological knowledge.
Biological control - the use of predators and parasites to control pests
The use of Bacillus thuringiensis (BT) is the most widely used BioInsecticide
Predatory insects such as ladybugs, or parasitic wasps
Proven safe and effective

11. Integrated Pest Management (IPM)
Fifth stage
IPM uses a variety of methods
Biological control
Chemical pesticides
Methods of planting crops (crop rotation, intercropping, planting pest resistant crop varieties, creating habitats for predators, limited use of pesticides)
Goal can be control, but never complete elimination of pests
Economically makes sense
Does less damage to ecosystem, soil, water and air

12. Integrated Pest Management
No-till or low-till agriculture another feature of IPM
Helps build levels of natural enemies of pests

13. Monitoring Pesticides in the Environment
World pesticide use exceeds 2.5 billion kg
US use exceeds 680 million kg
$32 billion worldwide, $11 billion in US
Once applied may decompose in place or be carried by wind and water
Breakdown products can also be toxic
Eventually fully decompose but can take a long time

14. What does the slide tell us about the overall usage in the US compared to the entire world?