unit 2 plants for food and fibre. pos fertilizers and soil nutrients chemical and biological...

Unit 2Plants for Food and Fibre

POS

- fertilizers and soil nutrients- chemical and biological controls K3-describe and interpret the consequences of using herbicides, pesticides and biological controls in agriculture and forestry K4-identify the effects of different practices on the sustainability of agriculture and environmental resources (e.g.,identify positive and negative effects of using chemical fertilizers and pesticides and of using organic farming practices)

Topic 6

Pests andPest Control

What is a pest?

Any unwanted organism that inhabits a particular area

It may be causing diseaseIt may be competing with the desired plant, (causing plants to die or produce less)hinders monoculture harvesting practices

Call the exterminator!

Types of pests

Other plants (weeds) and fungi:compete with crops for water, nutrients and space (sunlight)

Insects/Animals:eat crops/forests

Not a pest: pollinators (non-target organisms)

We see… a field full of food, they see… a field full of food.

We get upset with anything that tries to feed itself…if it impacts us

Weedshttp://images.google.com/imgres?imgurl=https://www.lakelawnandpond.com/images/

weedTypes.jpg&imgrefurl=https://www.lakelawnandpond.com/MiscWeedAlgaeIdent.aspx&h=343&w=590&sz=38&hl=en&start=25&um=1&tbnid=cWnKLrB_K2ghUM:&tbnh=78&tbnw=135&prev=/images%3Fq%3Dweed%26start%3D20%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26client%3Dsafari%26rls%3Den%26sa%3DN

Bark beetles-spread fungus:Dutch elm disease

Introduced species

Often, it is the species humans have contaminated an area with that take over in a particular environment. No natural predators

Ex. Dandelions, worms, zebra mussels, bark beetle almost totally wiped out elm trees)Dogs, horses, and rats are not native to North AmericaCats in Australia- rodentsKiller bees, diseases (SARS), tropical diseases

Examples/Precautions:

Customs at the borders prevents you from bringing plants, seeds, fruits, or animalsBoats travelling from one lake to another should be washed free of weeds, algae etc.

Chemical Control-Pesticides

icide = killerHerbicideInsecticideFungicide

Soil residuesPesticides build up in the soil, so that even after the growing season is over, the chemicals still remain in the soil, or might end up in water sources, such as rivers or ground water.

Biological Control

Using the species’ natural enemies to decrease the populationHow to get rid of mice? Get a cat.

Ex: cats, birds, insects, fungi, bacteria, and other microorganisms

Do bugs need drugs?

ImmunityContinually using the same pesticides will allow for resistance to build up, and we will need higher dosages of more toxic chemicals to poison pests

*remember DDT + mosquitoes

Non-target organisms

Certain pesticides will harm or even kill other species

such as the livestock that forage in the fieldChildren/pets playing on the lawnPollinatorsPlants you wanted to grow

Bioaccumulation

Build up of toxins throughout the food chain

Organic Food Production

A method of growing plants or raising animals without using chemical fertilizers or pesticides

Reducing the need for chemicals

Tilling, Crop rotations, manual weed removalPlanting genetically modified plants (selective breeding)Cutting weeds along the edges

Mass production vs. Organic

Advantages: less chemicals, more environmentally friendly

Disadvantages: food produced organically tends to be smaller and produce less due to lack of chemical fertilizer, which drives up the cost

Controlling pests…the natural way

Scarecrows

Hunting/Trapping

Manually weeding/tilling

The ol’ grab and pull technique… make sure you get the roots

Garden hoe

Garden claw

Roto-tiller

Horse/ox + plow

Tiller (Discer)

Assignments

Re-read pgs 165,167

Review Q's T 4-6

pg 162#1 (/4),2 (/3),5 (/5),6 (/3)

pg 174#2 (/3)

pg 175#2 (/6), 11 (/2), 12 (/3),13 (/4),14 (/3)

Projects due

Study sheet

Unit Exam