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