Why are weeds - WCMS Agriscience

Pesky Weeds
Mr. Bailey
Weeds Around Kentucky!
What is a Weed?
• A weed is a plant that grows where it is
not wanted
• Examples
o Wheat growing in an oat field; the wheat
is considered a weed.
Why are weeds considered
• Weeds can be considered pests for many
different reasons. They can:
1. Harbor insects and disease
2. Compete with agricultural crops for
sunlight, water and nutrients
3. Grow to big sizes and can block
sunlight from other plants
Why are weeds considered
4. It can sometimes lower the quality of
the crop
5. If incorporated with grain it is not as
good for animals or humans
o Sometimes the seed can even be
6. Seed fast and spread quickly
Let’s identify some practices!
How are weeds controlled?
• People have many ways of controlling weeds
• Hoeing or pulling up weeds
• Animals have been used
• The best way is herbicides
What is a herbicide?
• A substance that is used to kill plants
 There are two kinds of herbicides:
1. Selective- these will kill only certain types of
2. Non-selective- these will kill all plants that it
comes in contact with
Herbicides used in the Agriculture
Exit Slip
1. Explain what a weed is in Agriculture.
2. Name three ways that weeds can be
controlled in Agriculture.
3. Name the two kinds of herbicides used
in the Agriculture Industry.

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