WEED CONTROL

What is a Weed??

What is a Weed?

• A weed is a plant growing where it is not wanted.• Ex. Red rice,

Giant Ragweed

How do weeds affect us??

• 2-Brainstorm….What are some affects of weeds on our everyday life?

6 Ways Weeds affect Humans

• Housing pest• Impurities in crops• Poisonous• Allergies• Costly• Aesthetic • Impure seed products

6 ways weeds affect humans

• Housing insects and disease.• Impurities in agriculture

products.–Ex.-red rice causes lower yields.

• Poisonous to livestock.• Allergic reactions-common

ragweed

Why do weeds cost $$?

• Competition for water and nutrients.• Competition reduces crop yields.• Expense of herbicides.• Contamination of seeds• Aesthetics

How do weeds compete with crops?

• Uses nutrients intended for crops.• Competes for growing space.• Interferes with harvest.• Crowds out crops and allows for crop

loss.

Review

• Define weed• The effects of competition on the crop

or yields• The effects of weeds on humans and

livestock• The aesthetic effects of weeds in home

yards and public areas• The economic effects on crop yields.

Identifying Weeds

• Weeds can be classified based upon their:– Lifecycle– Persistence– Leaf Structure

Weed Lifecycles

• Annuals- – Grow from seed and complete their life cycle in

one growing season

• Biennials-– Complete their life cycle in two growing seasons

• Perennials– Require two or more years to complete their

lifecycle

Persistence• Common Weeds: – These are more persistent and may or may not be

vigorous.– Cause serious problems to farmers because they reoccur

so often– Mostly annuals

• Noxious Weeds:– Most undesirable– Persistent growth makes them hard to control

• Leaf Structure:– Grasses– Broadleaf

Identifying Common Weeds

• Weed ID Project– You must collect 15 different common weeds– Label each weed, identifying their:• lifecycle• Persistence• leaf structure.

Review

• Major Weed Categories:– Lifecycle• Annual• Biennial• Perennial

– Persistence• Common• Noxious• Leaf structure

– Weed ID Project

Student Learning Objective

• Describe the methods of weed control.• Determine the use of chemicals to control

weeds.• Explain alternative methods of weed control.• Describe methods of weed management.

Methods for weed control1. Mechanical: hand pulling, hoeing, tractor cultivation, etc.

2. Biological: using parasites, predators, genetic engineering, etc

3. Cultural: cropping practices, host resistance, sanitation, varying planting dates

4. Chemical controls: use of herbicides.

•Herbicides are classified as either:

- Selective - kill only certain types of plants- Nonselective - kill all plants they come in contact with

- Herbicides are classified further according to the time they are applied.

- Pre-emergent- Post-emergent

What is the most common control practice? Why?

• Chemical control is still the most popular form.

What information must be listed on a pesticide label?

What information must be listed on a pesticide label?

• Brand, trade, or product name• Ingredient statement • Manufacturer • Registration number• Establishment number • Classification statement• Directions for use• Signal words and symbol• Precautionary statements

What information must be listed on a pesticide label?

• Statement of practical treatment• Environmental hazard statement• Re-entry statement• Storage and disposal statement

Mixing and Loading Pesticides

• Follow all instructions provided on the pesticide label.

• The most serious pesticide poisonings occur during mixing and loading.

Protective Clothing and Equipment• Refer to the pesticide label to determine the proper

protective clothing and equipment to use.

• Look for the signal words on the label.– Caution– Warning – Danger

Applying Pesticides• Some pesticides require extra personal protective

equipment.

• This is why it is important to follow all information provided on the label.

Alternative Methods of Weed Control• Hoeing and hand weeding• Use of mulch to smother weeds• Cultivating • Mowing• Burning

Disadvantages of Alternative Weed Control

• Labor intensive

• Unrealistic for large crops and pastures

Integrated Pest Management(IPM)

• Used to:

– Manage crop diseases

– Managing insect pests

– Managing weeds

What information must be listed on a pesticide label?

• Brand, trade, or product name• Ingredient statement • Manufacturer • Registration number• Establishment number • Classification statement• Directions for use• Signal words and symbol• Precautionary statements

What information must be listed on a pesticide label?

• Statement of practical treatment• Environmental hazard statement• Re-entry statement• Storage and disposal statement

Weeds Classed According to Lifecycle

• Annuals

• Biannuals

• Perennials

Weeds Classed According to Plant Type

• Grasses

• Broad Leaves

• Sedges

Weeds Classed According to Persistence

• Common Weeds

• Noxious Weeds