Chapter 3 (Herbicides and Weeds)

What is the difference between a contact and systemic herbicide?

-Contact: herbicides kill only the green portion of the plants where the herbicide directly contacts the weed. -Systemic: Move throughout the plant, whether foliar or root absorbed.

List the five precautions recommended for non-selective herbicide applications.

-Do not apply where the root systems of non-target trees or shrubbery may extend into treated areas. -Don't apply to frozen ground. The material will not be absorbed into the soil and will probably runoff to an undesirable area. -Use extreme caution in applying soil-residual herbicides on slopes. Heavy rain may cause the herbicide to runoff adn damage adjacent areas or pollute streams, rivers, or other bodies of water. -Use low pressure. High pressure applications often drift causing severe damage. -Choose non-corrosive materials when applying around machinery, fences, tanks or other metallic equipment. Be sure the herbicide is not detrimental to other materials stored in the area.

What are the five categories of selective herbicide applications?

-Foliage Spraying -Basal Spraying -Granular or Pellet -Spotgun or Exact Dosage -Cut Surface Herbicide

What are the three basic foliage spray treatments used in right-of-way management?

-Low Volume Ground Foliar -High Volume Ground Foliar -Aerial

What are the basic differences between low volume ground foliage and high volume ground foliage treatments?

-Low Volume: Backpack sprayers to boom sprayers are used. -High Volume: Trucks, tracked vehicle, or skidder are used with high pressure sprayer

How can plant leaf shape affect herbicidal action?

-Plant Characteristics -Climate -Characteristics of the herbicidal action

What climatic factors affect herbicidal action?

-Relative Humidity -Light -Precipitation -Wind -Temperatures

What is the difference between a selective and non-selective herbicide?

-Selective: kills specific weed pests and doesn't kill surrounding vegetation. -Non-selective: remove most or all vegetation.

What are "spotgun" applications?

A type of hand-held or backpack sprayer that deliver a pre-measured dose of concentrated herbicide to the base of target vegetation.

What is the difference between conventional basal spraying and low volume basal spraying?

Conventional: Thoroughly wets the entire lower portion of individual stems of the plants. Low Volume: A more concentrated herbicide mixture is used to conserve the amount of carrier applied per stem.

Do herbicides work more quickly in warmer or cooler temperatures?

Cooler Temps (Early morning/Evening)

What is the difference between a defoliant and a desiccant?

Defoliant: Causes leaves to drop from plants without killing the plants. Desiccant: Speeds up the drying of plant leaves, stems, or vines.

When are the best results from soil residual herbicides achieved?

Early spring before the weeds emerge or when they are small.

What is temperature inversion and how can it affect pesticide drift?

Ground air two to five degrees cooler than the air above it. Calm conditions early morning or evening.

Which is more susceptible to herbicides: seedlings or mature plants?

Seedlings

What are the most common mistakes made by applicators using cut surface herbicide treatments?

Spraying too much chemical to the cut surface, making improper frilling or girdling cuts, and applying too close to desirable vegetation.

If a plant's growing points are below the soil surface, which type of herbicide will provide better control: contact or systemic?

Systemic

If you want to completely kill existing vegetation and immediately replant with ornamental's, you should use a _____ herbicide that is short lived in the soil? A) Systemic B) Contact

Systemic

"Stump spraying" and "hack and squirt" are names for cut surface herbicide treatments. (T or F)?

True

Each pilot must be certified in the aerial standard in addition to right-of-way category to make aerial applications on right-of-way (T or F)?

True

In low volume basal spraying, stems are completely encircled and wet to rundown. (T or F)?

True

Non-selective chemicals must have moisture to enter plant root systems. (T or F)?

True

Root-absorbed herbicides are generally more effective when applied postemergence. (T or F)?

True

Temperature, moisture, soil-type and rate of application influence the persistence of a herbicide (T or F)?

True

How can you limit the potential for drift when using low volume ground foliage treatments?

Use appropriate adjuvants to lessen drift potential (Any substance added to the spray tank, separate from the pesticide formulation, that will improve the performance of the pesticide.)

What steps can you take to avoid drift and accidental spraying of non-target plants when using high volume ground foliage treatments?

Use appropriate adjuvants to lessen drift potential.