Chapter 3: Integrated Vegetation Management

Allelopathy

A biological phenomenon by which a plant produces and releases one or more biochemicals that influence the growth, survival, and reproduction of other plants in the immediate vincinity

Aesthetic

a relative value of visual quality

Beneficials

plants or animals that assist unwittingly in the management of harmful plants and animals

Exotic species

living organisms growing in a region, country or continent, from which they did not oringinate

Integrated vegetative management (IVM)

System approach to vegetative management that allows you to combine all the appropriate tactics and methods including natural, biological, cultural, mechanical, and chemical, into a single unified vegetation management plan. Often used interchangeably with IPM in weed management

Nonselective control

a vegetation management program that kills all or most types of plants

Scouting

Regularly searching for, identifying, and assessing the number of pests and the damage they are causing in a particular location

Selective control

a vegetation management program that kills only target plants or groups of related plants

Threshold

a pest population level that requires action to prevent unacceptable injury or harm from the pest's actions

Introduction to IVM

Integrates pest control tactics that promote the survival of one group of desirable but compatible plants, while selectively controlling another group of undesirable plants ensuring the protection, stability, continuance, and safety of the common transport involved in the right-of-way.

- Based on ecological principles not agronomic principles

Identification (IVM)

- first step of weed control

- understand the life cycle to understand when it is most vulnerable to non chemical methods and to the herbicides in your chemical arsenal

- gather information how it was controlled in the past

Scouting (IVM)

Routine observation of your right-of-way and recording important information about your target pests gives you the information you need to develop and effective IVM plan.

- record mile by mile basis

- scouting form

- record name, height, soil conditions, and sensitive areas nearby

Monitoring (IVM)

Allows the assessment of plant growth along the right-of-way to determine the potential for undesirable plant population to reach a level that requires action

Site- specific requirements

Not all right-of-way treatments are the same. Spraying brush along a rural powerline drainage ditch is much more different from spraying brush or managing trees along powerlines in an urban neighborhood

Control strategies and methods

You will need to develop a weed control plan that is:

- effective, practical, economical, and environmentally sound

- combine several practices into a single one

- a single approach can fail over long term

- preventive, cultural, chemical, manual, mechanical, and biological

- keep records of everything

Prevention (IVM)

Prevention is simply stopping a problem before it starts

- take necessary steps to prevent seed production

- use weed-free seeds

- clean mowers and equipment when moving from weedy to weed free sites

- remove small patches before they infest large areas

Cultural Control

Aims to change the habitat in which weed thrive, controlling weeds indirectly.

- revegetation with native plants such as wildflowers or perennial grasses

encourage beneficial plants

Fertilization (Cultural Control IVM)

- encourage dense turf to develop which can discourage weeds

- fertilization is a long term cure or preventive measure and not a temporary control measure

Lime (Cultural Control IVM)

Can alter the pH of the soil, making some sites unsuitable for certain weed species. It often decrease the acidity of soil, which can inhibit the establishment and growth of some plants

Mulches (Cultural Control IVM)

Useful in established landscape plantings as they help slow weed growth around landscaped areas

Fire (Cultural Control IVM)

- fire promotes desired vegetation, particularly native plants

- control limited infestations of annual or biennial weeds

- only destroys the above ground parts of plants

Nurse crops (cultural Control IVM)

Annuals planted with a perennial crop to compete with weeds until the perennial is established

- the nurse crop is then harvested or removed

Competition (Cultural Control IVM)

The interaction between plants for important resources, including, nutrients, moisture, space, and light

Threshold of infestations (IVM)

point at which control measures are justified

Manual Control

Manual control is the use of hand-held tools to remove weeds

- work best in small areas (under or along guard rails)

- can be slective

Cons:

- labor intensive and expensive

- effective for short periods

- must be repeated often

Mechanical Control

Mechanical control use machines to cut and remove weeds. It is one of the most important and frequently used weed control option

- mowing is common and most effective on broadleaf weeds

- mow before viable seed head appears

target exposed growing points to kill the plant

cons:

- protected growing points are harder to kill

- can block the flow of water, cause erosion, and sparks from the machine can cause fires

Biological control

Biological control relies on living organisms, insects, animals, or plant pathogens to control undesired vegetation

pros:

- environmental friendly, cost effective, host specific, safe to handle/use

cons:

- slow to show results

- often lacks dramatic impact

- can be complex to use

- difficult to confine target plant pest species

Chemical Control

Chemical control using herbicides is often necessary on right-of-way. It can be used to complement other control measures. Consider what type of herbicide to use, best application technique, best seasons, type of equipment needed, and the mixing rate of additives

Advantages and Disadvantages of Chemical Control

pros

- less physical labor

- selective application

- may cost less compared to others

cons:

- can harm desirable plants if not handled properly

changing weather can make product less effective

- works quickly, but can have few long term effects

Combination of different control strategies

Can combine chemical with other control methods for example lets you are working on a road right-of-way

- clear weeds during highway construction (manual/mechanical)

- treat are with non selective herbicide (chemical)

- plant native vegetation (Cultural)