Chemical Controls
In IVM programs, herbicides are considered transition tools that enable
the manager to suppress weeds and replace them with desirable, competitive
vegetation. Thus, it is important to select the least-toxic, low-residual
herbicide that is effective against the target weed, and to apply them
in a judicious manner.
Use Herbicides
Properly
Use herbicides in accordance with their EPA-approved
label directions. Protective gear should always be worn when applying herbicides,
and applicators should be certified to apply pesticides. Maintain labels
and Material Safety Data Sheets (MSDS) of the pesticide products on file.
For the purpose of this bulletin, specific chemicals will not be discussed.
Chemical name brands and registrations change constantly and the concentrations
of chemicals allowed by each state varies. We believe the choice of chemicals
and concentration levels is site-specific and differs too widely to be
encompassed by any one bulletin. Check the label to make sure that the
product you choose is registered for the site you are treating. Consult
the Cooperative Extension Service, State Agricultural Experiment Stations,
or County Agriculture Commissioner for specific herbicide recommendations
and information on their use in particular localities.
Herbicide
Information Resources
Information on herbicides can be found in the Herbicide
Handbook, Federally Registered Pesticides, Farm Chemicals Handbook, Montana-Utah-Wyoming
Weed Management Handbook, The Pacific Northwest Weed Control Handbook,
and
The
Pesticide Manual (see
Pesticide Information Resources). These publications list specific
information on the chemical and physical properties of active ingredients
as well as recommendations and precautions for use.
Criteria
for Selecting an Herbicide
When choosing an herbicide, it is essential to avoid
or minimize negative impacts on non-target organisms, including the capability
of the soil to support desirable vegetation. Remember, the site (croplands,
rangelands, rights-of-way, etc.) you plan to treat must be listed on the
label. The following questions are useful when making a site-specific decision
about which herbicide to use.
Is the herbicide:
Application
Methods
In IVM programs, spot-treatment rather than broadcast
application over wide areas is the preferred herbicide application method.
Spot-treatment consists of various techniques for applying herbicides to
target weeds without impacting desirable vegetation or other non-target
organisms. Spot-treatment can reduce herbicide use, lower costs, lower
risks to non-target organisms including humans, and reduce drift. Broadcast
herbicide applications are recommended only when necessary (e.g., where
weed infestations are very dense and extensive, or when plant fuel must
be dry prior to controlled burns). In a weed containment program, herbicides
can be useful as a "border" spray to prevent infestations from moving into
non-infested areas.