Application Technology: Materials,
Mixing and Mixtures
| Author: |
OMAFRA Staff
|
| Creation Date: |
25 November
2002
|
| Last Reviewed: |
20 June 2008
|
Excerpt from 2008 Publication 75, Guide to Weed Control, Order
this publication
 Table
of Contents
- Introduction
- Application Indicators
- Other topics in Application Technology
- Additional Information
- Related Links
Introduction
Dry herbicide formulations include granules, soluble powders and wettable
powders. Granules do not require prior mixing into a slurry. They are
ready to be mixed in water. Soluble powders can be dissolved in water.
Wettable powders will not dissolve but will form a suspension that requires
constant agitation.
Liquid herbicide formulations either mix in water to form a solution
or may be oil-based and form an emulsion that will require agitation.
Pesticide labels usually provide mixing directions for registered tank-mixes,
often describing the order of mixing. Whenever a label provides mixing
directions, they should be followed. Consult the package labels for information
on the compatibility of different herbicide products as certain formulations
may react when mixed together, resulting in materials with different properties
and activities than the original ones. If the pH or hardness of the water
needs to be adjusted, adjustments should be made prior to the addition
of other spray material in the tank.
When the label does not provide mixing instructions for a registered
tank-mix, pesticides should generally be mixed using the following procedure:
- Fill the spray tank with water to ½ of the total spray volume
required and start agitation. Add the different formulation types in
the order listed below, allowing time for complete mixing and dispersion
after adding each product.
- dissolvable packs
- wettable powders
- water dispersible granules and dry flowables
- Maintain agitation and fill spray tank to ¾ of total spray
volume. Then add:
- water-based solutions
- emulsifiable concentrates
- spray adjuvants
- Finish filling the spray tank to the required volume, maintain continuous
agitation during mixing and final filling, and throughout application.
Mixtures of different herbicides or mixtures of herbicides with pesticides
or foliar fertilizers should not be applied in a single application unless
registered for use in this way.
Unless specifically mentioned in this publication, or
on a herbicide label, the addition of a surfactant or a detergent to a
spray solution is not recommended.
Where water is known to have an excessive salt content, compatibility
of the water and the chemical at field strength should be tested first
on a small scale. See note on Agitation
in Care and Use of Equipment.
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Application Indicators
Colourants/Foam Markers for Pesticides Application
Colourants added to the pesticide solution help show where pesticides
have been applied. Foam marking systems help minimize overlap. Adding
a colourant to the basal sprays of herbicides on cut stumps of woody plants
helps assure thorough coverage without respraying. Water-soluble colourants
can also be useful in lawn spraying. Examples of colourants are listed
below.
- Blazon: blue, water soluble
- Basoil Red : red, oil soluble
- Dye Red Foam
Colourants are available through agricultural chemical dealers.
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Additional Information
Video No. 39, Field Crop Sprayer Calibration, No. 44,
Nozzle Selection for Field Sprayers
Available from:
Independent Study, University of Guelph,www.uoguelph.ca\istudy
Guelph, Ontario Canada N1G 2W1.
Phone (519) 824-4120 ext. 3375.
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OMAFRA Factsheets
Related Links
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For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
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