Application
Technology: Materials, Mixing and Mixtures
Excerpt from 2010-2011 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 requires adjustment, adjustments should be
made prior to the addition of spray material to 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.
1. dissolvable
packs
2. wettable powders
3. water dispersible granules and dry flowables
- Maintain agitation and fill spray tank to ¾ of total
spray volume. Then add:
4. water-based solutions
5. emulsifiable concentrates
6. 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 the Care and Use of Equipment section.
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.
Examples of colourants are listed below.
• Blazon:
blue, water soluble
• Bas-oil Red : red, oil soluble
• Dye Red
Foam
Colourants are available from agricultural chemical dealers.
Additional
Information
Video No. 39, Field Crop Sprayer Calibration,
No. 44, Nozzle Selection for Field Sprayers
Available from:
Independent Study, University of Guelph,
Guelph, Ontario Canada N1G 2W1.
Phone (519) 824-4120 ext. 3375.
www.horticulturecertificates.com/
OMAFRA
Factsheets
Reducing Pesticide Drift and Crop Damage, Order
No. 88-118
Pesticide Contamination of Farm Water Supplies, Order No. 00-099
Ways to Avoid Pesticide Spills, Order No. 96-025
Farm Pesticide Storage Facility,
Order No. 07-059
Field Sprayer Calibration, Order No. 88-129
Six Elements
of Effective Spraying in Orchards and Vineyards, Order No. 09-039
How Weather
Conditions Affect Spray Applications, Order No. 09-037W (web only)
Related Links
