Dave Jackson provides this blog as a source of information to the Pennsylvania forestry community.
Updates and news items on forestry related subjects are posted regularly.
Wednesday, February 8, 2017
Announcing New Backpack Sprayer Calibration Forest Science Fact Sheet
Penn State Forestry Extension has just released the fourth
in a series of Forest Science Fact Sheets. The latest in the series, entitled Backpack Sprayer Calibration Made Easy,
provides in-depth practical information on calibrating backpack sprayers for both
band applications and spot treatments. The fact sheet was written by Dave
Jackson, Penn State Forest Resources Educator, Art Gover, Penn State Wildland
Weed Management and Kimberly Bohn, Penn State Forest Resources Educator.
simply means determining the output of a sprayer so a known amount of spray
solution is applied to a given area. Applicators must know this if they wish to
apply an herbicide at a specific dosage, e.g., ounces or quarts per acre.
Failure to calibrate spray equipment can result in misapplication of
herbicides, repeat applications, damaged non-target plants, excess costs, as
well as environmental concerns.
This fact sheet presents a simplified process of calibrating
a backpack sprayer known as the “ounces to gallons” method. With this method,
the amount of spray, measured in ounces, converts directly to gallons per acre.
Band applications are fixed-width, fixed-speed
applications in which the applicator treats larger, continuous areas of
vegetation. In forestry applications, band treatments are commonly used for
spraying interfering plants such as hay-scented and New York fern. Band applications may also be used to treat weeds along
fence lines and trees planted in rows.
Spot treatments are used to treat discrete targets scattered
about a site, such as a single shrub or patches of continuous vegetation. This
is probably the most common use of a backpack sprayer. This type of treatment
is commonly used when controlling invasive shrubs such as multiflora rose, honeysuckle,
and autumn olive. Calibrating for these types of treatments allows the
applicator to estimate spray coverage so the mix will be effective without
over- or under-applying.
Taking the time to calibrate the application will
ensure the proper dose of herbicide is used. Although calibration represents an
“extra” step and time you feel you may not have, it is not. Applications cannot
be made correctly without first calibrating. Applicators who master calibration gain a valuable skill and take
control of the process rather than simply mimicking instruction that may be