User manual

• Following mechanical cutting or clearing, allow stumps and
injured trees sufficient time to adequately resprout before
a
pplying VELPAR® L.
• Do not use VELPAR® L on frozen soils.
• Do not use DuPont™ VELPAR® L on lawns, driveways,
tennis courts, or other residential or recreational areas.
• Weed and brush control results from spring applications
depend on sufficient moisture to activate VELPAR® L.
• Do not cut treated vegetation for forage or hay nor graze
domestic animals on treated areas for 60 days following
application. For rates above 3 gallons per acre, do not cut
treated vegetation for forage or hay nor graze domestic
animals for 1 year.
SPRAY DRIFT MANAGEMENT
T
he interaction of many equipment- and weather-related factors
deter
mines the potential for spray drift. The applicator is
responsible for considering all these factors when making
application decisions. Avoiding spray drift is the responsibility
of the applicator.
IMPORTANCE OF DROPLET SIZE
The most effective way to reduce drift potential is to apply large
droplets (greater than 150–200 microns). The best drift
management strategy is to apply the largest droplets that provide
sufficient coverage and control. The presence of sensitive
species nearby, the environmental conditions, and pest pressure
may affect how an applicator balances drift control and
coverage. Applying larger droplets reduces drift potential, but
will not prevent drift if applications are made improperly or
under unfavorable environmental conditions! See the Wind,
Temperature and Humidity, and Temperature Inversions sections
below.
CONTROLLING DROPLET SIZE
GENERAL TECHNIQUES
• V
olume
- Use high f
lo
w rate nozzles to apply the highest
pr
actical spra
y v
olume. Nozzles with higher rated flows
produce larger droplets.
• Pr
essur
e
- Use the lo
w
er spr
a
y pressures recommended for
the nozzle
. Higher pr
essure reduces droplet size and does not
improve canopy penetration. When higher flow rates are
needed, use a higher-capacity nozzle instead of increasing
pressure.
•
Nozzle Type - Use a nozzle type that is designed for the
intended application. With most nozzle types, narrower spray
angles produce larger droplets. Consider using low-drift
nozzles.
CONTR
OLLING DR
OPLET SIZE - AIRCRAFT
• Number of Nozzles - Use the minimum number of nozzles
with the highest f
lo
w rate that provide uniform coverage.
•
Nozzle Orienta
tion
- Or
ienting nozzles so tha
t the spr
a
y is
emitted backwards, parallel to the airstream will produce
larger droplets than other orientations.
•
Nozzle Type - Solid stream nozzles (such as disc and core
with swirl plate removed) oriented straight back produce
larger droplets than other nozzle types.
BOOM LENGTH AND HEIGHT
• Boom Length (aircraft) - The boom length should not
exceed 3/4 of the wing length, using shorter booms
decreases drift potential. For helicopters use a boom length
a
nd position that prevents droplets from entering the rotor
v
ortices.
•
Boom Height (aircraft) - Application more than 10 feet
above the canopy increases the potential for spray drift.
• Boom Height (ground) - Setting the boom at the lowest
labeled height (if specified) which provides uniform
coverage reduces the exposure of droplets to evaporation
and wind. The boom should remain level with the crop and
have minimal bounce.
WIND
Drift potential increases at wind speeds of less than 3 mph
(due to variable direction and inversion potential) or more
than 10 mph. However, many factors, including droplet size
and equipment type determine drift potential at any given
wind speed. AVOID GUSTY OR WINDLESS
CONDITIONS.
Note: Local terrain can influence wind patterns. Every
applicator should be familiar with local wind patterns and
how they effect spray drift.
TEMPERATURE AND HUMIDITY
When making applications in hot and dry conditions, set up
equipment to produce larger droplets to reduce effects of
evaporation.
SURFACE TEMPERATURE INVERSIONS
Drift potential is high during a surface temperature inversion.
Surface inversions restrict vertical air mixing, which causes
small suspended droplets to remain close to the ground and
move laterally in a concentrated cloud. Surface inversions are
characterized by increasing temperature with altitude and are
common on nights with limited cloud cover and light to no
wind. They begin to form as the sun sets and often continue
into the morning. Their presence can be indicated by ground
f
og; however, if fog is not present, inversions can also be
identified by the movement of smoke from a ground source or
an air
craft smoke generator. Smoke that layers and moves
later
all
y in a concentr
ated cloud (under low wind conditions)
indicates a surface inversion, while smoke that moves upward
and rapidly dissipates indicates good vertical air mixing.
SHIELDED SPRAYERS
Shielding the boom or individual nozzles can reduce the
effects of wind. However, it is the responsibility of the
applicator to verify that the shields are preventing drift, and
not interfering with uniform deposition of the product.
SENSITIVE
AREAS
T
he pesticide should onl
y be a
pplied when the potential for
drift to adjacent sensitive areas (e.g., residential areas,
bodies of w
ater, known habitat for threatened or endangered
species,
non-tar
g
et cr
ops) is minimal (e
.g, when wind is
b
lo
wing a
w
a
y fr
om the sensiti
v
e ar
eas).
ADDITIONAL USE INFORMATION
23