Study Guide for General Standards Pesticide Applicator Exam Illinois (2017)
Part 2 of 8 – Pesticide Application and Drift Reduction
There are three major types of applications:
Spot applications treat only a portion of the total area and are used to control pests that are grouped or clustered.
Band applications treat only a narrow strip over or alongside a row of desirable plants.
Broadcast applications treat the entire area or field.
Overlap is the portion of a spray pattern that applies over the adjoining pattern. Proper overlap is needed for uniform spraying.
Components of liquid application equipment.
Pump: moves liquid and creates pressure needed to spray the pesticide solution
Tank: holds pesticide solution
Agitation: portion of solution that is circulated back to the tank. Mixes pesticides to prevent them from settling out to bottom of tank
Strainers: mesh filters that prevent foreign objects in the spray solution from clogging or damaging the equipment
Pressure gauge: monitors pressure to ensure equipment is operating properly
Pressure and flow control valves: controls the flow of solution and prevents excess pressure
Nozzles: delivers the spray to the target – very important component
The type of nozzle and how it is used are important for controlling:
The amount of spray applied - flow rate of spray determined by orifice size
The uniformity of the spray – determined by nozzle pattern and overlap
Coverage of the target influenced by drop size
The potential for drift – influenced by droplet size
Droplet size influences coverage of target and spray drift
Small spectrum: provide better coverage, but more likely to drift
Nozzles produce a range of droplet sizes: droplet spectrum
Choose nozzles that provide good coverage for intended use and minimize drift
Sprayer maintenance and cleaning prevents damage and misapplications
Use clean water
Check and clean strainers daily
DO NOT use metal objects to clean nozzle
Flush new sprayer before using
Clean ALL sprayer components
Commercial cleaners recommended, especially with newer, more complex formulations
Consult label and use prescribed product specific cleaners (if applicable).
Drift is the physical movement of a pesticide through air at the time of application or soon thereafter, to any site other than that intended for application.
There are many problems associated with pesticide drift:
Particle drift is primarily influenced by droplet size, wind speed and wind direction
Equipment factors that influence drift:
Affect droplet size
Smaller droplets are more likely to drift
Orifice size determines droplet size
Some nozzle types designed to reduce the number of small droplets
Weather factors that influence drift
Application strategies for reducing drift
Control droplet size spectrum
Use nozzles which reduce small drift pone droplets
Reduce application pressure – watch rate controllers
Use drift reduction additives that increase droplet size
Lower boom height – be sure to maintain adequate overlap
Increase spray application rate – using higher spray application rates often means using nozzles with a larger orifice, which also increases spray droplet size
Do not spray when:
Wind speed is greater than 10 mph
Wind is blowing towards sensitive areas
Winds are shifting
During periods of calm or during an inversion
Leave an unsprayed buffer zone downwind – return to spray when wind is right
When available, use less volatile formulations
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