Drift mitigation glossary of terms

Application technique: The methods of application are broadly grouped under 'Field Sprayer' - including mechanically-drawn boom sprayers (e.g., tractor, truck or all-terrain vehicle mounted boom sprayers and self-propelled high-clearance sprayers); Chemigation Sprayer - all pressurized sprinkler irrigation delivery systems used for pesticide application (e.g., travelling guns, center pivots and overhead boom systems); Airblast Sprayer - includes all air-assisted fan sprayers used in orchard, vineyard and field crops (e.g., axial fan, cannon, and tower sprayers); and Aerial Sprayer - refers to either fixed-wing (airplane) or rotary-wing (helicopter) delivery systems.

Biological diversity: The variability among living organisms from all sources, including, without limiting the generality of the foregoing, terrestrial and marine and other aquatic ecosystems and the ecological complexes of which they form a part and includes the diversity within and between species and of ecosystems.

Boom height: The height of the boom above the top of the crop or bare ground (for pre-emergent applications) is required for the buffer zone calculator. Field sprayer boom heights of greater than 60 cm (24 inches) above the crop have a greater drift potential and are considered `high boom sprayers’ in the buffer zone calculator. Consult the nozzle manufacturer's guidance for the minimum effective boom height above your target.

Ditch: A depression or trench, either natural or constructed, that conveys drainage water away from a property area. Ditches are characterized by:

They often undergo mechanical or chemical maintenance and may or may not contain aquatic life.

Forest: A wooded area that’s larger than 500 hectares.

Grassland: An area with herbaceous plants dominated by grasses rather than large shrubs or tress. Grasslands may include:

Habitat: An ecological area that can support aquatic or terrestrial plant and wildlife species. Habitats may require protection from pesticide spray drift if they are identified as being at risk from adverse effects of pesticides. See definition for sensitive habitat.

Hedgerows: Lines or groups of trees, shrubs, perennial forbs, and grasses planted along field edges or other unused areas.

Land description: Identifying description that clearly indicates which section of property is being sprayed during the application event. This can include the:

Low-drift nozzle: Agricultural spray nozzles that produce larger spray droplets with fewer drift-prone fine droplets. Spray droplets are formed in a pressure-reducing chamber inside the nozzle. Low-drift nozzle designs include a variety of ways of creating low-pressure chambers inside the nozzle body. These include:

There are many considerations in choosing the correct type of low-drift nozzle for a given application. It’s recommended to consult an agronomist if in doubt.

Non-permanent water body: An area holding water for only part of the year. These bodies can be seasonal or temporary.

Nozzle: For selectable low-drift nozzles, information on manufacturer’s trade name and operating parameters is provided, which must be followed to achieve the benefits of drift-reduction. For example, the TeeJet Air Induction AI11002 nozzle must be used within the identified pressure range (2.0 – 3.0 bar / 29.0 – 43.5 psi) to achieve the allowed additional 75% reduction in buffer zones. For any nozzle with operating parameters not identified in the selectable list, users are required to select ‘Other’.

Nozzle flow rate: Nozzle flow rate (L/minute) used during application.

Permanent water body: An aquatic area holding water throughout the year. Examples of this kind of aquatic habitat include most:

Product label: The product label is approved as part of the registration process. It contains the conditions of registration that govern the use of the product. This is alongside the Pest Control Product Act and its regulations. In effect, the label is a legislative document. Use of a product in a manner that is inconsistent with the directions or limitations on the label is prohibited. Any control product offered for sale in Canada must bear the approved label.

Product registration number: The unique number assigned to each registered pest control product by the Pest Management Regulatory Agency (PMRA). The 4 or 5 digit number is found on the front page of the product label.

Relative humidity: The ratio of the amount of water vapour in the air at a specific temperature to the maximum amount that the air could hold at that temperature. It’s expressed as a percentage. Relative humidity (RH) at the time of application is required for aerial applications, as it affects spray drift potential. Pesticide carrier droplets (water) evaporate faster under low RH, increasing the distance they can travel before falling to the ground.

Seasonal water body: An area covered with water only part of the year. This area experiences flooding on a regular basis, depending on climatic conditions and patterns. An example is an aquatic area with water in the spring and summer but which dries out in the fall and winter.

Sensitive habitat: Any area containing or comprised of organisms that can be adversely affected by the pesticide product being applied. A sensitive habitat may be:

Shelterbelt: A barrier consisting of one to several rows of trees or shrubs on agricultural fields whose purpose is to:

Shrubland: An area covered by shrubs. It’s defined as having perennial woody plants, usually less than 10 m tall with branches near ground level but with no distinct trunk. Shrubs may be deciduous (such as hawthorn) or evergreen (such as holly).

Spray buffer zone: The distance between the point of direct pesticide application at the downwind end of the swath and the nearest downwind boundary of a sensitive habitat. Spray buffer zones are specified on product labels and are intended to mitigate adverse effects from non-target deposition of spray drift.

Spray drift: The wind-induced movement of spray particles (droplets) away from the spray swath during application. This definition doesn’t include vapour drift or other mechanisms of off-target deposition such as run-off.

Spray quality (ASAE): The ASAE Spray Quality Category system is based on the American Society of Agricultural Engineers S572.1 Standard (ANSI/ASAE S572.1 MAR2009).

The system classifies spray from nozzles in categories according to the volume mean diameter (VMD) of the droplets produced. A colour-coding system helps to identify the ASAE Spray Quality Category. The Buffer Zone Calculator allows for drift comparisons between ASAE Spray Quality Categories of:

Spray quality on label: The minimum ASAE Spray Quality Category shown on the Canadian product label, found under the ‘directions for use’ section.

Spray quality at application: The ASAE Spray Quality Category that the applicator wishes to use at the time of spraying. Required for use in the Buffer Zone Calculator for applications not using the recognized low-drift nozzles.

Streams: Watercourses that have source water flows from either upland headwaters or groundwater springs. They’re integral to the natural drainage of a watershed and may or may not contain aquatic life. Streams can be natural or channelized.

Temperature (°C): For aerial applications, the air temperature is required from the site of application or at the airfield (if located nearby to crop) at the time of application. The higher the air temperature, the faster the spray droplet will evaporate before reaching the ground. This increases its drift potential.

Temporary water body: An area covered with water only some of the time where the water-holding period is not regular or seasonal. An example is a lower part of a field flooded after a heavy rain or run-off.

Vapour drift: The evaporation and subsequent airborne movement of a pesticide from the sprayed material. Vapour drift can occur during application or at a later time from treated surfaces such as soil or plants. Products prone to vapour drift are identified on the product label along with any additional mitigation measures. For example, maximum air temperatures for application or setbacks from sensitive areas.

Vegetative filter strips: Permanently vegetated strips of land that sit between an agricultural field and downslope surface waters. Vegetative filter strips reduce the amount of pesticide entering surface waters from runoff by slowing runoff water and filtering out pesticides carried with the runoff. Certain pesticide labels will require a vegetative filter strip, other labels will recommend a vegetative filter strip as a best management practice. Read the label for specific instructions on vegetative filter strips.

Wetlands and riparian zones: Wetlands and riparian zones (the area between a defined aquatic and terrestrial habitat) possess characteristics of both aquatic and terrestrial habitats. These types of habitats include:

The primary characteristic of these areas is water covering at or near the surface of the soil for part or all of the year. Wetlands and riparian habitats may support both aquatic and terrestrial species.

Wind speed: For the Spray Buffer Zone Calculator, wind speed is entered in km/h. Wind speed should be measured at a height of at least 1.5 m above ground.

For airblast spraying, measure upwind of the orchard (from outside, not within, the planting). A wind vane onsite or a handheld anemometer will provide the most accurate readings. Prior to spraying, winds should be monitored over a 2 to 3 minute span. Record in particular the maximum sustained wind speed and average wind direction during that period.

Woodland (woodlot): A wooded area between 4 and 500 hectares. Examples of woodlots include:

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