Protecting habitats from spray drift
Learn about why habitats need to be protected from spray drift and how to protect them. Also learn which habitats need to be buffered and when the buffer zones are not required.
On this page
- Why habitats need to be protected
- How to protect habitats from pesticide spray drift
- Sensitive habitats that require protection
- When spray buffer zones are not required
- For more information
Why habitats need to be protected
Protecting habitats in agricultural areas helps promote biological diversity. Having many different species of plants, animals, fungi and soil bacteria promotes healthy ecosystems. Healthy ecosystems in turn, provide valuable ecological services in agricultural areas.
Terrestrial habitats provide homes or shelter for birds, mammals and beneficial insects. Many of these are critical to integrated pest management programs and in providing pollination services for crops.
Shelterbelts and vegetated areas next to agricultural fields reduce soil erosion. They also help filter excess nutrients and pollutants from overland runoff before reaching waterways.
Aquatic habitats and wetlands support a large variety of wildlife. They provide flood control during rain events and water retention during dry periods.
Surface waters in agricultural areas can provide drinking water sources for:
- people
- wildlife
- livestock
Surface waters can also move downwards to groundwater sources.
How to protect habitats from pesticide spray drift
Be sure to follow pesticide label instructions for spray buffer zones. To protect wildlife habitat from harm due to pesticide spray drift, the PMRA may require spray buffer zones for certain products. A spray buffer zone is the downwind distance between the point of direct pesticide application, usually the end of the spray swath, and the nearest boundary of a sensitive habitat.
Figure 1 - Text Equivalent
This is a two-part diagram describing the position of spray buffer zones in an agricultural field. The diagrams show a tractor spraying a pesticide in a cropped area adjacent to terrestrial habitat at the edge of the field, with an aquatic habitat immediately beyond that. The wind is blowing from the field towards the sensitive habitats.
Diagram a) shows terrestrial spray buffer zones. It has vertical lines at the end of the tractor’s spray boom and at the upwind edge of the terrestrial habitat, indicating the spray buffer zone distance that would need to be observed.
Diagram b) shows aquatic spray buffer zones. It has vertical lines at the end of the tractor’s spray boom and at the upwind edge of the aquatic habitat, indicating the spray buffer zone distance that would need to be observed.
Spray buffer zones are found on pest control product labels in the ‘Directions for Use’ section, along with sprayer application instructions.
Spray buffer zones may be required for application methods such as:
- field sprayers, which include:
- boom sprayers for broadcast application to field crops
- over-the-row type boom sprayers for orchard or vineyard use
- airblast sprayers, including:
- towers
- canons
- recirculating sprayers
- air-assisted axial fans
- aerial sprayers, either fixed or rotary wing aircraft
- chemigation sprayers using overhead or drop nozzles
Spray buffer zones are not required for application methods such as:
- soil drench and soil incorporation applications
- shielded sprayers that extend to near ground level, such as:
- inter-row hooded sprayers
- low-clearance hooded or shielded sprayers
- spot treatment applications with hand-held or backpack sprayers
The PMRA’s spray buffer zones don’t take precedence over other spraying restrictions such as provincial no-spray setbacks. Spray buffer zones may be lower than other provincial or municipal spraying setbacks from aquatic or terrestrial areas. If this is the case, the larger setback must always be observed. This includes spray buffer zones:
- on the product label
- modified using the calculator
When multiple products are tank-mixed for an application, the:
- largest buffer zone must be observed
- spray quality can be no finer than the smallest droplet size category listed from each of the products
It’s not necessary to add buffer zone distances from individual products together.
Sensitive habitats that require protection
An environmental habitat is an ecological area that can support aquatic or terrestrial plant and wildlife species. Sensitive environmental habitats are defined by the Pest Management Regulatory Agency (PMRA). They are areas that contain plant and/or wildlife species that can be adversely affected by a pesticide.
A sensitive habitat requires protection from spray drift if it’s downwind from the treatment area.
A sensitive aquatic habitat is defined as an area adjacent to or within a spray area that consists of any form of:
- permanent water (present throughout the season)
- seasonal water (holds water only part of the season)
Sensitive aquatic habitats include:
- lakes
- rivers
- ponds
- creeks
- sloughs
- streams
- marshes
- wetlands
- reservoirs
- prairie potholes
- estuarine/marine waterbodies
A sensitive terrestrial habitat is defined as a vegetated area adjacent to or within a spray area that can include:
- woodlots
- grasslands
- shrublands
- hedgerows
- shelter belts
- riparian areas
- forested areas
Wetlands and riparian zones (the area between a distinctly aquatic and terrestrial habitat) possess characteristics of both aquatic and terrestrial habitats. They may support both aquatic and terrestrial species.
If a habitat is identified as being sensitive by the PMRA, it will be identified on the product label. However, some areas within, or adjacent to, treated crops are not considered to be sensitive environmental habitats and don’t need to be buffered.
When spray buffer zones are not required
Spray buffer zones are only required for particular uses specified under the ‘directions for use’ section of the product label.
Habitats that are upwind of the treated area don’t require labelled spray buffer zones. Spray buffer zones on the product label only need to be observed for sensitive habitats that are downwind of the area being sprayed.
Figure 2 - Text Equivalent
This diagram shows a tractor spraying a pesticide in a cropped area adjacent to terrestrial habitat at the edge of the field, with an aquatic habitat immediately beyond that. The wind is blowing from the sensitive habitats towards the field. The tractor is spraying right up to the vertical line at the downwind edge of the terrestrial habitat, indicating the spray buffer zone would not need to be observed.
Crops adjacent to treated areas are not considered to be sensitive terrestrial habitats and do not require spray buffer zones. However, the presence of terrestrial spray buffer zones on the label can be a good indicator of potential for damage to adjacent vegetation. Applicators are responsible for ensuring their spraying programs do not adversely affect neighbouring private properties.
Figure 3 - Text Equivalent
This diagram shows a tractor spraying a pesticide in a cropped area that is adjacent to an orchard of fruit trees. The tractor is spraying up to the edge of the target crop, which is identified by a dashed line, and is not required to observe any terrestrial spray buffer zone on the product label for the neighbouring crop.
Temporary bodies of water resulting from flooding of or drainage to low-lying areas are not considered sensitive aquatic habitats. Therefore, they don’t need to be buffered.
Seasonal water courses that are dry at the time of application don’t require aquatic spray buffer zones.
Agricultural drainage ditches constructed to remove excess water from fields are normally highly managed areas that don’t need to be buffered. They’re generally characterized by not having any headwaters and don’t form a part of the natural waterways that drain a watershed. These are areas that may undergo regular mechanical or chemical manipulation to maintain drainage flow.
Note that streams (channelized or natural) adjacent to agricultural areas are habitats and may need to be buffered. Streams are characterized by having a source for water flows (headwaters or spring-fed) and are integral to the natural drainage of a watershed.
Terrestrial buffer zones do not apply to vegetative filter strips unless there is a pre-existing sensitive terrestrial habitat within them. However, care must be taken when applying herbicides to adjacent fields.
For more information
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