Pesticides Indicator

The Pesticides Indicator (official name: Indicator of the Risk of Water Contamination by Pesticides) evaluates the relative risk of water contamination by pesticides across agricultural areas in Canada. It can be used to assess pesticide inputs to cropland and the amount of pesticide transported to surface and ground water. This indicator has tracked pesticide risk associated with Canadian agricultural activities from 1981 to 2011.

What are Agri-Environmental Indicators?

Agri-Environmental Indicators (AEIs) are measures of key environmental conditions, risks, and changes resulting from agriculture and of the management practices that producers use to mitigate these risks. They help explain:

  • how the agriculture sector is performing,
  • why it is performing as it is,
  • whether that performance is satisfactory, and
  • how it is likely to evolve in the future.

Agriculture and Agri-Food Canada (AAFC) has been compiling and analyzing data and reporting on AEIs since 1993, but uses data from as far back as 1981. The Pesticides Indicator is one of several national indicators being tracked by AAFC.

Overall state and trend

Pesticide risk has been increasing on agricultural lands in Canada, although the majority of agricultural land is still considered to be at low or very low risk. From 1981 to 2011, the level of risk increased on 50% of agricultural land, primarily due to an increase in the area treated with pesticides and to unusually wet weather in the Maritimes and the Prairies in 2010.

Use the interactive map below to zoom in and explore different regions.  Note that in the Prairies, risk is considered to be low. While this region has the highest percentage of agricultural land treated with herbicides and fungicides, the dry Prairie climate means that there are fewer days with runoff and fewer pesticide applications per year. Most of the areas at very high risk, representing 7% of cropland, are located in Prince Edward Island, the Mixedwood Plains regions of Ontario and Quebec, the Red River region of Manitoba, the Parkland region of Alberta, and the Lower Fraser River Valley region of British Columbia.

In addition to exploring the 2011 values, click the play button to view changes over time. From 2006 to 2011 there has been a significant increase in risk, particularly in Ontario and Quebec, with isolated pockets of higher risk appearing in Alberta, Manitoba and Prince Edward Island.

Generally speaking, the increases in risk observed in between 2006 and 2011 were caused by an increase in the area treated with pesticides; in Eastern Canada and the Maritimes, this can be attributed to shifts from pasture and forage production to annual cropping systems, and in the Prairies to ongoing shifts from conventional tillage to reduced tillage and no-till systems, which require greater herbicide use for weed control. Between 2006 and 2011, there was a marked increase in the use of fungicides in the Prairies (from 3.7% to 7.5% of the land area) which can be attributed to wetter-than-usual weather in 2010, as well the shift to reduced tillage systems, both of which increase the risk of fungal diseases such as fusarium blight. Another factor that may have contributed to the increase in pesticide use per unit cropland in recent years is the expansion of land devoted to glyphosate-tolerant canola, soybeans and corn and the mass of glyphosate herbicide applied in these systems.

Figure 1: Relative risk of pesticide contamination of water on cropland under management practices in Canada in 2011

Legend: legend

Use the interactive map in Figure 2 to explore the change in pesticide risk between 1981 and 2011. It is apparent that the increase in risk is occurring across Canada.

Figure 2: Change in pesticide risk, 1981 to 2011

Legend: legend

Risk of Water Contamination by Pesticides performance index

The state and trend of the Pesticides Indicator can also be seen in the performance index below.

Figure 3: Risk of Water Contamination by Pesticides performance index
Description of this image follows.
Description - Figure 3
Year Index Value
1981 88
1986 86
1991 86
1996 88
2001 86
2006 85
2011 71

In 2011, the state of the environment, as it relates to pesticide risk resulting from farming activities in Canada, was in the "Good" category. The index illustrates a downward trend, representing increased risk to water quality. From 1981 to 2001, the overall risk remained stable, with about 90% of Canadian cropland in the low or very low risk category. By 2011, however, the level of risk had increased (as shown by a steep decline in the index values), with several areas moving into higher risk classes. From 1981 to 2011, the level of risk increased on 50% of agricultural land, primarily due to an increase in the area treated with pesticides. Much of this increase took place between 2006 and 2011, owing to a shift to cropping systems requiring greater use of pesticides, such as reduced tillage systems and, to a lesser extent, to wet weather in the Prairies and the Maritimes in 2010.

The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.

How performance indices are calculated

Specific trends

More land area is being treated with pesticides

The figure below shows the percentage of agricultural land area treated with pesticides for all Census years since 1981, by region, for the Prairies (Alberta, Saskatchewan and Manitoba) and the Maritimes (New Brunswick, Nova Scotia and Prince Edward Island), which have been grouped based on similarities of climate and agricultural activities, or by province (British Columbia, Ontario and Quebec). The Prairie region has the highest percentage of agricultural land treated with herbicides and fungicides, and Ontario, the Prairies and the Maritimes have the highest percentage of agricultural land treated with insecticides. Despite the application of pesticides to large areas across much of the Prairies, the risk of water contamination remains relatively low there, mainly because of the dry climate, which limits pesticide movement caused by runoff events.

Figure 4: Area treated with herbicides, insecticides and fungicides (% of agricultural SLC polygons)
Description of this image follows.
Description - Figure 4
Area treated by insecticides (%)
Year British Columbia Prairies Ontario Quebec Maritimes
Note: Maritimes analysis does not include Newfoundland and Labrador
1981 0.58 0.72 2.19 0.70 1.41
1986 0.64 2.65 2.28 0.61 1.53
1991 0.81 1.40 2.66 0.80 1.42
1996 1.07 3.68 3.28 1.20 3.49
2001 1.08 2.52 3.19 1.24 3.51
2006 0.93 2.56 4.39 1.31 2.80
2011 1.17 3.74 4.15 1.26 2.70
Area treated by fungicides (%)
Year British Columbia Prairies Ontario Quebec Maritimes
Note: Maritimes analysis does not include Newfoundland and Labrador
1981 0.50 0.98 1.15 0.52 1.46
1986 0.54 3.65 1.21 0.46 1.56
1991 0.54 1.89 1.38 0.60 1.45
1996 0.98 2.08 1.59 0.92 3.35
2001 0.94 3.31 1.69 1.01 3.37
2006 0.80 3.71 2.27 1.03 2.91
2011 0.87 7.54 3.43 1.08 2.97
Area treated by herbicides (%)
Year British Columbia Prairies Ontario Quebec Maritimes
Note: Maritimes analysis does not include Newfoundland and Labrador
1981 4.34 19.62 16.61 5.64 5.82
1986 5.10 30.88 17.68 7.65 6.49
1991 4.47 29.46 15.73 8.14 5.25
1996 5.60 32.41 17.49 9.41 6.64
2001 6.02 35.98 19.36 12.37 6.85
2006 4.44 32.96 18.82 11.71 5.85
2011 5.14 35.09 20.76 12.78 6.42

* The large increase in area treated by insecticides and fungicides in the Maritimes between 1991 and 1996 is likely an artifact from different data sources between these years.

Reasons for increasing pesticide use

The primary reason for increase in pesticide use in Canada over the past 30 years is due to the shift away from livestock – cattle in particular – towards food crops, which require more inputs. According to Health Canada's Pest Management Regulatory Agency (PMRA), pesticide sales (based on weight of active ingredients) increased by 13.9% between 2008 and 2010. Furthermore, the increased use of reduced tillage and no-till on the Prairies, while greatly benefitting the health of our soils, has resulted in an increased reliance on pesticides, leading to an increased risk to water quality.

Why this indicator matters

Pesticides help agricultural producers reduce losses caused by weeds, insects and plant diseases, enabling a greater diversity of crops to be grown on existing farmland. While most pesticides are formulated to target a specific pest organism, the active ingredients found in some products may also cause unintentional harm to non-target species, which can become exposed when pesticides move from on-farm application sites into the surrounding environment and contaminate surface and ground water. Pesticide residues have been detected in surface and ground water in monitoring studies conducted in various regions of Canada, raising concerns for potential adverse effects on wildlife as well as on drinking water quality.

Agriculture has the potential to mitigate risk from pesticides by implementing beneficial management practices (BMPs) that reduce pesticide application rates or that prevent pesticides from reaching water bodies.

Beneficial Management Practices

Strategies for reducing the risk of water contamination by pesticides include reducing the risk of pesticide transport to surface or ground water, decreasing the amount of pesticide used and reducing the persistence or mobility of the active ingredients.

Because surface runoff and spray drift are important pesticide transport mechanisms, it is critical that pesticides only be applied in suitable weather conditions with the recommended application techniques. Local spray advisory forecasts provide helpful guidance for producers in this regard. BMPs that reduce runoff or soil erosion, or increase soil organic matter content, help reduce pesticide transport. These include riparian buffers, contour farming, strip cropping, and reduced tillage or zero tillage systems. It should be noted, however, that herbicide use typically increases with reduced tillage, which may offset the pesticide-related benefits of the reduction in runoff associated with this practice. Other practices that can help reduce pest pressure include crop rotation and the planting of resistant crop varieties.

Integrated pest management (IPM) combines the use of cultural, biological and chemical control measures, reducing the need for chemical pesticides. Examples of these measures include:

  • cultural techniques and sanitation practices (such as washing soil off equipment when moving from a nematode-infested field to one that isn’t infested, or plowing under infected plant residues) to prevent the development of or suppress harmful organisms;
  • resistant cultivars or certified disease-free seed;
  • practices to protect and enhance natural enemies and other beneficial organisms;
  • scouting and monitoring of crops for the presence of harmful organisms;
  • forecasting systems to inform pest management decisions; and
  • mechanical methods or biological control measures (e.g. biopesticides, natural enemies) when pest pressure reaches the threshold for action.

How performance indices are calculated

The agri-environmental performance index shows environmental performance state and trends over time, based on weighting the percentage of agricultural land in each indicator class, such that the index ranges from 0 (all land in the most undesirable category) to 100 (all land in the most desirable category). The equation is simply "(% in poor class multiplied by .25) plus (% in moderate class multiplied by .5) plus (% in good class multiplied by .75) plus (% in desired class)." As the percentage of land in the "at risk" class is multiplied by zero, it is not included in the algorithm.

The table below shows the index classes. The index uses the same five-colour scheme as the indicator maps whereby dark green represents a desirable or healthy state and red represents least desirable or least healthy.

The index classes
Scale Colour scheme Class
80-100 Dark green Desired
60-79 Light green Good
40-59 Yellow Moderate
20-39 Orange Poor
0-19 Red At risk

The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.

Related indicators

Additional resources and downloads

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