November 25, 2014; Ontario Ministry of the Environment and Climate Change
Reducing the Use of Neonicotinoid Insecticides to Protect Pollinators
Why are pollinators important?
Pollinators play a critical role in agriculture and the natural environment. Many crops and flowering plants that depend on pollinators are important sources of food, habitat, shelter and other resources for people and wildlife. Most plants can't produce seeds and fruit without the pollen transferred by pollinators.
With more than 700 native species in Canada, bees are the most common pollinator. Both managed and wild pollinators play a critical role in the production of most fruits and vegetables and reproduction of flowering plants.
Ontario's honey bees pollinate about $897 million of the roughly $6.7 billion in total sales for agricultural crops grown in the province -- about 13 per cent of the total crop value. In Ontario, 3,000 registered beekeepers operate 100,000 honey bee colonies. The honey produced by these bees is a $26 million industry. In addition, Ontario honey bee colonies are transported to eastern Canada to pollinate about $71 million of the blueberry and cranberry crops.
Why do pollinators need to be protected?
Bees and other pollinators may be experiencing pressure from four main areas: loss of habitat and nutrition; pesticide exposure; climate change and weather, disease, pests and genetics.
Ontario beekeepers have experienced unusually high losses of honey bee hives over the winter, reaching 58 per cent this past year. Overwinter die-offs of honey bees averaged 34 per cent over the past 12 years. The level considered acceptable and sustainable by beekeepers is 15 per cent.
There has also been an increase in reports of high colony mortality rates during the summer months. In 2012, approximately 240 bee yards reported bee deaths. This rose to 340 yards in 2013. The federal Pest Management Regulatory Authority (PMRA) reported that approximately 70 per cent of dead bees tested in 2012 and 75 per cent tested in 2013 contained residues of neonicotinoid insecticides.
There are many factors that can affect pollinator health. Taking action to reduce exposure to neonicotinoids is one factor which can be addressed in the short term.
What are neonicotinoids?
Neonicotinoids are a class of synthetic pesticides that are chemically similar to nicotine. They are neurotoxins and affect the cells in the nervous system of animals. While neonicotinoids target insect pests, they can also harm other beneficial insects, such as bees.
The PMRA has determined that "current agricultural practices related to the use of NNI treated corn and soybean seed are affecting the environment due to their impacts on bees and other pollinators." PMRA concluded that these practices are "not sustainable".
Neonicotinoids are a relatively new class of insecticides. Over the past decade, the use of neonicotinoid-treated seed has significantly increased -- almost 100 per cent of corn crops and 60 per cent of soybean crops in Ontario use them. Neonicotinoid-treated seeds are often used as a preventive measure, without evidence of pest problems. There is little evidence to show that soybean seed treatments provide overall benefits to production in most situations. The U.S. Environmental Protection Agency concludes that "in most cases there is no difference in soybean yield when soybean seed was treated with neonicotinoids versus not receiving any insect control treatment."
Bees and other pollinators may be exposed to neonicotinoids from a number of sources, including spray, dust from treated seeds, residue on plants and through contaminated pollen, nectar and water.
Three neonicotinoids (imidacloprid, thiamethoxam and clothianidin) are considered to be highly toxic to bees and have effects at very low levels.
These types of neonicotinoid insecticides are:
=> Pervasive and systemic - spreading throughout the plant making all parts of the plant harmful to insects feeding on them.
=> Persistent - do not break down quickly in soil and remain for months after application. Some neonicotinoid insecticides can break down into more toxic forms.
How does exposure to neonicotinoids affect pollinators?
As they are insecticides, neonicotinoids are toxic to insects, including beneficial insects, like bees. Neonicotinoid exposure at prolonged low levels (known as chronic exposure) has been shown to affect the ability of bees to gather pollen, navigate (return to their hives), and reproduce. Research also shows that neonicotinoids may impact colonies when residues are brought into the hive from bees that return from collecting food.
What is the environmental impact of neonicotinoids?
The federal PMRA has determined that "current agricultural practices related to the use of NNI treated corn and soybean seed are affecting the environment due to their impacts on bees and other pollinators."
A recent review of 800 scientific papers on studies conducted around the world found that neonicotinoid levels frequently exceed amounts known to have adverse impacts on a wide range of non-target species.
It is possible for neonicotinoids to run-off from fields to nearby water bodies where they can cause harm to aquatic insects and affect the animals that feed on those insects. There is also some evidence indicating the potential for neonicotinoids to have broader environmental impacts, including effects on birds and earthworms. With this growing information, we are taking precautionary steps to reduce neonicotinoid-treated seed in Ontario.