Native Pollinators On Farms
Pesticides used in agriculture include insecticides, herbicides, and fungicides.
Insecticides may affect pollinators (and other beneficial insects) by killing them outright or by causing sub-lethal effects that reduce their ability to forage, communicate, or reproduce. Insecticides are classed as broad spectrum (those that kill a broad variety of insects) or narrow spectrum (those that kill a specific or narrow group of insects). They can be applied as sprays, as coatings on seeds, as soil drenches, or as injections into trees. Many insecticides have a short residual life and are only a risk to pollinators for a few days after they are applied. Others are systemic and have a long residual life, increasing the risk that pollinators will come in contact with them. Systemic insecticides pose an additional risk to pollinators and other nectar-feeding insects because they end up in all parts of a plant, including the nectar and pollen.
Neonicotinoids are a class of insecticides that have been in use since the 1990s. They include 5 active ingredients—clothianidin, imidacloprid, thiamethoxam, sulfoxaflor, thiacloprid, and acetamiprid. They are sold under myriad brand names either singly, stacked together, or stacked with fungicides. To learn more about Neonicotinoids, click here.
You may also be interested in Public Health Ontario's recently published review of the scientific literature on neonicotinoids.
Herbicides affect pollinators and other beneficial insects by removing non-crop flowering plants. These plants often provide reliable sources of nectar and pollen, may be host plants for the larva of monarch butterflies and other butterflies, and may also provide cover for a host of beneficial insects. The widespread use of glyphosate herbicides across the Ontario rural landscape reduces biodiversity of plants and accompanying insect biodiversity and makes foraging more difficult for pollinators.
Fungicides are not known to pose a large risk to pollinators at this time, however there is some evidence that honey bees exposed to agricultural fungicides experience increased susceptibility to Nosema disease.