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Letter to the Ministry of Forests, Wildlife and Parks and the Ministry of the Environment and the Fight against Climate Change: Request for a moratorium on the use of Bti larvicide

Montreal, May 19, 2021

Mr. Pierre Dufour, Minister
Ministry of Forests, Wildlife and Parks
5700 4th Avenue West
Quebec (Quebec) G1H 6R1

Montreal, May 3, 2021

Mr. Benoit Charette, Minister
Ministry of the Environment and the Fight against Climate Change
Marie-Guyart Building
675 René-Lévesque Boulevard East, 30th floor
Quebec (Quebec) G1R 5V7


Subject: Request for a moratorium on the use of Bti larvicide


For more than 35 years now, our waterways and wetlands have been sprayed each summer with Bti, a still little-known insecticide mainly causing the death of aquatic larvae of stinging insects. Bti owes its name to a bacteria naturally present in soil. This bacteria, once ingested, produces microscopic crystals in the intestine of the larvae and triggers a toxic reaction ultimately leading to their death. However, this bacteria only represents on average 7 % of the commercial formulation currently applied. A cocktail of products whose recipe is protected by industrial secret is combined to increase its effectiveness, such as, for example, protective agents against ultraviolet rays. It is therefore difficult to describe this insecticide as “organic”. Furthermore, unlike most insecticides spread on cultivated soils, Bti is applied directly into our waterways: one of our greatest assets that we must treat with caution.

Bti has long been considered environmentally safe, believing that its mechanism of action was sufficiently complex and specific to only target biting insects. However, recent independent studies have demonstrated that Bti can directly and significantly affect the size of chironomid populations (Allgeier et al. 2019, Kästel et al. 2017). As this group of insects constitutes a prime food source for many birds and amphibians, the size and development of these organisms may be affected (Empey et al. 2021). Such a disruption of the balance of the food chain is worrying for the integrity of our aquatic ecosystems. The cumulative effects of all land application projects do not appear to be monitored or documented. These concerns are detailed in a guidance document produced by your ministry some time ago. It also highlights a lack of Canadian studies regarding the impacts on wildlife and the food web. However, more than 40 municipalities currently hold spraying authorizations issued on the basis of wildlife notices produced by your ministry. On the other hand, several citizen groups have raised significant concerns about the relevance of such spraying and their impacts, accompanied by various studies.

At the commercial level, the Quebec Bti spreading industry is a duopoly made up of only two companies (GDG Environnement and Roy Forestry Advisors). This lack of competition is potentially problematic for sound management of municipal finances.

Several alternatives to spraying exist for controlling biting insects. These appear less damaging to our natural environments and significantly less costly (e.g. traps, garlic, nest boxes, etc.). In addition, their scope can be modulated by targeting only habitable spaces, thus avoiding the spreading of a biocidal substance in our waterways.


  • A moratorium on the issuance of spreading authorizations while a review of the ministerial position is produced;
  • recognition of the preponderance of the precautionary principle given the decline in populations of birds, amphibians and insects on Quebec territory pending the next government policy;
  • recognition of the effectiveness and safety aspect of alternative control methods so that the municipalities most seriously affected by the nuisance caused by biting insects can use them;
  • to the MFPP: a review of the MFFP's position on Bti in light of new independent knowledge acquired around the world over the last two decades and presented in part in the MFFP orientation document produced in 2019;
  • to the MELCC: a review of the MELCC's position on Bti dating from 1997, updated in 2004, in light of new independent knowledge acquired around the world over the last two decades and in collaboration with the MFFP.

Thanking you for your attention to this letter, we remain available for any additional information.

Please accept, Mr. Minister, the expression of our distinguished greetings.

Alain Saladzius, P.Eng., FIC


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