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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 every summer with Bti, a still little-known insecticide that mainly causes the death of aquatic larvae of biting insects. Bti owes its name to a bacterium that is naturally present in soils. This bacterium, once ingested, produces microscopic crystals in the intestine of the larvae and triggers a toxic reaction ultimately leading to their death. However, this bacterium only represents on average 7 % of the commonly applied commercial formulation. A cocktail of products whose recipe is protected by industrial secrecy is combined with it to increase its effectiveness, such as, for example, protective agents against ultraviolet rays. It is therefore difficult to qualify this insecticide as "biological". Moreover, unlike most insecticides spread on cultivated soils, Bti is applied directly to our waterways: one of our greatest assets that we must treat with care.

Bti has long been considered safe for the environment, believing that its mechanism of action was sufficiently complex and specific to target only biting insects. However, recent independent studies have shown 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 is a primary food source for many birds and amphibians, the size and development of these organisms can be affected (Empey et al. 2021). Such disruption of the balance of the food chain is of concern for the integrity of our aquatic ecosystems. The cumulative effects of all spreading projects do not appear to be monitored or documented. These concerns are detailed in a guidance document produced by your department some time ago. It also highlights a lack of Canadian studies on wildlife and food web impacts. However, more than 40 municipalities currently hold spreading authorizations issued on the basis of wildlife advisories produced by your department. On the other hand, several citizen groups have raised significant concerns about the relevance of such spreading 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 Conseils Forestiers Roy). This lack of competition is potentially problematic for sound management of municipal finances.

Several alternatives to spreading exist for the control of biting insects. These appear to be less damaging to our natural environments and much less expensive (eg trap, garlic, nesting 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 until a review of the ministerial position is produced;
  • the recognition of the preponderance of the precautionary principle in the face of the observation of the decline of the populations of birds, amphibians and insects on Quebec territory pending the next government policy;
  • the recognition of the effectiveness and the safety aspect of alternative control methods so that the municipalities most strongly affected by the nuisance caused by biting insects can resort to them;
  • to the MFPP: a review of the MFFP position on Bti in the light of new independent knowledge acquired around the world over the past two decades and presented in part in the MFFP policy document produced in 2019;
  • at the MELCC: a revision of the MELCC position on Bti dating from 1997, updated in 2004, in the light of new independent knowledge acquired throughout the world over the past two decades and in collaboration with the MFFP.

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

Please accept, Minister, the expression of our best regards.

Alain Saladzius, P.Eng., FIC


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