These recipes for home-made pesticides (for domestic use) are given for information purposes only. The Montréal Botanical Garden does not guarantee their effectiveness.
The Montréal Botanical Garden recommends extreme caution when preparing, handling, using and storing any pesticides, including home-made ones. Some products can be hazardous even if they are « natural ».
Wear protective gloves, goggles and clothing. When preparing, applying and storing home remedies, it is best to use tools (containers, spray bottles, etc.) reserved for this purpose. Mark all home remedy storage containers clearly and keep them out of reach of children.
Before treating an entire plant, test the mixture on a few leaves and wait 24 to 48 hours to see if there are any signs of phytotoxicity (discoloured, stained, wilted, dried or dropping leaves). If so, do not treat the plant.
Avoid treating plants on windy days, in full sun or during a heat wave or dry spell.
These recipes are not selective and may destroy both useful and harmful organisms.
http://www2.ville.montreal.qc.ca/jardin/en/info_verte/fiches/pesticides_nat.htm