Q: Hi. Is there some pesticide for hydrangea caterpillars? Or squishing the critters is the only solution? We are in Montreal, Canada.
Allan, I am not sure what is available in Canada and they are regulated and unavailable. If you lived in the United States I would recommend AzaMax by General Hydroponics. Made of azidiractin from the Neem Tree, it is OMRI listed for use in certified organic gardens. It is not a poison but and anti feedant. It's available online and in Hydroponic shops here in the States. Best And Happy Yardening, Nancy