Jan from Marana, Arizona writes
Infested with black gnats in house plants. Can I spray on the dirt in planters to kill?
Monterey Once A Year Insect Control II is not labeled to control gnats. The best option for gnats in houseplant soil is to allow the soil to dry out completely if possible as this will kill any larvae in the soil. Otherwise you can drench the soil with something like Bifen I/T or Evergreen.
Answer last updated on: 03/26/2019