Will spraying soapy water on Japanese beetles kill them? I see flocks of...

Asked April 13, 2019, 11:20 AM EDT

Will spraying soapy water on Japanese beetles kill them? I see flocks of black birds (grackles) feed under tree known to have Japanese beetles larvae in the ground, are they eat the grubs? Way to encourage the birds?

Hennepin County Minnesota insect pests japanese beetles

1 Response

Thank you for the question. Spraying adult beetles with soapy water will not be very effective in controlling beetle numbers. Extension advises knocking the beetles into a jar or bucket of soapy water. In this way, they can't fly away and they can't release the pheromones that attract other beetles to your location.
Learn more about non-chemical methods of control here:
This Colorado Extension publication is also excellent and lists chemical control methods:

This publication lists birds known to eat the beetles and grubs. Grackles are listed: http://www.uky.edu/Ag/PAT/recs/crop/pdf/entfa409.pdf

There are many good books on how to attract birds to the home landscape. Essentially what's needed is food, water, shelter, and nesting sites.

Thank you for contacting Extension.