Nematodes

When is the correct time to put out nematodes to help control the Japanese Beetle larvae?

Thank you,
Suzanne

Anne's Response:

I don't think you want to put out nematodes. I think you want to put out Milky Spore, a bacterium that kills Japanese beetle grubs. I prefer to put it out in early September when the grubs are hatching near the surface of the soil and before they go down to lower levels of the ground for the winter. You can also put it out in early May before the grubs begin to metamorphose into beetles. With the warm weather this February I am seeing some signs of grub activity already so I am at a loss to know when the optimum time would be other than say mid-April might be a reasonable time.