In part one we established the damage that can be caused to your garden by both the Japanese beetle grubs and their adult counterparts. Unchecked, they can leave your lawn and garden plants not only unsightly but unhealthy as well.
When trying to find an effective, natural, solution you don’t have to look any farther than nematodes!
Believe it or not, nematodes are part of the same family as ring worms. But don’t let that scare you; beneficial nematodes pose no threat to humans, pets, or plants. Instead they seek out insect larvae using small changes in soil temperature or carbon dioxide emissions to locate them. Once found, they enter the grubs and kill them with the bacteria they carry in their stomachs in just 48 hours!
Once the grub is dead, the nematodes (which have now multiplied several times in the host) begin to feed until the grub is consumed. When there is nothing left, the nematodes continue their search until they find a new host.
Nematodes are a great choice for grub and Japanese beetle control for these reasons:
- They are a natural, chemical-free alternative to other harsh products.
- Both the nematodes and the bacteria they carry pose no health risks to humans or pets.
- They are cost effective.
- As long as they have been applied correctly, they are very effective at eliminating infestations.
- In addition to the Japanese beetle, nematodes also target the European chafer, common chafer, Asiatic beetle, May and June beetle, black vine weevil, strawberry root weevil as well as other insect pests that live in the soil.
Once the grub infestation has been stopped, they nematodes themselves simply die off and decompose to become part of the organic matter of the soil. The bacteria they carry also dies off, as it cannot survive outside of their bodies for long.
Now that we know what nematodes are and how they work, how do we use them?
For best results, nematodes should be used twice a year, to follow the life cycle of the grubs themselves; once mid-May, and then again in September. As nematodes are living organisms, application should be done within 2 weeks of purchase and the containers must be kept in the refrigerator (not freezer!) until use.
The exact time to apply depends more on soil temperature and the maturity of the grubs than the date itself, and the nematodes are most effective when the soil is between 14°C and 33°C.
To use, first moisten the lawn well before adding the nematodes to a water mixture (according to the package instructions). Once applied, water the lawn thoroughly to ensure the nematodes penetrate the soil; bearing in mind the lawn must be kept watered for between 4-7 days after application.
You will know the nematodes were successful when after about 7-10 days any grubs found have begun to turn from white to reddish-brown.
Applying nematodes can be done by anyone, however, if you are unsure or the grub infestation is bad enough, talk to your local lawn and garden experts! They can offer tips on application, or even provide the service themselves. And trust us, it’s worth it: no grubs = no Japanese beetles!