Thanks for your question. It is not an easy one to answer when your say “environmentally safe”. To find something that gets rid of grubs without affecting any other living creature is not really possible. You are correct about the use of nematodes. That approach has had mixed success in Minnesota. All I can do is to direct you to the following which is the best scientifically based advice that I can find:

https://extension.umn.edu/yard-and-garden-insects/japanese-beetles - non-chemical-management-options-1591111

https://extension.umn.edu/news/japanese-beetle

https://pepin.extension.wisc.edu/files/2010/10/Hort-Japanese-Beetle-Management-in-Minnesota.pdf

I am sorry that I cannot provide you with a “magic bullet” by which to deal with this pest. Unfortunately there just isn’t one.

Thanks for consulting us.

Thanks for getting back to us. For us to assist you further, we have to identify the type of insect with which we are dealing.  There are many beetles that fit your description.  To provide you with meaningful and accurate information, we would need to see a picture of either the beetle or the grub.  We understand that this may not be possible to obtain at this time (mid-April 2024).  If and when you are able to do this, we would be in far better position to assist you.  We also note that you asked a question regarding grubs last October (2023).   At that time a definitive answer could not be provided to you since no identification was made of the grubs. 

Thanks again for reaching out to us.

Will look forward to receiving any pictures you are able to send.

Thanks again for consulting us.

Thanks foe your patience.  I am consulting an entomologist regarding things.

Thanks for using our forum,

Thanks foe your patience.  I am consulting an entomologist regarding things.

Thanks for using our forum.

Thanks for the pictures.  I am, however, slightly confused.  Are these pictures of grubs from your lawn or pictures of grubs/beetles from some place else?  If the latter, then it would be helpful to see a couple of pictures of grubs from your yard.   The best way to do this is to lift up a piece of sod and see if any grubs are underneath.

Thanks for continuing to consult our forum.

Thanks for your last response and especially for the pictures.

The beetle on the left of the three pictures looks like a type of Chafer beetles. They are sometimes called May Bugs or June Bugs. It might even be the European Chafer that was first reported in Minnesota about four years ago. These types of beetles overwinter in the soil as adults. Depending upon the exact species, these adults emerge from the soil in late May extending into early July. These adults quickly mate and lay eggs that develop into white grubs. These grubs will destroy the roots of many plants including turf grasses. These grubs can be detected as early as June and extending into August. Here is some information about this type of beetle:

https://apps.extension.umn.edu/garden/diagnose/insect/general-curiosity-insects/beetles/medium/may-june-beetles.html

https://www.mda.state.mn.us/plants-insects/europeanchafer

https://patch.com/minnesota/southwestminneapolis/invasive-lawn-eating-beetle-makes-way-minnesota-1st-time

The middle picture of the three pictures is a chafer beetle grub. See the following:

https://extension.umn.edu/corn-pest-management/white-grubs

The right picture of the three pictures is an adult chafer bug.

We now know that Japanese Beetle grubs are not the culprits. The window of time to deal with the chafer grubs will then run from late May into August. This is the period during which chafer grubs will be the most active and most susceptible to intervention. Although the following deals with Japanese beetles, it also is true for chafer bugs. Please note that this site will also describe the types of chemicals that can be used in addition to the more natural use of beneficial nematodes:

https://pepin.extension.wisc.edu/files/2010/10/Hort-Japanese-Beetle-Management-in-Minnesota.pdf

I do not have any direct experience with Johnathan Green Natural Grub and Insect Control. What little I found is contained in the following:

https://www.bestproductsreviews.com/best-grub-killer?targetid=kwd<personal data hidden>61&matchtype=b&device=c&campaignid=<personal data hidden>&creative=<personal data hidden>8&adgroupid=<personal data hidden>3&feeditemid=&loc_physical_ms=9019792&loc_interest_ms=&network=g&devicemodel=&placement=&keyword=$best grub killer&target=&aceid=&adposition=&trackid=us_all_top_1_1&mId=<personal data hidden>&trackOld=true&gad_source=1&gclid=CjwKCAjw9IayBhBJEiwAVuc3fk_XpDmOhfD0J9O_8BIdIZA-rkQa_0o13CH-0KYyjMHOZKS1jsnlLhoC7T8QAvD_BwE

Perhaps the best advice I can provide you is to use a variety of different grub control processes. Use both natural as well as chemical approaches. Some may work and some may not. Complete elimination of these grubs probably will not occur in a single year. It will require patience and experimentation on your part.

Good luck. Of course, if you have further questions, please get back to us. Thanks for using our forum.

I think you are now on the correct track.  Good luck, keep us apprised.  Thanks again for using our forum.

We are here to help you so don't hesitant to get back to us about how things are going.