Using One Pest Against Another

David Trammel's picture

For urban gardeners, Japanese beetles are a scourge. You can try traps, cull by hand, or sprinkle grub-killing poison. Even then it can seem like a losing war. Here's one person's solution, encourage the moles to eat the grubs.

"When we first started our veggie garden, we used to have a LOT of adult Japanese beetles, mostly in June. They loved our garden and for a couple of years, our veggie garden and ornamental plants suffered greatly, mainly because I was determined to not use pesticides but didn’t know what the heck to do about the Japanese beetles because I didn’t understand their lifecycle.
But then we decided to dump having a “real” lawn. We just let the weeds, clover, and natural grasses grow into a nice green yard…no fertilizing….no seeding (except clover) …. no watering, except during drought. That’s what you can do when you don’t have subdivision mandates on lawns and gardens.

The Japanese beetle grubs didn’t seem to like that “mixed-lawn”. anywhere near as well as our former turf lawn. Not as many roots to eat on, I guess Plus three (might have been four) little moles suddenly started hunting in our yard….CUTE little guys. They really LOVED those Japanese Beetle grubs! We would leave most of the mole tunnels alone except for those that were in our heavy traffic walking areas. In those, I would do a convoluted walk, crushing the more inconvenient (to us) mole tunnels so that that we wouldn’t stumble over them and break a leg. Regularly caving in a few of their tunnels didn’t seem to deter the moles…they would just move to another area, but come back if any grubs were left. Excellent hunters. We “herded” those moles over our entire large yard for two summer seasons.

Note that we did put in resistant barriers to the moles around our garden though…very important point!

So we left the moles to their wanderings for two years in a row. After a couple of years of encouraging moles to eat ALL the grubs in the lawn, we did not have any more adult Japanese Beetle infestations and haven’t seen any but a few of the beetles for 7 years now. I figure that we just created a nice population balance between humans, moles and beetles….at least for now. Since our beetle population went down dramatically (who knew three moles could eat so many grubs?), we assume that the moles left for the adjoining woods from whence they had originally come, looking for other grub food sources. I’m sure they check back every now and then to see if the Nirvana of Japanese Beetle grubs has returned to our lawn.

It’s been a win-win for everyone. We humans have now lived with a much reduced population of adult beetles for the last 7 years. (knock on wood). And the moles had two gangbuster seasons of grubs for food. And even the beetles had a win (overpopulation isn’t productive for ANY species). Nature in balance. Can’t beat it.

Working with Nature.

Sweet Tatorman's picture

I am a bit skeptical of this post based upon my experience with moles and Japanese beetles. I have had large populations of both for many years. While I squash 100's of Jap beetles between thumb and forefinger every year I have no idea of the number of moles as they are never seen with the rare exception of killing and turning up one with the tiller. I do infer that they are numerous as their tunnels and soil mounds are everywhere.
Somewhat in the spirit of the original topic (though I do not consider my helpers to be pests) I am happy to coexist with skunks which eat all manner of garden pests including various grubs such as Jap beetles and cutworms. I am especially blessed this year as there are two families of skunks foraging around the garden but not within due to electric fencing. Baby skunks are really cute. Yesterday I took a camp chair and a cold beer out to watch 3 of the babies go about their skunk foraging business for a long while. They really stay on task. I walked over and snapped a photo of the one below. Despite the all white top of this individual these are striped skunks (Mephitis mephitis). It was so focused on it's task of grubbing for grubs I had to shout at it to get it to look up for a photo op.

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