Urrrrrrrg! Japanese Beetles, what can we do about them?
Okay kids, today we are going to talk about Japanese Beetles, how to control them and which methods of control really work. Like Japanese Beetle traps, do they really work? I’ll get to that, but first let’s cover some basics. In order to beat the enemy, you have to know what makes the enemy tick.
Japanese Beetles were first discovered in the United States in or around 1916 and I think it’s safe to say that at that time, an industry was born. The industry of trying to deal with and or get rid of Japanese Beetles really is an industry in itself.
This is what we know about Japanese Beetles.
They “be chillin in the soil” most of the year. Literally, that’s what Japanese Beetles do. They hatch (from below the grass in your yard), they eat, then they mate, then they lay eggs. They they eat some more, mate some more, lay some more eggs. This process really only lasts a few weeks and this party pretty much kicks off at the end of June here in Ohio. Warmer state they party starts earlier.
Japanese Beetles start out as a white grub living in the soil. This is pretty much what their life cycle is like.
1. June and July females mate and lay eggs about 2″ deep in the soil.
2. The eggs hatch into Japanese Beetle Grubs.
3. As the soil temperatures start to cool off the grubs start working their way deeper into the soil. This is how they prepare for the coming cold/freezing weather.
4. Come spring they start ascending toward the surface of the soil.
5. Late June they start to hatch into Adult Japanese Beetles and immediately find something to eat.
6. They have built in mechanisms that allow them to put the word out that the buffet has been located so all new emerging beetles know exactly where to go for a good meal.
7. They eat, mate, lay eggs and repeat the process for several weeks.
8. The adults die and process starts all over again.
Methods of controlling Japanese beetles are as follows.
Along with each method of control I will share with you my opinion of how effective these controls are. These are not just my opinions, I’ve researched this a number of times over the years. But . . . before we get started, you need to know, this isn’t my first rodeo with Japanese Beetles or Japanese Beetle Grubs. We have a history!
1. Picking. You can pick the adult beetles of of your plants and feed them to your chickens. This is sort of, maybe a little bit effective and in a way you know that for each female you pick you have reduced the egg population in your lawn. Each female will lay 50 to 60 eggs, but she does it in small batches of only 5 or 6 eggs at a time. So depending on when you pick her off your plant you are without a doubt reducing the egg population by some number. But we really don’t know what that number is.
However, your chickens will absolutely love your for doing this!
That much we know for sure.
Spraying for Japanese Beetles.
Spraying for Japanese Beetles can be effective but spraying can have an adverse effect on bees, butterflies and other beneficial insects. If spraying is what you want to do your local garden supply store will have a spray you can use. But . . . spraying doesn’t really do anything to reduce the grub populations, so you are only partially solving the problem.
We love biological controls! Don’t we? The only problem is is that they are only so-so effective. Those that use them absolutely swear by them and will tell you that they see immediate results. However, that alone is enough to know that they are imagining these “immediate” results because biological controls don’t deliver immediate results. They are so supposed to deliver long term results.
Bacterial Milky Disease, also known as Milky Spore.
Does Milky Spore Really Work?
The honest answer is . . . yes, to the best of my knowledge it does work. But not the way that people seem to think it works. It takes time. Lots and lots of time. It will take at least two to three years for the milky spore to build up in the soil before it can even think about effectively controlling Japanese Beetle larva in the soil.
Two to three years!
People say to me; “I saw some Japanese Beetles yesterday, I need to make another application of Milky Spore.
That’s just not how it works. You have to apply this stuff in a criss-cross, checkerboard grid pattern all over your lawn. Dumping little piles of this stuff everywhere, so many feet a apart. I think it’s one teaspoon, in a pile, in rows every four feet with the rows four feet apart. Then you have to wait.
Test trials where this stuff has been applied exactly as per the directions have shown documented results. But in other cases, such as in Ohio and Kentucky, similar test applications worked quite poorly.
So, if done perfectly I am inclined to believe that it can work. But . . . and this is the big “butt” during the two or three year waiting period you cannot apply any other kinds of controls of you mess up the natural process of the milky spore. The milky spore needs a fairly heavy population of Japanese Beetles and Japanese Beetle grubs in order for it work as intended. The dead beetle carcases that are killed by the spores release more spores into the soil.
That’s why this is said to be a long term solution because the more beetles that are killed by the spores the more spores are released into the soil and it is self perpetuating.
So if you want to use Milky Spore, then do it right and stay the course!
Can this article get any better?
Anyway, parasitic nematodes are relative new to the scene of Japanese Beetle control and so far, the experts, (universities) are reporting that these Parasitic Nemetodes are marginally effective. Not my words, that’s what the really smart folks at Ohio State University are saying.
What about Japanese Beetle Traps? Do they work?
Here’s the thing with Japanese Beetle traps. If you want results by the pound, then Japanese Beetle traps are the ticket because you will traps pounds and pounds of Japanese Beetles.
But there is a downside to using Japanese Beetle Traps.
Most of them have two different kinds of bait to lure the beetle to the traps. A floral lure and a sexual lure. One for the boys, one for the girls, you guess which is which. These lures are crazy effective! As soon as you even crack open the bait package, you will have company. Guaranteed! I barely peeled the cover off the bait, closed it back up and seconds later this beetle showed up for a little action.
So without a doubt, these Japanese Beetle traps and their super powerful “sexual stimulant” lure will catch beetles by the hundreds if not thousands. But a lot of experts claim that they make the situation worse because they attract beetles from other peoples yards into yours. So if you live in area where your yard is surrounded but the yards of other homes, what you really need to do is get the whole community to set out bait traps and do a “mass trapping”. That is said to work really well.
I will tell you this from my own experience with Japanese Beetles. At home, we live in a small subdivision, all residential properties, lots of landscaping and lots of lawns. At home the Japanese Beetles devour my roses and Harry Lauder’s Walking Sticks. At the nursery, there are a couple of homes nearby, but not a lot of lawn area. Not much for the grubs to eat. I have very little problems with Japanese Beetles at the nursery. It’s residential, heavy turf type settings that make the perfect environment for them.
Why do Japanese Beetles hang out where there are nice lawns?
I’m glad you asked that because I forgot to tell you that Japanese Beetles eat the leaves off your roses and other plants in your landscape, but as soon as that buffet ends the grubs from the eggs they laid in your lawn hatch and the grubs eat the roots off your lawn. Literally. If you have a heavy grub infestation in your lawn, they will devour the roots of your grass and kill your lawn.
But have no fear, because if skunks and moles find out that you have grubs in your lawn they’ll come around and get rid of them for you. Of course your lawn will look like it was rototilled by one of those “BIG” rototillers, but “some” of the grubs will be gone. Not all of them of course, just enough to ruin your lawn and the critters harvest their dinner.
So Mike, what is the Solution?
In my book the solution is to treat your lawn with a good grub control product and kill the grubs when they are small and young and still near the surface of the soil. The ideal time is usually late July, early August. At one time at our other house I had a lot of grubs in my lawn to the point that moles and skunks were digging up my lawn like crazy. I made one or two applications of a good grub control product and that took care of the problem until we sold the house. (See your local garden store of a good granular product)
We still had Japanese Beetles in the yard because of they came from the neighbors lawns, but I got rid of the grubs in my lawn along with the moles and the skunks. As far as I’m concerned this really is the best solution.
Questions? Comments? Post em below.