Here’s A Flight You’ll Want to Miss

Here’s A Flight You’ll Want to Miss

For growers around the world, there are certain seasons that can be more stressful than others. In the U.S. the challenges of the seasons are no different. With the ever evolving globalized market of the world, the challenge of keeping unwanted pests out seems to get harder every single year. 

This challenge is especially difficult during their mating seasons when many pests reproduce and establish their damages for years to come. One pest in the United States is regarded with high priority for eradication and control methods. 

Every year between June 1st until September 30th growers around the U.S. work tirelessly to seek an end to the damage from the Japanese Beetle. This time of the year is known as the Japanese Beetle Flight Season (Period).

Japanese Beetles- A History

As you could probably guess by the name, the Japanese Beetle (Popillia japonica)originated in Japan. Many, many years ago in 1916 Japanese Beetles were officially discovered in the United States near Riverton, New Jersey.[1] However, it is believed that the pest made its way over on a shipment of Iris bulbs as early as 1912. [2]

Fast forward to the current year of 2020 and most states East of the Mississippi River have been infested by the Japanese Beetle. While partial infestations do exist West of the Mississippi, states on that side of the U.S. have taken strict precautions to protect themselves against the spread of the invasive pest. [1]

What’s the Big Deal With the Small Size?

While the establishment of Japanese Beetles is fairly well known at this point in time, many of you may still be asking “Why are these pests such a big deal?”

Japanese beetles can prove difficult to remove once they’ve established themselves at a location. 

During their flight season, the beetle digs a hole in the soil and lays their eggs. The growing beetles, or grubs, will then spend the next 10 months in the soil before emerging. During their time in the soil the grubs devour roots and seedlings of good quality turf and vegetables. While the grubs prefer good quality turf and vegetables areas, they can survive in almost any soil conditions. 

While the grubs wreak havoc below ground, above the surface the Japanese beetle can do just as much damage. As can be seen above, the Japanese beetle will eat out the green tissue between the leaf veins of a plant for feeding. This is consistent with their feeding pattern and not particular to one type of plant. While the plant may recover from the damage to their energy panels, or leaves as you may call them, the damage leaves the plant more susceptible to damage from other harmful insects and pests.

How Do I Know If I Have Them?

While the beetles are growing and in their grub stage, it can be difficult to know whether or not you have an infestation. But, above the surface things are much more noticeable. 

The Japanese beetle tends to “appear out of nowhere.” One day you may have seen 0 pests, and the next day they may be overwhelmingly apparent! There are a few plants that, depending on region, may act as indicator plants, or plants that are of preference to the Japanese beetle. They can almost certainly be found in rose bushes of any kind, raspberry plants, Linden trees, Maple tree varieties, Fruit tree varieties, Elm tree varieties, Ash tree varieties, Oak tree varieties, grape vines, and many more.

When “planting” their eggs in the soil, the female Japanese beetle follows a fairly specific pattern. She will take flight in the afternoon. She will find moist soil conditions. She will then dig and bury her eggs 2-3 inches in the ground. From there the lifecycle of the Japanese beetle starts all over again. 

But let’s take a step back to the identification of “moist soil conditions.” As I mentioned above, the Japanese beetle grubs prefer quality turf roots for feeding, because of this, the female beetle also looks to identify wet turf conditions for laying her eggs. The wet conditions are ideal and somewhat essential to the larvae stage of the beetle. It isn’t until the grubs are older that they are more drought tolerant, and before then it is pertinent to their survival. [4]

With all of the factors of preference for larvae livelihood considered, there are some key indicators that can help determine if an infestation is possible, or already exists. Moist irrigated turf areas are an ideal habitat for the grubs. When large portions of the turf die during times of hot and dry weather it can be a strong indicator that there is a larvae infestation. 

Treatment Options for Japanese Beetle

The Japanese Beetle once fully grown only lives for about 30-45 days at a time. So, when treating for the pest, targeting the larvae stage is just as important as eradicating the adult stage.

With a feeding habit that includes over 300 different plant species, the treatment options for Japanese Beetles is just as vast as the types of plants they eat!

There are chemical options available using different active ingredients such as Bifenthrin, Chlorpyrifos, Imidacloprid, Methyl Bromide, Lambda-cyhalothrin, Cypermethrin, and many more. Many greenhouses are required by law to use different chemicals in order to ship their plants across state borders during the Flight Period. 

This is seen as perhaps the most effective method against the Japanese beetle and is helpful in mitigation of the larvae stage, as well as the adult stage. However, because the beetles hatch in stages, while you may have sprayed one day for the insect, the insects may continue to emerge over time. 

Other options for treatment include using traps that utilize pheromones to attract the insect, but you can end up with more insects than you started with. There are also pellets that can be applied to grass areas that target the larvae specifically. We personally prefer the slow release pellets that are designed to prevent groundwater contamination. Another option for treatment is to physically pick them off your plants and drop them in a bucket of water as they’re collected.  

Whatever method of treatment you decide is right for your environment, be sure to do your research beforehand as to what is going to be best for your plants and their surroundings. The ultimate goal is to always have the healthiest plants, and too much of one thing can lead to not enough of another.

Plant Sentry™ Involvement

We like to think we’re kind of a big deal, and honestly it’s because we are! When it comes to pest mitigation the Plant Sentry™ experts work year round to stay up-to-date with the latest pest treatments. With involvement of different plant boards around the United States, members of Plant Sentry™ strive to stay up-to-date on the latest treatment methods for the Japanese Beetle. 

With our expertise we’re sure to help you ship the healthiest of plants. To learn more about how you can gain access to this information visit our contact us section!


[1] Japanese Beetle Harmonization Plan. (2018, December 04). Retrieved June 30, 2020, from

[2] (n.d.). Retrieved June 30, 2020, from

[3] Japanese Beetle Lifecycle Illustration. (n.d.). Retrieved July 01, 2020, from

[4] Japanese Beetles in the Urban Landscape. (n.d.). Retrieved July 01, 2020, from