Japanese beetles are an invasive species that can wreak havoc on your garden and landscaping. Japanese beetle damage can be devastating to an avid gardener or even just someone who wants their yard to look presentable.
However, luckily, you are not defenceless to this threat. You have several options when it comes to Japanese beetle control. Keep reading to learn about each control method in detail so that you can make an educated choice about which will be best for you to use against these formidable bugs.
Physical Removal
If you are only trying to protect a small yard or just a few plants in a garden, physical removal may be a viable option. Search your plants for these insects, and if you spot any, grab them or knock them into a container of soapy water. This mixture will kill the beetles with ease without causing any concern for you or your plants.
You will likely be most successful in this endeavour if you search your garden plants in the morning or the evening. While you do not need to remove beetles during this time, they often move slower when it is cooler, and it will be easier for you to catch them around dawn or dusk as opposed to the middle of the day.
If you notice any leaves that have been damaged by the beetles while you are out in your garden, it would be best if you removed these as well. Damaged leaf removal is necessary because, as the beetles feed, they leave behind chemicals that attract more beetles. You will save your plants from future beetle attacks by removing these leaves.
If you wondered if you could flush Japanese beetle larva out of the soil with water, unfortunately, the answer is no. White grubs, as the larva are known, can withstand high soil moisture and actually will soak up that water. When the white grubs hoard all the water, it will deprive your grass and plants of it.
Physical Barriers
In some cases, if you are trying to protect a specific plant, you can put a fine netting over it to keep beetles from getting to it. However, you must be careful not to cover a plant that requires pollination before it has been pollinated.
Unfortunately, these nets will keep out pollinators like bees along with the beetles. It would be best if you waited until the plant starts developing fruit before you cover it.
Traps
You may be thinking that there must be some sort of trap to get rid of these pesky insects. While there are Japanese beetle traps, it is not advisable to use these traps for these invasive bugs.
Unfortunately, most Japanese beetle traps use a synthetic pheromone to lure the beetles to the trap, which often results in more beetles in your garden than there would have been if you did not use a trap.
The Japanese beetle traps are more effective at attracting beetles to your garden than capturing them in the trap. Therefore, unless you want many Japanese beetles around, you should consider a control method other than a trap. Unfortunately, when it comes to Japanese beetles, the thought of using a trap is a trap in and of itself.
Avoid Plants that Japanese Beetles Prefer
You will be much more likely to have to deal with Japanese beetles if you plant the foliage they like to eat. Japanese beetles are not super picky bugs, and there are many things they will eat; however, there are a few species of plants that they rarely touch.
When adding new additions to your garden, you should consider one of the following plants, as recommended by experts, so that you are less likely to have to deal with Japanese beetles.
- Arborvitae
- Boxwood
- Clematis
- Chrysanthemum
- Common Lilac
- Daylily
- Fir
- Forsythia
- Geranium
- Ginkgo
- Japanese tree lilac
- Maple
- Oak
- Redbud
- Rhododendron
- White Poplar
- Yew
If you choose to fill your garden with some of the plants on this list, then you will be less likely to have to deal with Japanese beetle damage in the first place.
Biological Control
If you want to wage a coordinated attack on Japanese beetles, you could consider releasing insects that are a natural enemy of the invasive species. Your options will vary depending on where you are located. For example, two possible choices of bugs in Minnesota that researchers recommend include:
- Istocheta aldrichi (a fly)
- Tiphia vernalis (a wasp)
The fly often lays eggs on adult Japanese beetles while the wasp acts as a parasite on white grubs.
Another option that is more widely available is nematodes. Nematodes are tiny parasitic roundworms that look for white grubs in the soil and will ultimately kill them with a symbiotic bacteria's help. The two most common nematodes in the fight against Japanese beetles are as follows.
- Steinernema glaseri
- Heterorhabditis bacteriophora
Yet another option that can assist in a large-scale effort is milky spore, which is the common name of the bacterium Bacillus popillae. The milky spore has been used since the 1940s; however, it is most successful when deployed as part of a community-wide attack against Japanese beetles.
Note: It is important to know that the bacteria causes milky spore disease in white grubs, which can take up to four years to eradicate a Japanese beetle population.
Pesticides
If none of the above control methods work for you, you may want to try a pesticide. However, you should always use pesticides with caution because they can have unintended consequences. According to experts, here are a few options for you to consider:
- Pyrethrins. This insecticide is useful if it is sprayed directly on the beetles; however, you must be exceedingly careful because this chemical can harm other beneficial insects that are important to the ecosystem, like bees.
- Neem oil. This chemical requires repeat applications, but it is sufficient for small populations of Japanese beetles and is more friendly to bees.
- Bacillus thuringiensis galleriae. This mixture was created from soil bacteria and is reasonably effective for up to two weeks in protecting against Japanese beetles while not harming beneficial insects.
- Chlorantraniliprole. This insecticide provides a bit longer protection by giving you peace of mind for two to four weeks with little risk of harm to bees or beneficial insects.
- Carbaryl. This chemical is another insecticide that can protect for one to two weeks.
- Systemic insecticides. These treatments are absorbed by the plant and provide long-term protection. However, you will likely need to enlist a professional's help to use one of these insecticides. They are usually administered in one of three ways.
- Soil drench
- Trunk spray
- Trunk injection
Conclusion
If you suspect that you have a Japanese beetle problem, it would be best if you developed a Japanese beetle control plan as soon as possible. The sooner you address the problem, the sooner you will eradicate, and the less damage your plants will suffer.