Basil is a staple in my family’s cuisine. But recently, my beloved herbs started suffering from a Japanese Beetle invasion.
I wanted to learn how to keep Japanese Beetles off my basil plants. After some research, I found out that keeping these plants pest-free was easier than I thought.
Here are some effective ways to keep these pests out of your garden.
1. Hand Removal
This method is the easiest and quickest way to address infestations. But, it does require a bit of bravery.
Physically removing the bugs off your plant can do a lot to save existing plants. And if you time things just right, you may be able to reduce future populations.
Japanese Beetles emerge from the soil around June and attack nearby plants. These bugs aren’t picky. They will feed on a wide range of plants. However, they seem to gravitate towards basil and other fragrant plants.
After decimating a plant, they will go into the soil and lay eggs, which hatch into small larvae. The larvae stay in the soil over the winter to emerge the following June.
Keep an eye out for bugs and pick them off the plant. They’re hard to miss. Japanese Beetles have a signature blue-green head and copper-colored wings. The bugs are only about half an inch in size, but their intense color makes them easy to spot.
Check your plants daily and remove as many bugs as you can see. You won’t be able to get them all. But, you can reduce the population enough to make a noticeably impact.
2. Use Insecticidal Soap
If you’d rather eradicate the Beetles without touching them, you can use insecticidal soap.
Insecticidal soap is a unique solution that has been around for a long time. Often thought of as an old-school pest control technique, it still works today.
This product works in a couple of different ways. Physically, the soap can start to break down the bug’s cuticles upon contact. This causes the cells to collapse, which dries the bug out.
It can also coat bugs to suffocate them.
Insecticidal soap products work on a wide range of bugs. Not only that, but it’s an organic solution that doesn’t contain harmful chemicals.
Now, that doesn’t mean it won’t harm your plant. It’s important to dilute the soap as much as possible to ensure that your basil plant doesn’t suffer.
Once your solution is ready, just spray it on the plant. Pay close attention to the foliage. Japanese Beetles like to hide under leaves.
3. Use Garlic Spray
Here’s another chemical-free option that’s usually safe for plants. However, this pest control method works a bit differently.
Rather than creating a formula that will kill the bugs on contact, you’re making your plant unpalatable. Japanese Beetles aren’t fans of the garlic smell.
Spraying your basil with a garlic spray changes the way it tastes and smells to the bug. As a result, they will often move away from the plant and search for something a bit more palatable.
To create your spray, add four cloves of minced garlic to a tablespoon of mineral oil or baby oil. Let this mixture sit for a day before straining the garlic out.
Then, add a pint of water to dilute it.
You can also utilize garlic powder if you’re looking for a quicker solution.
Whatever method you choose, treating your plant is as easy as spraying it down.
4. Use Milky Spore
Want to break the beetle’s life cycle? Try using milky spore.
Milky spore is a unique product surrounded by misconceptions. While this product does appear in commercial insecticide products, it’s completely natural.
This isn’t some random chemical. Milky spore is a naturally occurring bacteria called Bacillus popilliae. This bacteria is soil-dwelling.
During some research, scientists found larvae coated in the stuff. After some testing, they realized that the bacteria caused disease at the larva stage. Thus, the first Japanese Beetle insecticide was born.
Milky Spore does not affect adult beetles. It doesn’t affect any other pest either. Instead, it specifically targets the larvae.
The product comes in powder form and is readily available from most garden centers. When you sprinkle the powder over the soil, you’re putting it right in the path of the larva. They’ll unknowingly consume it and quickly die.
There’s a trick to using milky spore. You can’t use it at any time of the year. The larvae only feed when temperatures are above 65 degrees Fahrenheit.
So, you must apply it in the spring and early fall. Otherwise, it will wash away and have no effect on the young bugs.
This technique takes time to work. But, you’ll be glad you used it when you notice fewer beetles ravaging your basil plants.
5. Apply Neem Oil
If you have any experience with garden pests, you’re likely familiar with neem oil. This trusty pesticide is all-natural and works on a ton of different bugs.
It comes from the fruits and seeds of the neem tree.
The cool thing about neem oil is that it works in many different ways. When the bugs come in contact with it, the oil coats the body. It can cover the breathing holes and suffocate bugs on contact.
The intense smell and flavor can also deter bugs from your plant. But that’s not all.
If the Japanese Beetles are bold enough to continue feeding, they will pay the price later. When ingested, beetles pass the oil onto the eggs. This alters them and prevents hatching.
You can effectively kill adult beetles and prevent them from growing the population. It’s a win-win.
There are a couple of ways to apply neem oil. To use it as a foliar spray, mix about an ounce of it with a gallon of water.
The diluted spray is still powerful enough to kill the bugs. But, it’s also fluid enough to coat the basil plant.
Another option is to drench the soil. The bugs will make contact with it. Furthermore, larvae can eat it and experience the oil’s ill effects.
6. Use Pheromone Traps
Applying a solution, organic or not, isn’t the most appealing to gardeners wanting to harvest their basil. Luckily, trapping is a good solution that has no impact on your plants whatsoever. In fact, you can place the traps anywhere in the vicinity to draw the pests away.
The most effective traps contain vital sex pheromones. Some may also contain fragrant lures that mimic the smell of the bugs’ most favorite snacks.
Whatever the case may be, the traps attract beetles. Once they enter the device, they fall into a compartment that they can’t escape. You can then discard the bag, pop on a fresh one, and continue trapping Japanese Beetles.
It’s important to note that these traps are powerful. That may sound like a good thing, but it could have the opposite effect of what you’re after.
The traps are so effective that they could lure nearby beetles that were nowhere near your garden before. If they don’t get stuck in the trap, they could easily walk away and infiltrate your garden.
7. Attract Beneficial Insects and Birds
Sometimes, all you have to turn to is Mother Nature herself. Many creatures will take care of Japanese Beetles for you. But, you have to get them to your garden first.
Birds are an obvious choice. Birds will pick off the bugs right off your plant to snack on. There is a risk that they will damage your basil, but most birds aren’t going to purposely cause hard.
They want the bugs, not your plant.
The best way to attract birds is to install some birdhouses. You can also try a birdbath or feeder. Place them close to the garden and the birds will come.
Beneficial insects are great, too. One of the best bugs to attract is the Assassin bug. These bugs are predatory and look for weaker insects to hunt. They use their long mouths to stab Japanese Beetles and eradicate them from your garden.
Assassin bugs will appear if you create the right environment. Plant some small flowers around your herb garden. These predators enjoy daisies, dandelions, and other small plants.
You can also install lights and add a source of water.
8. Sprinkle Diatomaceous Earth
Diatomaceous Earth is another old-school pest control product. This powdery substance has been around for almost 200 years and continues to be a go-to for many gardeners.
Readily available online and in stores, Diatomaceous Earth is nothing more than sedimentary rocks. Manufacturers crush the rock to a fine powder consistency.
It’s non-toxic and safe for your plants, too.
This pest control method works similarly to neem oil and insecticidal soap. You sprinkle it on the soil around your plant. When a Japanese Beetle walks on it, the powder starts to destroy its hard protective shells.
Without that shell, beetles will quickly dehydrate. It’s a surprisingly effective method that does a lot of damage. Plus, Diatomaceous Earth works on many different kinds of pests. It’s a catch-all product that can help keep your garden pest-free.
9. Use Beneficial Nematodes
You can’t see them with the naked eye, but nematodes can do a lot of damage. These parasitic creatures eat insects. They actively seek out grubworms and kill it from within.
Many people refer to nematodes as roundworms. Technically speaking, they’re not closely related to worms at all. They are, however, insects. Nematodes just happen to be so tiny that they often move around your garden unnoticed.
Nematodes work to eliminate larvae in a very interesting way. The parasites penetrate the larva’s body. When this happens, it unleashes harmful bacteria. The nematodes have a symbiotic relationship with the bacteria. They rely on it to spread while the bacteria rely on the nematodes to find a food source.
Inside the larva’s body, the bacteria multiply rapidly and start to feed on the grub’s tissue. Eventually, the nematodes will use the larva’s body as a host to reproduce and complete its own life cycle.
Needless to say, this process doesn’t bode well for the Japanese Beetle larvae. It takes time, but the nematode will kill the grub to ensure that it can’t metamorphosis into a beetle and grow the population.
While nematodes are living breathing creatures, they are commercially available from many supplies. The nematode species that are most effective against Japanese Beetles is Heterorhabditis bacteriophora.
10. Fruit Cocktail Trap
Earlier, I talked about pheromone traps and their impact on Japanese Beetles. Those traps rely on chemical signals to lure these pests in. But, you can use a cheaper alternative that’s just as effective.
Japanese Beetles are pests for many different kinds of plants However, many theorize that they gravitate to fragrant foliage and flowers.
You can use this to your advantage and create a trap using a basic fruit cocktail. Available at most grocery stores, the fruit cocktail is sweet and contains many fruits inside.
Grab yourself a can and drain some of the liquid out. Then, prepare the trap. The cocktail alone isn’t going to kill the bugs. So, you’ll need to create a clever trap to prevent them from escaping. A complex contraption isn’t necessary. All you need is a brick and a pail.
Place the brick inside the pail and fill it up with water. Now, set the can of fruit cocktail on top of the brick and put your entire setup about 25 feet away from the garden.
As the fruits bake in the sun, the cocktail will ferment. This creates a strong odor that Japanese Beetles can’t resist. But when they try to access the treat, they’ll fall into the water and drown.
11. Use a Row Cover
If you’re still having Japenese Beetle issues, you can create a physical barrier to prevent them from accessing your plant.
Row covers are simple plastic sheets that protect the plant from outside factors. Think of them as a mini greenhouse.
This method is best for newer Japanese Beetle infestations. But, it might not be effective for existing ones.
Remember, beetles emerge from the soil. After their short 40-day life cycle, they return to the soil to lay eggs and support the population. If you’re dealing with an existing pest problem, row covers may only trap the bugs in.
Make sure to keep an eye on your basil plants to ensure that you’re not just making things worse.
12. Grow Repellant Companion Plants
The last technique is one that takes a lot of dedication. But, it can also be one of the most effective courses of action.
While these bugs seem to feed on anything they can get their hands on, there are a few plants they don’t like. We went over one earlier by mentioning the garlic spray. However, there are a lot of other plants Japanese Beetles detest. Here’s a small collection of examples.
- White geranium
Use this knowledge to your advantage. Add some of these plants to your garden. If you want to create a powerful barrier against Japanese Beetles, use them to plant a border around your basil.
As the fragrances waft through the air, the beetles will have no choice but to migrate away from your garden.