Getting rid of Japanese Beetles on Watercress wasn’t as easy as I thought. Natural remedies only worked temporarily, commercial products didn’t live up to expectations, and there isn’t enough information on the internet.
That’s why I created a list of 12 PROVEN Ways to Get Rid of Japanese Beetles on Watercress.
This ultimate guide is broken down by how to get rid of Japanese beetles on Watercress and how to prevent Japanese Beetles with natural remedies that work, commercial products that live up to expectations, and secrets that only experts know!
What Does Japanese Beetle Damage Look Like?
Japanese Beetles Damage can be quickly and effectively identified. You should look for the following:
- Japanese Beetles on the actual leaves or plant
- Skeletonized Leaves. The part of the leaves between the “veins” of the plants will have lot of holes from Japanese Beetle feeding
- Unhealthy, Brown patches in your yard or garden
- Japanese Beetles flying around your plant or on other plants
12 PROVEN Tips to Get Rid of Japanese Beetles on Watercress Plants
#1. Manually Remove Japanese Beetles
If there are less than a dozen Japanese Beetles…
- Use gloves and manually pick Japanese Beetles off the individual Watercress leaves, and gently drop them into water with a few drops of dish detergent.
- Dispose of the dead Japanese Beetles in a garbage bag. Leaving potentially alive Japanese Beetles behind will just cause a re-infestation.
- After removing the Japanese Beetles you should inspect your leaf or Watercress plant to ensure there are no more Japanese Beetles
- It should be noted that the best time to manually pick Japanese Beetles is around 7pm or early evening. This will help minimize feeding damage to your plant.
If there are more than a dozen japanese beetles…
- Use a glove to gently brush the Japanese Beetles off the Watercress leaves and into a water and detergent solution mix.
- Because Japanese Beetles have wings you should never brush them into the grass. This can cause re-infestation or infestation of other Watercress plants.
- After removing the Japanese Beetles, you should again inspect your leaves and Watercress plants to ensure there are no more Japanese Beetles
- In addition to manually picking Japanese Beetles around 7pm, if you notice more than a dozen japanese beetles on your plant then you can remove these first thing in the morning.
#2. Spray the Infected Watercress Leaves with a Hose
If Japanese Beetles are on your entire leaves…
- Spray the Watercress leaves in the morning with the high power setting on your hose until the japanese beetles are removed. Low power settings or a watering won’t properly remove japanese beetles.
- Then let your leaves completely dry.
- Spray the leaves and your plant in the evening again until the japanese beetles are removed.
- To be safe, it is recommended to repeat the steps every day until japanese beetles are completely gone.
- It is also recommended to follow the same steps with healthy Watercress plants immediately surrounding your attacked plant to help prevent the spread of japanese beetles.
#3. Use Insecticidal Soap
If there are large amounts of Japanese Beetles on your Watercress plant…
- Use an traditional choice for controlling Japanese Beetles, such as Insecticidal Soap.
- Insecticidal Soap is a low-toxicity pesticide made of potassium and fatty acids that have been used by gardeners and farmers for centuries. It can kill large amounts of soft-shell insects like Japanese Beetles without harming your plants, animals, or humans.
- You can also make your own Insecticidal Soap by combining one cup of oil (peanut, vegetable, corn, etc.) with one tablespoon of dish soap. Do not use bleach.
#4. Use Commerical Pesticides
If Japanese Beetles just won’t die then…
- Spray your Watercress plant with a systemic pesticide that contains the chemical, Imidacloprid early in the morning. This is a commercial chemical that is non-toxic to humans and beneficial pollinators, but deadly to harmful insects like Japanese Beetles .
- Repeat applying your pesticide until Japanese Beeltes dead. It should be noted that it can take up to two weeks to fully kill an infestation of Japanese Beetles and prevent them from spreading.
Related: 10 Best Insecticides for Your Garden
#5. Apply an Organic Pesticide
If you Want to Get Rid of Japanese Beetles Organically…
- Then create your own organic pesticide. You can create it by doing either of the following:
- Mix 3 teaspoons of dish soap with 1 quart of water. You can either spray or gently apply this solution onto your Watercress leaves
- Mix 1 teaspoon of dish soap, 1 teaspoon of cayenne pepper, and 1 quart of water.
Like a commercial pesticide, you should apply this solution to your Watercress plants in the morning until the Japanese Beetles infestation is gone. Again, it may take two weeks to kill your infestation and it is not as effective as chemical pesticides.
It should be noted that while organic pesticides are almost guaranteed safe to you, children, and animals, it is typically not as effective as commercial products.
Do Not Use…
- Coffee Grounds, Banana peels, or any other home remedy that you may read about.
While you may read about these remedies in other articles there is little scientific evidence that they are effective and can even attract other insects or garden pests.
#6. Apply Neem Oil
The Most Effective Way to Prevent Japanese Beetles is to…
Apply Neem Oil
- While you can make your own organic neem oil it is recommended to mix commercialal Neem Oil with water in a garden sprayer and apply it onto all your fruit and vegetable trees in mid to late winter immediately before the last frost.
*Commercial neem oil is as safe as diy neem oil*
Find your last frost date HERE.
You will need to spray your Watercress plants several times before the spring to destroy japanese beetle eggs and repel mature japanese beetles. Neem Oil will not kill beneficial insects with hard shells and bees.
#7. Plant Trap Crops
If Pesticide doesn’t work…
- Plant Trap Crops
- Plant a row of plants in another part of your yard that Japanese Beetles love and will be attracted to. Japanese Beetles will then leave your Watercress plants alone.
- The best plants to grow to attract Japanese Beetles are marigold, borage, geraniums, primrose, and knotweed.
#8. Use Dead Japanese Beetles
If You Don’t Want to Spray Japanese Beetles then…
- Use dead Japanese Beetles to repel live Japanese Beetles
- Make sure you place a container of dead Japanese Beetles right next to your Watercress plant you want to protect
#9. Use Row Covers
If Japanese Beetles have spread to your Watercress plants in the past then..
- During peak feeding season, protect your Watercress plants with row covers.
- You should keep your Watercress plants protected from mid-day to the end of July. This will not only prevent Japanese Beetles from attacking your plants, but also cause them to leave your garden alone.
#10. Attract Beneficial Animals
If you don’t want to use spray…
- Then grow Watercress plants that will attract birds, tachinid flies, and nematodes.
- These bugs and birds are the best at most effectively and quickly eating and getting rid of japanese beetles.
Tachinid flies and nematodes are the best type of insects to eat and destroy Japanese beetles eggs, larvae, and even adult beetles.
Birds like cardinals, robins, and catbirds are the best animals to attract to eat and destroy large numbers of adult japanese beetles.
Not only are beneficial insects great to help get rid of japanese beetles, but they are essential in preventing japanese beetle infestations.
#11. Don’t Water Your Lawn
From June through July you should keep your grass minimally watered.
This is because Japanese Beetles prefer well-watered grass for laying their eggs.
By letting your grass go dormant the Japanese Beetles will stay away from your yard and Watercress plants.
#12. Aerate Your Lawn
- The best way to get rid of Japanese Beetles on your Watercress plants is to kill them while they are still grubs.
The best way to get rid of Japanese Beetles is to aerate your lawn in the fall. By aerating your lawn in the fall you will kill all the Japanese Beetle grubs that are feeding towards the top of the soil. This will not only kill japanese beetles, but will also prevent them.
As a reminder, there are 12 Proven & Effective Ways to Get Rid of Japanese Beetles on Watercress. They are:
- Manually Remove Japanese Beetles
- Spray Leaves or the Watercress Plant that has Japanese Beetles
- Use Insecticidal Soap
- Use Commercial Pesticide
- Apply an Organic Pesticide
- Attract Beneficial Animals
- Plant Trap Crops
- Apply (commercial) Neem Oil
- Use Cover Rows
- Don’t Water Your Lawn
- Aerate Your Lawn
- Use Dead Japanese Beetles