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How to Get Rid of Japanese Beetles

Batul Nafisa Baxamusa
Japanese beetles were accidentally imported to America from Japan. This destructive beetle has become a serious pest in lawns, orchards and gardens. If your garden or lawn is facing a threat from these tiny weapons of mass destruction, then you need some methods to get rid of them.
Japanese beetles were discovered in New Jersey in the year 1916. Since then, they have spread across the northeastern states of America. The climate in U.S. is found to be particularly suitable for these insects. However, British Columbia and the western States of Arizona, California, Idaho, Nevada, Oregon, Utah and Washington are presently free from them.
These seasonal pests are 8-10 mm long and metallic green to greenish bronze in color. They have coppery red wings and small white tuffs on the sides and tip of the abdomen.
The larvae are 20-25 mm long. When they mature they develop a 'C'-shape. These destructive plant pests feed on the foliage and fruits of hundreds of plant species. They eat and destroy fruit trees, shrubs, vegetables, field crops and ornamental plants. They leave behind skeletonized leaves with large, irregularly shaped holes.
The grubs(larvae) grow in the soil. They eat the roots of different plants and grasses. This destroys the turf in the parks, lawns and golf courses. If there are about 5 to 6 grubs per square foot of your lawn or garden, then it is definitely the time to take some action and control their growth.
There are many chemical pesticides that will effectively kill the grubs and adult beetles. You can even try organic methods as an effective way for pest control.

Controlling Grubs

  • You can get rid of the grubs by spraying the garden or yard with "Milky Spore" powder. This powder has bacteria that is ingested by the grubs. The bacteria multiply in the grubs till they die. You can use this method once in late July to early August.
Although, this may not show a significant reduction in the grub population for at least 2 to 3 years. This powder is safe to use when children and pets are around.
  • Another environmentally safe method is using nematodes. You may need more than one application to get rid of the grubs for good.
  • You can destroy the eggs by allowing your lawn to dry out significantly between watering. Many chemical insecticides in form of sprays and granules are effective in controlling the grubs.

Controlling the Adult Japanese Beetles

  • The best way to get rid of the beetles is taking a bucket of soapy water through your garden early at day break. The beetles are slow and sluggish during this time, and you can simply pick them and drown them in soapy water! This technique works well when they are less active and in number.
  • You can prepare homemade trap. There are two types of traps, one that uses female beetles pheromones and the other that uses the smell of its favorite food. You can place these traps downwind and far away from the plants you want to protect. Be extra careful when using these traps as they may attract more beetles than you can trap.
  • Try placing nets on your ornamental as well as vegetables gardens during peak beetle infestation season. Beetles tend to consume plants from the top and move downwards towards the roots. Thus, nets placed on the top of the plants will deter them from attacking your plant. The beetle will instead move on to other source of food.
  • Planting interplant Mirabilis, larkspur, white geraniums, red buckeyes and dwarf buckeyes plants is also a good option. The flowers of these plants attract and poison the beetles. The leaves of the Castor bean plant poison them. You should take care that children and pets are kept away from these poisonous plants.
  • Spray plants with neem oil to keep them away. Neem oil is a natural insect repellent.
  • Another natural repellent is using a spray made from garlic. Or you can try growing garlic around your flower and vegetable patch. These beetles tend to avoid garlic just like as a vampire. So, make sure you plant single garlic cloves in a line around the garden areas you want to avoid these beetles.

Homemade Japanese Beetle Trap

Repellent Recipe # 1

Ingredients
  • 1 cup water
  • ½ cup sugar
  • 1 mashed banana
  • 1 packet yeast

Method of Preparation:

Dissolve sugar and yeast in the water. Add mashed banana to the sugar-water. Mix well. Pour the mixture in a gallon milk jug. With the top off, place the jug in an area where they gather. The fermentation and odor of the bait attracts the beetles to the mixture and will compel them to get in but won't let them crawl out.

Repellent Recipe # 2

Ingredients
  • 1½ gallon spray bottle
  • Warm water
  • 3 teaspoon of garlic powder
  • 2 teaspoon of cayenne pepper,
  • ¼ cup of liquid dish soap
  • ¼ cup of vegetable oil

Method of Preparation

Mix the above ingredients in about a gallon of water. Fill it in a spray bottle and spray the liquid over the leaves and plants affected. The beetles don't like garlic and cayenne pepper will make the leaves too hot to eat.
The smell of garlic and cayenne pepper sticks to the leaves with the help of the dish soap and vegetable oil. Thus, the beetles won't be able to feed on the leaves and will have no choice, but to leave your garden.

Repellent Recipe # 3

Ingredients
  • 1½ gallon spray bottle
  • 1 gallon warm water
  • 2 tablespoons Castor oil
  • ¼ cup of liquid dish soap

Method of Preparation

Mix the above ingredients in a spray bottle and spray on the top and under the leaves of the plants. This liquid concoction will definitely kill the troublesome insects. But, remember, this concoction is deadly enough to affect other harmless and useful bugs as well.
It has been found that fir, arborvitae, spruce, pine hemlock and rhododendron are not attacked by these beetles. Lilac, magnolia, holly, euonymus, dogwood, boxwood, carnations, bleeding heart and red maple are also found to be resistant to Japanese beetles.
Flowers that are resistant to them are ageratum, snapdragon, columbine, begonia and yucca. Some vegetables like onions, rutabaga, cauliflower, red pepper, lettuce, tomato and parsley are also found to be resistant to these pests.