The Japanese beetle has been a problem in gardens since the early 1900’s when it first entered the USA through New Jersey. Since that time it has found very few natural enemys which has allowed it to grow freely in the eastern united states .. those states east of the Mississippi River.. however western states like Arkansas and Iowa have seen populations causing problems.
Both the Grubs or larval stage and Adults are a pest that can be destructive to plants.
Grubs will eat the roots of plants as they grow to become adults and then Adults will feed on such a large variety of plants that there are really no plants not in danger.
The adults love to feed on vegetables and especially grapes and tomato plants. They will eat the green part of the leaf which will kill the plant since it can not get proper sunlight to grow. They also like rose plants and can destroy a garden of flowers in just a few days.
While the female feeds on plants every few days they will dig into the ground and lay eggs. The eggs grow to larva and the grubs feed on roots.
Once Japanese Beetles have established themselves in your garden it can be very difficult to get rid of them.
Protecting Your Garden from Japanese Beetles
Unfortunately the beetles that you find in your garden may have traveled up to a few hundred yards from their home so it can be difficult to kill the larva and expect to rid the adults.
To inspect your lawn for grub infestation you dig a 1 foot square patch of grass just below its roots pealing it back as if you were harvesting sod.
Look for any grubs and count them. If you find more then 10 grubs in your 1 foot by 1 foot test area your lawn should be treated for grubs immediately. If you find fewer grubs then you may want to treat before you have a problem. If you only find a couple it is not yet a problem.
Diazinon is a good grub killer and it will also work well to control other pests in your garden but it should not be used around your vegetables. It comes in a granular form that you apply with a garden spreader. Make sure that you wear eye protection and a dust mask or chemical mask when applying it. Read the directions for precautions and use.
Adults should be sprayed directly. This can be difficult as it requires you to continuously manage the adult beetles but because they are normally slow a garden sprayer should be useful in applying pesticide. Ask your local retailer which products work best for adult beetles. Products with Acephate, Carbaryl, Malathion, Methoxychlor, Rotenone may be useful. Always take precautions and read the directions when using any pesticide in your yard.
Final Note
Pesticides can be very dangerous and if you find that you become sick after using them you have probably not protected yourself correctly.
Some pesticides will stay in your body for an extended period. Others will be eliminated within days.
If you find you are not feeling good after using pesticides you may want to visit a doctor but at the very least you should not use the product again until you understand why you got sick.
Many people ignore the warnings of feeling achy, tired or sick and just think it was because of too much work in the garden.. but it can be low level poisoning.