August 2018- Winning The Battle Against Japanese Beetles

At one time or another, every gardener has experienced the frustration of having damage caused by Japanese Beetles. With its shiny copper color and brilliant emerald green head, these damaging insects are anything but a welcome site. There are no guaranteed ways to eliminate these insects, but you can take steps to minimize their presence.


Japanese beetles made their first known appearance in the United States in New Jersey in 1916. It is widely assumed that their actual origin in the United States was a result of beetles hiding in a shipment of Japanese Iris. With no natural predators, perfect weather conditions and a limitless supply of irrigated turf, the beetle population exploded by the 1920’s.



Japanese Beetles spend most of their life cycle underground. First as an egg, then a larvae, then as a pupa before emerging as an adult beetle. Reaching up to an ½ inch in size and a life cycle of 35-50 days, they may be small but can wreak havoc in their short time above ground. Rose buds, leafs and fruit producing trees are a favorite target of beetles but they can be found on just about any leafy plant or flower. It is uncommon to spot a single beetle feeding on your plants. That is because mature beetles emit a pheromone when they’re eating. The females will fly to an area of turf grass and lay an average of three eggs just a few inches below the surface. They repeat this process every twenty-four hours. Once the eggs are laid and hatch, the next life-cycle begins.



Not only do beetles cause visible damage on plants, your grass can also be the victim of beetles during their larvae stage. Larvae, also known as grubs, can be found chewing on the roots of your grass just a few inches below the surface. This typically results in brown spots throughout your lawn as well as an increase in mole population. Moles consider grubs a delicacy.


Prevention Goes A Long Way

By applying grub control to your lawn you can disrupt the life cycle of beetles. Also by minimizing how often you water your lawn during the dry spells can help since females seek wet turf to lay their eggs. You can also apply a milky spore dust to your lawn. This is an ingested bacteria that only damages Japanese beetle grubs and larvae. It contains a bacteria that will kill grubs but is safe to use around people and animals.



Japanese Beetle traps are also a great, natural way to control beetles. They release a pheromone that beetles find irresistible, therefore drawing the beetles to the trap. It is recommended that the trap be placed away from tender vegetation as it can attract beetles from a large area. Be prepared to change the trap’s bag frequently during beetle’s feeding season. You can also head outdoors with a pair of gardener gloves and a bucket of water. Simply knock off any beetles you see into the bucket and cover for a few days. If using chemical applications to control beetles, be sure to thoroughly read the directions before use.