This Month's How-to:
Know your Pests: Japanese Beetles

Among all the pests that plague our area, perhaps the most despised is the Japanese Beetle.  During their larval stage they eat our lawns, and, upon maturity they ravage our shrubs.  Yet these invasive critters have adapted to their new environment with a remarkable ease.

The life cycle of the Japanese Beetle (Popillia japonica ) is quite remarkable.  In early spring, the grubs living deep in the soil begin to make their way toward the surface.  It is during this time that they take advantage of the root system of the grass plant to get their last burst of energy before they pupate and enter their adult forms. Then on a warm, summer day, just after a rain has softened the earth they emerge from the ground and take flight.  Over the course of the next eight weeks they migrate from plant to plant, led by their powerful sense of smell.  Certain shrubs have aromas that are irresistible to Japanese Beetles, but barely noticeable to humans.  This explains why swarms always seem to descend on the same plants each year.  In late afternoon, female Japanese Beetles drop to the ground in search of a soft place in which they can burrow into the soil to lay their eggs.  Generally, this takes place in wet areas.  These eggs then hatch before the ground freezes in winter, and the larvae bury deep into the ground and enter dormancy, only to begin the process the next spring.

It is difficult, but not impossible to eliminate Japanese Beetles.  They can be temporarily removed by spraying them with the hose (this will cause them to flip over and drop to the ground) or spraying topical products, many of which can be washed off in the rain.  An additional repelling tactic that we are often asked are the popular green lure traps.  Just in case you are not familiar with lure traps, they are the green and yellow bags that you see hanging in peoples yards every summer.  These products are so backwards; they should actually be called “Bait Bags.” As a result of the powerful pheromones they contain, the number of beetles on a property actually increases when these beetle collectors are hung up. The only way they will have any positive effect is if you give one to each of your neighbors to draw the bugs away from your own yard.

Let us be clear:  LURE TRAPS DO NOT WORK.

The key to eliminating Japanese Beetles is to interrupt their progress at each stage of their growth cycle.  Chris Orser Landscaping, Inc. uses a two-step approach, first attacking them while they are still in their larval stage by applying grub control, such as Merit, between April and August. Any grubs that survive to become beetles can be eliminated using a special commercial spray called Sevin once the season has begun. Sevin does an excellent job halting an infestation of Popillia japonica because it is a systemic pesticide.  These special chemicals are sprayed onto affected plants, quickly absorbed by the leaf, and ultimately passed onto the feeding beetle. This internalized technique is essential because of the beetle’s tough shell.  A

long term solution can be found in the propagation of Milky Spore nematodes throughout your lawn.  These microscopic worms take several years to achieve maximum efficiency, but once they do, turf areas become uninhabitable by most larvae.  If you want to  get rid of your grubs or butcher your beetles, give Chris Orser Landscaping a call.