Field and Farm

Posted 5/27/18

By DANNY L. CAINWalker County Extension Agent Only few days left until dreaded "June Bugs" returnWith Memorial Day weekend here and given that we are only a few days away from June, that usually …

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Field and Farm



Walker County Extension Agent


Only few days left until dreaded "June Bugs" return

With Memorial Day weekend here and given that we are only a few days away from June, that usually means the “return” of at least one unwelcomed pest in home landscapes, orchards, and gardens (as if ticks, fleas, and mosquitos weren’t enough to deal with).  It is around the first week or so of June that we usually see the beginning of the emergence of those dreaded “baby June bugs” that eat all of our plants down.  Actually, they are not June bugs at all but rather Japanese beetles.

Japanese beetles are about ½ inch long and are metallic green in color with a very noticeable pair of bronze colored wing covers.  They have five tufts of white hairs that project out from under their wing covers on each side as well as a sixth pair of white hairs at the tip of their abdomen.  The white tufts of hair appear as small white dots when viewed from above.  In all actuality they are fairly attractive insects (attractive as far as bugs go that is) and they actually do resemble miniature June bugs as many people describe them to me.  Their attractive appearance; however, is about the only good thing that I can say about them.  Japanese beetles are a highly destructive insect in both their larva (grub) stage as well as the adults that are out in tremendous numbers right now.  In fact Japanese beetles have been known to feed on more than three hundred different plants.  Among their favorites are anything in the rose family, crape myrtles, fruit trees, and Japanese maple just to name a few.

Japanese beetles usually begin to emerge from the soil by late May or early June with late June being the peak time for emergence in our area.  This emergence pattern will generally taper off in July but we may have encounters with emerging Japanese beetles all the way through fall of the year. Once they have emerged, the beetles immediately begin to feed on your landscape and garden plants, and to make matters worse they release a pheromone scent that attracts other Japanese beetles. 

Did you ever wonder how there got to be so many of them?  Each and every female Japanese beetle can lay between 40 and 60 eggs during her lifetime.  Most of the eggs are laid by mid to late July.  The eggs hatch in one to two weeks and the larvae then overwinters in the soil as a grub.

Control of Japanese beetles is far from easy, as many of you have discovered.  This is a result of their very aggressive feeding habit, which results in the total skeletonized appearance of the damaged foliage. as well as the tremendous number of beetles out there.  Even as I prepare to mention method one, I can already feel your frustration.  By noticing when the first adults arrive on your favorite shrub or bush, you can hand pick them off and destroy them before they have a chance to cause damage and release the pheromone that will soon lead Japanese beetles to your shrubbery by the hundreds.  They can easily be killed by dropping them into a container of soapy water. 

Believe it or not Japanese beetles will not eat everything that grows.  Among the plants that Japanese beetles do not particularly care for are begonias, boxwoods, forsythia, hollies, hydrangeas, junipers, and pines. 

They also cause little or no damage to dusty miller, euonymus, magnolia, or caladiums.  They will cause some damage to oak trees but usually will attack other plants first.  You can reduce the amount of Japanese beetle damage by replacing some plants in your landscape with plants that do not attract them.

Adult Japanese beetles can also be killed with careful application of chemical insecticides.  There are several such products that are labeled for use on most home ornamentals including carbaryl (Sevin and other similar products), acephate (Orthene and similar products), cyfluthrin (Bayer Lawn and Garden Insect Control and other products) and permethrin (sold in a variety of products).  Products containing imidacloprid and bifenthrin also work against Japanese Beetles.  Make sure that the product you select is labeled for use on the plants you will be spraying and be sure to carefully follow the labeled directions on the container.

During heavy adult emergence plants will need to be sprayed every few days.  Many homeowners become discourage and think that the insecticide that they selected is not working.  Actually it is working in most cases but the Japanese beetles emerge so fast and in such large numbers that they are just overwhelming.

There are also Japanese beetle traps available.  Don’t fall into the trap trap.  In most home landscapes, using one or two traps may even do more harm than good.  Remember the traps use a pheromone to attract Japanese Beetles.  While a lot of Japanese beetles will fall into the trap…many will not.  The ones that do not will release pheromone and attract even more beetles into your front yard.  I once got so frustrated with Japanese beetles that I hid a couple of the traps in my next door neighbors yard in hopes of attracting them from my yard over into his.  The traps work good to monitor for beetle emergence but are not that effective as a stand alone control method…. And besides, my neighbor is still mad at me because his roses got eaten up.

One fortunate trend that I have been seeing over the past couple years is that our seasonal outbreak of Japanese beetles doesn’t seem to be as bad as in year’s past.  I think there are several reasons for this including our weather patterns which have given us unusually dry weather in late spring and early summer and also the fact that some of the natural predatory pests of Japanese beetles may be catching up with them.  In any event, lets hope that this year continues the trend of lower Japanese populations as well.