Japanese Beetles

I think these beetles are more devastating to the rose industry in the East than anything else. My neighbors refuse to grow roses, not because of blackspot, but because of the beetles. For those that live in beetle free areas, here are some pictures. Please note that it is not just a few roses in my garden that look like these picture, but nearly all of them.



I have been looking high and low for a rose that truly resists Japanese Beetles. Does anyone know of any? I am really hoping there is a rose gene out there that makes a rose unappealing to these beetles. I suspect, however, that this may require genetic engineering. Any thoughts?

Geez what pigs. If one is seen in my county, we are supposed call the extension agents and report it. Well, thats what I remember from the Master Gardener meetings anyhow.

Saw my first one a couple of weeks ago. Wonder how long until I am be-sieged. They have yet to make it in mass to this part of the country but I am sure will be here soon. I guess I could hope that its to dry for them in NE. Not likely I guess. Nasty insects.

SteveJ, if you can, work with your neighbors and/or community to try and keep the beetles to a minimum. You will be glad you did. To give you an example of just how bad they can get, my neighbor has a large Crabapple tree, and when I sprayed it, I would guess around 2,000 beetles fell out of it. The tree was almost completely defoliated. And yet, with that many beetles on that tree, there were still thousands in my yard. They stripped my William Baffin hedge bare within three days (I’m not kidding) and my cherry tree looks terrible. When I mowed the lawn on Saturday, I was getting pegged with beetles. It reminds me of the Biblical stories of locust. Thankfully, this year is not normal, but even on normal years, roses don’t stand a chance.

I guess I should be grateful they are eating my roses and not eating me=). I would take beetles over mosquitos anyday.

I think you can get good control of the beetles with “milky spore disease” Years ago (1960s)I lived in western PA and they came in as a plague. Really destroyed a lot of fine flowers. Then the disease came by and not they are scarce most of the time. My mother never complains that they bother the few rese bushes she still maintains.

That is good to know. I have put down milky spore, but unless my neighbors put it down and their neighbors put it down and their neighbors put it down, etc, I don’t think it will make a difference. I will attempt to talk my neighbors into it.

Here are some more pictures that I found on another site. It looks like my roses. Be warned, you will have nightmares.=)


I think it would be worth the time and effort to breed (or genetically engineer) roses that are unattractive to these beetles.

For those interested, Coral Flower Carpet and The Fairy are the only two roses in my garden that seem quite resistant to these bugs. Even their flowers are untouched. I thought it was because of their lack of fragrance, but my equally non-fragrant William Baffins, Carefree Delights and Knockouts are devoured. The beetles actually fly right over my Coral Flower Carpet to get to Knockout and my other roses. Maybe there is something there. Maybe not.

Illusion, a red Kordesii climber

I have grown plants of Illusion since the early 70’s at two different locations in northern Ohio. I have found it to have beautiful red, very double, and relatively large flowers. It is also a continual bloomer, blackspot- and mildew-free (without spraying), and relatively hardy (here in a normal zone 5b winter, -10 to -15 degrees F, only the tips show any winter injury). A very important point, in northern Ohio, is that the Japanese Beetles ignore it! Illusion occupies the premier location in my front yard - it surrounds the lamp post.

In Modern Roses 10 Illusion is described as a Kordesii (the second parent has never been disclosed) shrub that was hybridized in 1961 by Kordes. “Flowers blood-red to cinnabar, dbl., large blooms in large clusters; fragrant; foliage leathery, glossy, light green; vigorous growth.” In Wilhelm Kordes book, Roses, Reinhold Publishing Corporation, page 195 (1964) Illusion is described as having flowers that are large, full, well-formed with wild rose fragrance. The blooms are about 3 inches across and appear in clusters of up to 8 individual florets. The time of flowering is early, and the habit of growth is upright with good branching. He recommends it as a pillar, hedge, and/or specimen shrub. It can reach a height of 10 feet. It is free flowering and resistant to disease. In the 1965 Rose Annual of the British National Rose Society, Wilhelm Kordes wrote an article titled “The History of Rosa kordesii, Wulff”. In the article he states: “We brought out Illusion in 1961. It is a really rich deep blood red, very free flowering and an upright grower, with the scent of the dog rose.” Roy Genders in his book, The Rose, A Complete Handbook, Bobbs-Merrill Company publisher, page 440, (1965) stated the following about Illusion: “A most arresting climber with its huge trusses of fragrant flowers of exotic cinnabar-red which are borne all along the stems to a height of 8 - 9 ft.”

The University of Minnesota Agricultural Experiment Station published, in 1995, a 92-page report Roses for the North (item number ESMR-6594-SKID, cost $11.95 plus $3.50 shipping and handling, Minnesota Extension Service, 415 Coffey Hall, 1420 Eckles Ave, Saint Paul, MN 55108-6068). Illusion was one of the roses evaluated. For bloom pattern Illusion is reported to have heavy June bloom, slight July rebloom, and moderate August/September rebloom. For comparison this is the same bloom pattern reported for Dortmund, Henry Kelsey, and William Baffin. For winter injury Illusion was found to have dieback to the snow line, to the ground, and to the snow line for the winters of 1988-89, 1989-90, and 1990-91 respectively (remember the tests were done in zone 4a where the minimum winter temperatures are in the range of - 25 and -30 degrees F). This was the same as reported for Dortmund, Alchymist, Bonica, and for the hybrid rugosa, Hunter. In the section on diseases, Illusion did not exhibit any blackspot, powdery mildew, leaf spots, or rust during the two years of the study. Unfortunately in the section on insect observations, none of the Kordesiis were listed.

Illusion does set hips. The seeds are relatively easy to germinate. I am very impressed with the seedlings that I have grown. All of the flowers have been double, and all but one (a pink) have been a rich red. Since the oldest seedlings are only two years old, it is too soon to know what type (climber, shrub, etc.) they will be. I am now trying to cross Illusion and William Baffin with the hope of obtaining a climber with the hardiness of William Baffin and the flower of Illusion. I would suggest that crosses of Illusion with red hybrid teas be made in an attempt to increase the fragrance and/or hardiness and/or disease resistance and/or the insect resistance of the red hybrid tea class. It is not often one can hope for four possible improvements from one cross!

I purchased both of my plants from Pickering Nurseries, 670 Kingston Road, Pickering, Ontario L1V 1A6 (they do ship to the USA).

Thanks Henry! I tried to get Illusion this year from Hortico, but they did not have any available. I am glad to hear the beetles ignore it, especially since it has some fragrance and larger flowers. I would love to see how Illusion fares in my little piece of Japanese Beetle heaven. I will try anything at this point. Have you noticed any other roses that the beetles find less tasty?

I do wonder if there is some resistance coming from R. Wichuriana. As I mentioned before, my Fairy goes completely untouched, even when in full bloom. That is quite remarkable. By the look of the leaves, I am also assuming Coral Flower Carpet is of Wichuriana decent. In three years I have seen maybe 2 beetles on that rose.

Can anyone else think of any other roses that are resistant? I am going to create roses that are beetle-free, by gum!!! =) As I said before, Japanese Beetles are the biggest problem in my area. Blackspot is also a major problem, but it can be controlled with a weekly or bi-weekly spraying; beetles cannot.

All the Flower Carpets come from R. wich descent for sure. I think, if I remember without looking them up, theyre bred from a Kordes groundcover using R. wich and The Fairy.

The thing that I notices with the majority of these roses is that the blooms smell like really bad plastic. Its hard to descrive but they sure dont smell “rosy” at all. What do Japanese Beetles look for?

Title: Floral characteristics affect susceptibility of hybrid tea roses, Rosa x hybrida, to Japanese beetles (Coleoptera: Scarabaeidae).

Authors: Held David W; Potter Daniel A

Aothors affiliation: Department of Entomology, University of Kentucky, Lexington, KY 40546-0091, USA.

Published in: Journal of economic entomology, volumn 97, pages 353-360, (2004 Apr).

Abstract: “The Japanese beetle, Popillia japonica Newman, feeds on the flowers and foliage of roses. Rosa x hybrida. Beetles attracted to roses land almost exclusively on the flowers. This study evaluated characteristics of rose flowers including color, size, petal count and fragrance, as well as height of plants and blooms within plant as factors in attractiveness to Japanese beetles. Artificial flowers that had been painted to match the spectral reflectance of real blooms were attached to potted nonflowering rose plants in the field and the number of beetles that landed on each model was recorded. More beetles landed on the yellow- and white-colored flower models than on the five other bloom colors that were tested. Large (15 cm diameter) yellow flower models attracted more beetles than did smaller (8 cm diameter) yellow models. There was no difference in beetle response to yellow flower models of the same size that differed in bloom complexity (i.e., number of petals). Experiments in which blooming rose plants were elevated above controls, or in which flower models were placed at different heights within plant canopies, failed to support the hypothesis that height per se accounts for beetles’ attraction to flowers over leaves. Attractiveness of selected rose cultivars that varied in fragrance and flower color also was evaluated in the field. Yellow-flowered cultivars were more susceptible than those with red flowers, regardless of fragrance intensity as rated by breeders. Growing cultivars of roses that have relatively dark and small-sized blooms may have some benefit in reducing Japanese beetles’ attraction to roses.”

Oh! Ultraviolet then maybe?

Title: Potential for habituation to a neem-based feeding deterrent in Japanese beetles, Popillia japonica

Authors: Held, D. W.; Eaton, T.; Potter, D. A.

Authors affiliation: Department of Entomology, University of Kentucky, S-225 Agric. Science Bldg. North, Lexington, KY, 40546-0091, USA.

Published in: Entomologia Experimentalis et Applicata 101(1) October 2001. pages 25-32.

Abstract: “We tested the potential for the Japanese beetle, Popillia japonica Newman, to habituate to a neem-based feeding deterrent applied to foliage of linden, Tilia cordata L., a preferred host for the adults. Female beetles’ consumption of control foliage versus foliage treated with either a low or high rate of neem insecticide, corresponding to 9 or 39 pm azadirachtin, respectively, was tested in a series of 4-h choice or no-choice tests over four successive days. In another experiment, females were conditioned for 22 h with either control foliage, leaves treated with the low rate, or a mixture of both treated and untreated leaves. Deterrence of either the low or high rate of neem to these beetles was then evaluated in choice tests with control foliage, as before. In choice tests, mean consumption of control foliage was always greater than for treated foliage, regardless of rate. There was, however, proportionately more feeding on foliage treated with the high rate upon successive exposures. In no-choice tests, beetles initially deterred by the low rate were not significantly deterred by that rate by the third and fourth days of the experiment. Finally, beetles conditioned by exposure to leaves treated with the low rate were not deterred by that rate in a subsequent choice test, although they were deterred by the higher rate. Despite these trends, we suggest that Japanese beetles’ polyphagy and mobility probably would reduce the likelihood for habituation to neem-based feeding deterrents in the field.”

Authors: Witt, J. Dale; Warren, Stuart L.; Ranney, Thomas G.; Baker, James R.

Authors affiliation: Department of Horticultural Science, North Carolina State University, Raleigh, NC, 27695-7609, USA.

Title" Biorational and conventional plant protectants reduce feeding by adult Japanese beetles

Published in: Journal of Environmental Horticulture 17(4) December 1999. pages 203-206.

Abstract: “Nine commercial plant protectants were tested for efficacy against feeding by adult Japanese beetles (Popillia japonica Newman). Treatments included an endotoxin from a bacterium (Bacillus thuringiensis (Berl.) var. san diego); microencapsulated pyrethrum extracted from pyrethrum (Tanacetum cinnerariifolium (Trev.) Schultz-Bip.), two extracts from neem (Azadirachta indica A. Juss); an extract from cayenne pepper (Capsicum annuum L. var. annuum Longum Group); an extract from garlic (Allium sativum L.); rotenone extracted from galedupa (Derris trifoliata Lour.) and barbasco (Lonchocarpus sericeus (Poiret) Kunth) or timbo (L. nicou Aublet D.C.); carbaryl (1-napthyl methylcarbamate); and the pyrethroid, fenpropathrin. Experimental plots were located at the Horticulture Field Laboratory (HFL), Raleigh, and the Mountain Horticultural Crops Research and Extension Center (MHCREC), Fletcher, NC. Himalayan birches (Betula utilis var. jacquemontii (Spach) Winkl.) were used as host plants. Treatments were applied twice, 2 weeks apart. Five weeks after initial application, trees treated with fenpropathrin averaged 2% defoliation vs. 40% defoliation for the control trees at HFL; and 3% defoliation vs. 100% defoliation for the control trees at MHCREC. Rotenone treatments averaged 10% defoliation at HFL and 92% defoliation at MHCREC. The following treatments were not significantly different from the control at week 5 at either location: garlic extract, neem extracts, cayenne pepper extract, microencapsulated pyrethrum, encapsulated bacterial endotoxin, and carbaryl.”

So–one study found that neem extract seemed to have some effect, but another study found that it didn’t?

A quick stock market tip:

Invest in Japanese beetles, not in the stock of those who sell neem extract to deter Japanese beetle defoliation.

Peter, the one study did 2 week intervals between spraying. In other threads it appears that neem gives about 2 days protection. I tried extending this by mixing Neem with Wilt Pruf. I thought that it helped, but maybe Wilt Pruf by itself would work as possibly the beetles did not recognize a Wilt Pruf covered leaf as food. I also tried mixing commercial garden garlic concentrate with Wilt Pruf. I thought that it helped also.

It sounds like a lot of trouble for a questionable to negligible benefit.

I have (and have had) a lot trouble with deer browsing my roses. I’ve read all the advice and tried a number of remedies (including Deer-Proof (-Pruf?) and Hinder, mesh bags of hair fresh from the barber shop, bars of soap, soap and egg spray). I’ve come to the conclusion that the only effective remedies are physical or electrical fences. However, thinking about the bags of hair and the bars of soap hanging among the roses, I’ve come up with what may be a hair-brained solution: to hang deer among the roses to show what will happen to unlicensed browsers.

Moving on to the matter at hand–

Has anyone tried hanging Japanese beetles among the roses to discourage feeding by other Japanese beetles? This could be done either by putting large numbers of dead beetles in bags, or by harnessing living beetles to threads to send either auditory or pheromonal warnings to other beetles. Deterrence probably would not be any more effective than detergents, but it’s hard to say until it’s tried.

Rose society articles about Neem


Link: www.mgs.md.gov/mdrose/rfaq5bug.html

Thanks for the information Henry. For the most part, I agree with the study regarding color and fragrance.

My Sunsprites, Playboys and Double Delights are the favorite beetle snacks in my yard. Despite a lack of fragrance, Carefree Sunshine is just as susceptible. Pretty Lady (which is generally white for me), another rose with little fragrance, is also quite susceptible to beetles.

The part that does not fit the study are my Mr Lincoln and Knockout roses. While not quite as susceptible as the roses listed above, they always have beetles on them.

The one very fragrant rose that seems to be less appealing to the beetles is Fragrant Cloud. If my Sunsprites, Pretty Ladies, or Mr Lincolns are in bloom, they will not touch my row of Fragrant Clouds. I also noticed this at a public garden. A row of Fragrant Clouds was untouched, while a neighboring row of Livin Easy was smothered in beetles. The same went for a row of Dolly Parton (a child of Fragrant Cloud) that was virtually untouched while a neighboring row of French Perfume was covered in beetles.

With that said, Fragrant Cloud IS NOT immune, just less susceptible. If other, more desirable roses are not blooming, the beetles attack my Fragrant Clouds with a vengeance.