Rose Midge Control

Updated 2011


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Time to stop fertilizing, but if you spray for disease, keep that up until late Nov.

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Rose Midge Control Update



Control of midge remains the same as before, with perhaps a warning: If you have detected midge in your rose garden, do not assume that they have been conquered after an application of Merit and no new midge sighted in several weeks.  All the folks I have talked with on the subject seem to agree- you may have had infestation in the past but did not recognize the subtle symptoms; OR you now have a Problem with Midge that is new.  In both cases, the solution is not quick and easy (as may be the case with aphids, for example).  And the midge do not have a definite season (like Japanese beetles are seldom seen before July 4 in CT, and are usually not a problem by September).  Be sure to apply anti-midge granules or soil spray at monthly intervals in the summer- for the entire years in which they have been detected.  Maybe you will be lucky the next year, but most seem to find that once you have incurred an infestation you are likely to have recurrence.  Like most insect pest arracks: don't treat until you have the problem.  But once you Have Midge, you should be proactive thereafter (including the following year).


From Don Myers, past National CR Chairman:

My recommendations for midge remain the same as they have for the last 5 years.

3 applications of a product containing imadacloprid (Merit) at monthly intervals to the soil surrounding roses starting at bud break. Multiple applications are necessary. One is not sufficient. Foliar applications are much less effective, but may be used to supplement the soil applications. Merit is a fully supported and registered pesticide and not on the way out.

Don Myers
Aug 2008- an excellent set of articles updating Midge:
Editors note: Most all effective controls reference Bayer products (in 2007, 2008). Diazinon (pre-Bayer) was taken off the market. Orthene/Isotox may be effective- for the short period the larva are in the bud. Overwhelming reports indicate that very frequent applications of these insecticides (every 10 days, per label) is vital for control. Early May (in CT) applications of Merit-containing grub-type granules appear to be effective for allowing a Spring (June in CT) bloom, but not sufficient for late in the season.

August 2007, email from Dave Berg. Used with permission:

To: Don Julien
Hi Don
I I found your article in the ARS magazine on "Critters" very interesting particularly the paragraph on Rose Midge. I guess I qualify as a large garden with 75 HT, Fl, and shrubs and the balance (150) minis. I have a midge problem big time. I would guess I lost 1/3 to 1/2 of my spring bloom but have to admit I didn't do anything to prevent the damage in the spring. I'm still having the problem and have done quite a bit of research and am trying to put what I have found to practice now hoping for a decent fall bloom for a show. My sources for info were the Ct AG. STATION in Windsor, The UNIV OF CT. COOPERATIVE EXTENSION staff in Storrs Ct and Don Myers. The conclusion is the use of Imidacloprid, which I believe is Merit and Cyfluthrin( and I have no idea what this is). These are the two products you mentioned in your article. I found both of these products in two different formulations at Lowe's. The first was a bag of granular( Bayer Advanced Complete Insect Killer for Soil and Turf). Label--Imidacloprid .15% and B- Cyfluthrin .05%. The second was a hose end sprayer ( Bayer Advanced Complete Insect Killer for Soil & Turf) label same as the other. Label-Imidacloprid .72% and Beta Cyfluthrin .36%. I have started to use both but obviously won't know how effective for a month or so. I'm not sure I've given you any info you don't already have but hope it helps.
Dave Berg

The article below was taken from Tom Mayhew’s 2006 Consulting Rosarian Report: May in the Rose Garden. A severe infestation of rose midge will leave you with little or no blooms in your garden, so prevention is the key to this problem.
Rose Midge: May is the time of the year that you might start seeing rose midge damage to the roses. The rose midge tiny larvae destroy the tips of new growth and developing rosebuds, leaving the rose with burned and shriveled growth. This results in a “blind shoot” and no flower. The tiny, hard to see, mosquito-like rose midge has a 10-14 day life cycle, part of which is spent in a cocoon in the ground under the rose bushes. A soil treatment should be put down around and under the rose bushes sometime in April or early May (Editor's note: those dates are best for Penn-Jersey District, for CT and New England May or early June are more appropriate dates), and then possibly again in July or August, especially if you see evidence of rose midge activity. Among the possible treatments, two products that actually list rose midge on the foldout label are Bayer Advanced Garden Rose & Flower Insect Killer (liquid) (claims: lasts 30 days, covers 500 rose bushes) and Bayer Advanced Lawn Complete Insect Killer for Soil and Turf (liquid) (claims: 3-month protection, covers 5000 square feet). Both come in a ready-to-spray container with a hose end connection (no mixing). Either of these two Bayer Advanced liquid products could be used as a soil drench for a rose midge treatment. Both contain Merit’s active ingredient imidacloprid, a systemic compound developed by Bayer. Bayer also makes a granular Complete Insect Killer for Soil and Turf, which contains the same active ingredients (imidacloprid and beta-cyfluthrin) as the liquid version of the product with the same name, however, Rose Midge is not specifically listed on the label for this easy to use granular product.
Used with Tom Mayhew's permission.


Earlier information, compiled:

A less frequently recognized problem than aphids and Japanese Beetles, midge can be a devastating problem if the garden is attacked. You have fine foliage, but a black nub at the end of the stem instead of the bloom (which will never come). This blind shoot is the symptom. You will not see the midge culprit.
Rose Midge- Identify the Symptoms and Treatment (Preventive Measures)
Funny thing about rose midge. You can grow roses for many years and never see it, and then suddenly it appears. I'm sure it comes in to the garden in the soil from potted roses. But once you have it, it will be a problem every season thereafter. It's no big deal, really, you just have to remember to apply some Merit Granules, or a grub preventer from your garden center, on the soil of the rosebeds twice a season-- once in early spring, and once in mid-July.

Rose midge is a teeny-tiny flying insect that you never see, and that spends its life in the soil of rosebeds--except the day it flies up to the top of the plant and devours the teeny-tiny developing rosebuds. If you don't know what to look for, the rose stem will continue to grow normally-- except it won't have a bud (and consequently, a flower) at the top. Many people call these flowerless stems "blind shoots," but a rose plant will virtually never throw up a flowerless cane of its own volition. So it's not really a blind shoot, but one that's been damaged by rose midge.

Rose midge damage, once spotted, is easily pruned off the plant, and a new stem will start growing to replace the damaged one. Not tragic, but pruning will delay the date that you expected to see a flower on the plant. Again, it's no big deal unless you're an exhibitor who expects to have flowers in bloom on rose show day.

There are a couple of ways to spot rose midge damage early on. If you're in the garden every day, you may notice tiny black (and dead) sepals at the top of a new stem, surrounding an empty space where the bud should be. These dead sepals fall off the plant quickly, so you may not see them at all-- just no bud. Midge often strikes roses very early in the spring when the new canes may be only a couple of inches tall. You might notice that the inside surfaces of the topmost tiny leaf petioles are spread wide open and face almost straight upward, rather than being tightly curled inward, facing the stem. Wow, that's hard to explain! And I don't know if I can make it clearer, except that normally, the points of the leaves would point upward, and with midge damage, the leaf tips point downward. Like the view of an umbrella from above.

Anyway, be on the lookout for rose midge damage, or if you've had midge in previous years, treat the soil now!
Ann Hooper
Primary Products

The Consulting Rosarian Manual, excerpted, says:
...Adult is minute (<1/8" long) and lays eggs on succulent new growth and under sepals of flower buds. In two days they hatch and feed on the new growth causing it to turn brown and die, preventing development of a bud.
Symptoms: The telltale sign, a tiny crisp, burnt-like bit of foliage at the tip of new growth, is often the first sign of rose midge.
Control: Weekly examination, early year soil applications of insecticide, and treat roses with insecticidal as recommended on the product label for rose midge.
Several of us have experienced this problem this year. And since the named soil insecticide product in the CR Manual is no longer readily available and will be off the market Dec. 2004, the recent research and investigations of our members is both timely and particularly useful.

From Dave Berg email:
Hi Everyone,
I have developed a serious case of midge and I thought some of you might be interested in what I have found out in the last few days.
I have a serious case in one section of our HT section. Beautiful 4-6' healthy plants with nice long new stems and all have tell-tale sign of midge at the terminal end of each cane. Doubt if we will get a fall bloom.
Started in investigation on the web. Searched for rose midge and found a number of sites that described the problem and life cycle but no real good solutions. It is worth looking at a couple of the sites however.
Sent a email to Robbie Tucker at Rosemania asking if he had any product that would control. His reply was that some people are using a drench of Merit which he carries as a 2 oz bottle of WP at $59.00. As you may know Merit is the product that some people are using in place of Oftenol for the control of grubs in lawns. (Dave C. note: Oftenol will be off the market soon too)
Talked to Tom Rathier from the CT Ag Station in Windsor and who talked at our Yankee Dist. Convention last spring. He said he had no real experience on Midge but looked in his computer and suggested applying a drench and/or spray using any product I could find that contained imidacloprid (which is Merit) and cyfluthrin (have no idea what that is)
Sent an email to Don Myers at Bayer (who also talked at the convention) asking him if Bayer had a product to control Midge. Answer--yes. They have a hose end container that contains both products and he said he has heard good reports. Went to Lowes and found it. It is called Bayer Advanced Garden Rose and Flower Insect Killer in an hose end container. A 32 oz bottle cost $9.87. Don said to spray under the plants, under the plants and surrounding area. I did notice at Lowes that they had a bag of granular with the same ingredients but don't know the cost.
I plan to spray with this tomorrow and hope for the best.

From Dave Gade
I sympathize with you - I've had serious bouts with midge over the years. In the past, I used Diazinon about every two weeks. When I heard it was going off the market, I was steered to the same product Don recommended. I used it last year with great success.
Prune off the infected shoots and discard. Spray with Bayer Garden Rose and Flower Insect Killer - spray bush and ground. You will have instant success. And I believe you'll get fall bloom. In severe cases, spray again in 10 - 13 days because they cycle quickly. I would even recommend you do it next spring in mid to late May. Good luck!

From Dave Candler:
I have a 'midge problem' for the first time this year. Noticed mid-August. Sprayed foliage with Merit and applied a soil drench of Merit® (wetable powder). Too early to know results. I also did some research on the web. A useful article I found was by Bob Martin, Jr. (also a speaker at our spring convention, and author of the outstanding book Showing Good Roses). His article highly touts Merit® for use on THRIPS (does not discuss Midge). Some similarity can be found between the pests, however, and the article is well written.
The article can be found by navigating:
Concerning Thrips and Merit®
Home page, then Expert Advice
then select Insecticide Update (by Robert Martin Jr.).

Some Additional Links to rose midge on the Internet:
(note: articles generally pre-date Merit as a treatment)
(excellent pictures of examples) 
The Bugman on ARS- good article (note: may need ARS Member Login. Copy/paste link if issues)
Univ. of Ill.
Univ. of Minn.





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