michaelg, is it possible that your use of Round-Up (on your RRD infected bushes last summer) is the cause of at least some of what you are now seeing? (i.e. are some of these "infections" near where you were painting the stubs?)

Quote from last summer:

"Posted by michaelg z6B NC Mts (My Page) on Sun, Jul 1, 12 at 11:14

If you are not up to digging RRD roses right away, cut down the canes in sections and bag them to contain the vector mites. Paint the fresh-cut stubs with full-strength Roundup. Dig at your leisure over a few weeks. "

http://forums2.gardenweb.com/forums/load/roses/msg0602270315611.html
--------------------------------------

Thank you, Michaelg, for alerting folks about removing the plant completely for RRD.

I read the research papers brought up by Henry Kuska. I respect his views ... He's a chemistry professor when I was still in my diaper. I research some more on my own (I took microbiology in college).

One factor that haven't been considered is the use of high-nitrogen fertilizer which attracts pests like aphids and mites. Here's a quote from an abstract below: "According to the available data, if the nitrogen concentration of the leaves of the fruit trees is high (1.8 - 2.6%) the egg production of the spider mites increase."

Virginia Co. Extension stated, "RRD is lethal to the wild multiflora rose, and it is potentially lethal to many ornamental rose species and cultivars. It has long been known that the eriophyid mite, Phyllocoptes fructiphilus, spreads the disease."

I have only 1 rose affected by RRD last July, an own-root rose with multiflora parentage. Since multiflora gets chlorosis in my alkaline clay, I dumped lots of acid fertilizer high in nitrogen on that particular rose. It's a combo of both: multiflora genes, and high nitrogen which attract mites.

I removed that rose completely (plus the surrounding soil). I also sprayed the entire area with Windex (very alkaline, also kills ants). None of my 45+ roses are affected after I removed that one completely.

Here is a link that might be useful: Effect of nitrogen on population of mite and aphid

Someone once mocked me about my defending "my friend" Henry Kuska. Let's make it clear: I don't know Henry, except for taking the time to read the researches he posted .... my minor is in chemistry, hence lies my interest.

Henry Kuska once posted a paper that insecticides have zero effect on reducing insects. I'm a experimenter, and not a theorist. 15 years ago I did that in my last house with acidic clay: I dumped lots of Bayer 3-in-1 insecticides & rose care, plus using blood meal around the fence to keep bunnies away. I had the WORST aphids infestation on my roses, despite the Bayer insecticides. Insects like mites and aphids go bonkers when fed high nitrogen, as in blood meal.

Here's a quote from Mother Jones: "And the casualties aren't just honeybees. Krischik's research shows that beneficial insects (i.e., insects that eat plant-eating insects) like lady bugs and green lacewings are damaged by exposure to imidacloprid-treated plants, in Bayer's insecticide."

In my present house, alkaline clay, I don't use any insecticides and haven't seen aphids for the last 13 years.

No, Henry, that was an "if" clause, and I normally dig the plant as soon as I decide to get rid of it rather than poisoning it first. I only recall brushing the stumps of one plant, a climber. It is true that people need to be careful not to confuse herbicide damage with RRD.

Thank you, Michaelg, for your clarification. I confess that I was a bit annoyed at first when Henry asked me if I used Roundup on the RRD rose that I removed. No, I don't ....

But I got curious about the effect of Roundup on upsetting the eco-system that holds down the surge of mites & aphids. I did some research: herbicides do kill the beneficial predatory insects. If the population of mites is NOT controlled by beneficial insects, and fed plenty with nitrogen and water, they go berserk.

Here's an excerpt on the chemical effect of Glyphosate, or Round-up: "Earthworms and beneficial insects:
Glyphosate has adverse effects on some earthworms; and a number of beneficial insects useful in biological control, particularly predatory mites, carabid beetles, ladybugs, and green lacewings. It can also adversely effect other insects that play an important part in ecological balance such as springtails, wood louse, and field spiders."

The reasons why my present house is 100% freed of aphids for the past 13 years are:

1) I don't use Round-up nor insecticides. I have tons of plants that host beneficial insects such as lacewings, preying mantis, and ladybugs. They are dill, calendula, and yarrow plants.

2) Plants get plenty of nitrogen from my alkaline clay, and I don't need to add chemical nitrogen. I get thrips-infestation in my pots WHEN I watered with NPK 32-10-10 ... but the ones in the ground mulched with horse manure have no thrips. There's lots of weird bugs in the horse manure, they might be predatory to thrips.

3) My only rose with RRD which I removed is NEVER mulched with horse manure. It's an own-root with multiflora genes. I don't give it alkaline horse manure because multiflora prefers acidic soil. Instead I gave it acid fertilizer high in nitrogen.

Here is a link that might be useful: Glyphosate or Round-Up on the ecology

This post was edited by Strawberryhill on Wed, Apr 17, 13 at 12:31

I did more research since I was curious WHY that one rose of mine got RRD although it was healthiest when I first bought it from local Home Depot.

1) Its multiflora parentage has a factor, although it's an own-root. 2) It got the most acid fertilizer high in nitrogen, and I did NOT give it any horse manure.
3) It got the least water among all my roses.

I checked on what's the best pH for mite reproduction, didn't find that, but found that mites flourish best when it's HUMID. I also found info about mites HATING alkalinity. People report success using dishwashing soap, pH 8 to 9, to spray mites.

My soil is alkaline clay, pH 7.7. The horse manure I get ranges from pH 7.4 to 8, depending on the time of the year. The RRD rose has the most acidic soil surface, the most nitrogen (hence salt), and the least water in hot summer.

U. of Connecticut Integrated Pest Management has a good site on mites and aphids. Here's their excerpt on aphids " Avoid high nitrogen fertilization that promotes lush growth favorable to aphids. Outdoors, natural enemies can help keep aphid populations in check. These include ladybird beetles, lacewings, flower flies, predaceous midges, and parasitic wasps."

For NATURAL spider mite control, National Geographic site has many good tips: 1) spray soap 2) spray rosemary oil 3) keep plants healthy & well-watered.

Some good news from West Virginia site on "Biological control agents of Multiflora rose" .... Here's an excerpt:

"Also, several predators of P. fructiphilus have appeared in West Virginia: a thrips (unidentified), a small cecidomyiid fly (unidentified), and several species of mites in the families Phytoseidae, Tydaeidae, and Anystidae. The combined activities of these predators and a parasitic fungus may have reduced field populations of the vector, thus slowing the observed spread of RRD."

Here is a link that might be useful: Organic ways to get rid of spider mites

This post was edited by Strawberryhill on Wed, Apr 17, 13 at 17:24

Roundup does not cause aphids. I haven't used round up in years, yet I had a bad aphid infestation last fall. The weather stayed warm, the roses put out new growth and there you have it.

And it isn't just roses with multiflora parentage that get RRD. Far from it. And I doubt horse manure prevents it.

Many/most? Rose Rosette articles are now warning that Round-Up damage can be mistaken for Rose Rosette virus infection. However, I feel that there should be more emphasis that other common yard and garden chemicals also should be suspect. In particular weed and feed applications to one's lawn especially uphill from one's rose beds.

Here is a link that might be useful: My comments

Thankfully I have only lost a few roses to RRD so far . I wish there were clear early warning signs, or a definitive test, as I have several roses I am keeping very close tabs on. I am reaching the point where most of my 80-odd roses are reaching maturity. The idea that RRD could move through and destroy half, or more, of my roses is upsetting to say the least.

Many very experienced rose gardeners, like Michael, have suffered drastic losses in their gardens. The constant comments about round-up, and the unusual ideas from someone who lost one rose, are irritating to experienced growers with real worries about this disease.

Hi Maureen: My goal is the same as yours: to identify what cause RRD and to prevent it. I explore all factors, and not just Round-Up! Prevention is better than treating it once it happens. Whatever I post are NOT my ideas, they are researches done by University Extensions across the countries.

Thank you, Buford - I agree on all points:

1) Aphids is climate and soil dependent. My clay is like a very slow released-fertilizer, and new growth is slow in my zone 5a. Aphids feed on soft and fast new growth in warm weather.

For my soil and climate, aphids infestation occurred when I fed it high-nitrogen CHEMICAL fertilizer in spring (15 years ago in acidic clay). In my present house with alkaline clay, I do late-fall fertilization with manure, so the new soft growth occurs in EARLY cold spring, so far no aphids for the last 13 years.

I only speak for myself, I don't speak for others in their different soil/climate.

I also agree with Buford that RRD does not limit to multiflora. However, multiflora is shallow and suckering type of root, more susceptible to lack of water. It took me less than 5 minutes to dig up that RRD with multiflora parentage, compared to 1 hour digging up Dr. Huey.

Dr. Huey is a very deep-rooted system, which is more drought-tolerant, thus the plant is stronger to fight against mites. There are only a few areas of California with RRD. Why? Mites flourish in humid weather, Michaelg's climate is humid, versus dry California climate.

Mites don't like alkalinity and can be easily killed with soap spray (pH 8 to 9). California is mostly alkaline soil, or alkaline water.

Mites flourish when the plant is weak or short of water. Michaelg has sandy soil, versus my wet heavy clay. The rose affected with RRD was the only one next to a large tree, a very dry spot.

RRD mites is carried by wind, Chicagoland is very windy, but I don't know why my other 45+ roses don't have RRD. I only had one RRD rose, which got the least water, and I removed completely.

Hi Henry: I use weed & feed on my lawn, right before a heavy rain, 2 to 3 times a year. However, that RRD rose was in the middle of a HUGE BED, surrounded by black plastic to kill grass. There's no lawn within 6 feet in all directions, it's all black plastic, so weed & feed has no play.

My other 45+ clean roses are the ones that got contaminated by weed & feed since they are planted near the grass. Why haven't they gotten RRD?

I'm convinced that multiflora rose got RRD because it's weakest, with the least water. And its shallow root can't access the deep water, and heavy clay as well as Dr. Huey. There was a Knock-out grafted on Dr. Huey in that exact spot, which I moved elsewhere (is still healthy).

This post was edited by Strawberryhill on Thu, Apr 18, 13 at 11:09

The following was stated: "My other 45+ clean roses are the ones that got contaminated by weed & feed since they are planted near the grass. Why haven't they gotten RRD?"

H.Kuska comment: I assume that you mean "why haven't they gotten herbicide damage from the weed and feed run off?"
You have stated that the one that showed RRD infection had a shallow root system (in heavy clay). You also state: "However, multiflora is shallow and suckering type of root, more susceptible to lack of water. It took me less than 5 minutes to dig up that RRD with multiflora parentage, compared to 1 hour digging up Dr. Huey." Another statement: "My only rose with RRD which I removed is NEVER mulched with horse manure. It's an own-root with multiflora genes. I don't give it alkaline horse manure because multiflora prefers acidic soil. Instead I gave it acid fertilizer high in nitrogen. "

------------------------------------------
So what does this give us?
Some herbicides are tied up (chelated) in the soil. Add acid and the mobility of the herbicide is increased.

Other roses have deep roots (and in clay) this one rose has shallow roots (and in clay). Where does rain water go after it passes through the weed and feed area? Is most of it going down through the clay to the deep roots or is most of it staying near the surface?

Upthread there were some generalizations about what makes mite populations soar.

There's a big problem: the mites that are RRD vectors are eriophyid mites, and there are, according to THE expert with whom I spent hours for the past three days talking mites and RRD, no such studies for the eriophyid mite that vectors RRD. You can't extrapoliate that way (good that you tried).

Look up Phyllocoptes fructiphillus, start with the references in the bibliography at the end of my ebook. For a general reference borrow the huge Springer book Eriophyidae through interlibrary loan.

Here is a link that might be useful: Rose Rosette Ebook

There has been much more research done on the wheat curl eriophyid mite which transmits a virus similar to rose rosette virus. It appears that there is a good chance that the conclusion about the need for moisture will be proven to be correct.

"Wheat curl mite have been shown to survive without food or water for less than 8 h at 24 C and 30��"40 h at 3 C. However, on sterile agar culture plates, the mites survived for longer periods. These survival times indicate that WCM cannot survive dry conditions for extended periods (del Rosario and Sill 1965; Jeppson et al. 1975). During an experiment in Texas, USA, WCM colonies were maintained for several months at 5 C, although with low egg viability (Skare et al. 2002). All stages can survive for at least 3 months at near freezing temperatures including several days at around-18 C (Townsend and Johnson 1996). Warm and humid conditions appear to be ideal for optimal growth in WCM development (Coutts et al. 2008b; Schiffer et al. 2009; Somsen and Sill 1970). CLIMEX analysis of WCM distribution in Australia suggests that the species has an ability to persist in both semi-arid and temperate areas, with distribution limited by heat and dry stress (Schiffer et al. 2009)."

" These mites are usually very susceptible to dry conditions (Jeppson et al. 1975)."

From: http://link.springer.com/article/10.1007/s10493-012-9633-y#

Journal: Experimental and Applied Acarology,
February 2013, Volume 59, Issue 1-2, pp 95-143

Title: Wheat curl mite, Aceria tosichella, and transmitted viruses: an expanding pest complex affecting cereal crops

Authors: Denise Navia, Renata Santos de Mendonça, Anna Skoracka, Wiktoria Szydło, Danuta Knihinicki, Gary L. Hein, Paulo Roberto Valle da Silva Pereira, Graciela Truol, Douglas Lau

Here is a link that might be useful: link for abstract

I reference a free 2012 leaf curl master's thesis
"Transmission of Triticum mosaic virus and its Impact
on the Biology of the Wheat Curl Mite Aceria
tosichella Keifer (Eriophyidae), and an Evaluation of
Management Tactics for the Wheat Curl Mite and
the Wheat-Mite-Virus Complex"

in an earlier thread about rose rosette virus:

http://forums2.gardenweb.com/forums/load/roses/msg101551485093.html

Here is a link that might be useful: link for earliet thread

Would an RRD (or rather mite) infestation in the UK be a remote possibility? Highly likely in the future? Not really?
Apols if this is a ridiculous question.

There is a 2010 review: "Adventive eriophyoid mites: a global review of their impact, pathways, prevention and challenges"

If you cannot obtain a copy, I can e-mail you one.

The short answer is yes. Because of international trade it has and is happening for the other eriophyoid mites.

Campanula-- rose plants imported from the US could carry the mite and the virus to other parts of the world. The British climate would probably be comfortable for the mite. Spread within a country is facilitated by having lots of roses to provide bridges for the mites, which travel on the wind and alight by accident. The role of multiflora rose in the US is that it grows densely in the wild over most of the eastern and midwestern states, providing lots of bridges between gardens. I don't know whether the abundant wild roses in the UK are resistant. Anyway there are probably enough garden roses in the London suburbs to support the spread of RRD.

This post was edited by michaelg on Thu, Apr 18, 13 at 17:04

THANK YOU, Henry, for taking the time to do research... I appreciate that very much.

I also appreciate Henry, Michaelg, Buford, Ann Peck, and Camp. for giving info., rather than attacking anyone. Here's more info. from my garden:

1) That bed was made 12 years ago, before I used Scott's weed & feed via a broad-cast spreader for my lawn. So the soil there is 100% freed of weed & feed.

2) I dug the healthy Knock-out and put it elsewhere. Then I bought that multiflora-rose from Home Depot ... super healthy for 2011 summer. It was the wettest summer with 49" of rain. I made the bed bigger by putting black plastic to kill grass.

3) Second year 2012: Last spring was dry ... we had drought until September. That rose was not watered, it's next to a tree, and came down with RRD in July.

4) For the past 13 years we have mites everywhere: even inside the house .. black tiny dots. Years ago my neighbor sprayed the entire back yard to kill mites, so her dogs can be clean.

My conclusion: Mites are every where, but they afflict only the rose that was most weak & dry. My alkaline wet clay keep other roses clean, until I put a shallow-root multiflora next to a tree. The high-nitrogen acid-fertilizer certainly attracted pests and mites.

The rose is also stressed with the high-salt in high-nitrogen fertilizer. Then came the drought, which finalized in being vulnerable to pest-taking over via RRD.

Strawberry,
The thing to remember in any part of this country where Rose Rosette is, is that disease pressure will vary from year to year.
The way a rose gets RRD is also dependent on the nature of the rose. In my own garden, polyanthas that are 1/2 and 1/4 multiflora (as reported in their parentages) have come down with RRD at much higher rates than polys in the same bed that are more complex in their breeding.

There is something about the distance the the eriophyid chiliceral stylet has to reach into a part of the rose to get to undifferentiated meristemic material.......that is easier to reach on multiflora and its offspring.

About seeing mites: The mites that spread RRD are NOT the mites you are seeing. The mites that spread RRD are about 100 microns long and 20-30 microns wide, about the size of the bottommost segment of an aphid's foot.

Have you checked upwind of your roses for a sick multiflora?

The following was stated: ' That bed was made 12 years ago, before I used Scott's weed & feed via a broad-cast spreader for my lawn. So the soil there is 100% freed of weed & feed.'

H.Kuska comment. Anytime it rains, the soil downhill from where weed and feed was recently applied will contain herbicide. For a clay soil it may only be near the surface.

'The second type of herbicide damage that I will mention is due to Weed and Feed type products that contain atrazine as the active ingredient. Atrazine only kills broad leaf weeds so it is used to kill weeds in residential lawns. Unfortunately for rose growers it is very water soluble and can damage roses down hill from the application area. Is this only a possibility or has it been tested by experiment? The linked to paper reports what happened to the rose Canna hybrida `King Humbert' when exposed to atrazine runoff.'

Here is a link that might be useful: rose Canna hybrida `King Humbert' when exposed to atrazine runoff.'

Strawberryhill, the suggestion of reducing water on leaves below appears right in line with what you concluded.

"Current control strategies include keeping roses in good vigor, pruning, mite control, and cultural controls such as reducing water on leaves."

Here is a link that might be useful: link for above

Thank you, Henry, for the info. Henry: my front lawn is FLAT, there's no run-off of weed-feed. The RRD rose was ISOLATED by large sheets of black plastic since I enlarged the bed.

Thank you, Ann, for asking me "Have you checked upwind of your roses for a sick multiflora?" Yes, I walk everyday in my neighbor hood. None! Grafted on Dr. Huey dominates the market here, sold cheap everywhere. We have alkaline clay so Dr. Huey dominates.

Eriophyid mites DO NOT have phloem-piercing mouthparts. Only if the rose is weakened, then mite can gain entry to the tissue. From my microbiology class, mites serve as a vector to carry the virus. But the virus has to enter the tissue to screw up the RNA.

Here's an abstract "Ringspot symptoms in European mountain ash (Sorbus aucuparia L.), fig mosaic, rose rosette, raspberry leaf blotch, pigeonpea sterility mosaic (Cajanus cajan) and High Plains disease of maize and wheat were found to be associated with viruses that share several characteristics. They all have single-stranded multipartite RNA genomes of negative orientation."

How can a tiny mite without fangs bite the plant? How can a tiny virus hi-jack the RNA replication? Only if the plant is weak. Potassium and calcium regulates the osmotic integrity of the cell membrane. If there's not enough water, nor those 2 vital nutrients, the cell membrane is weak, thus allowing break-in.

My rose affected with RRD was an own-root, but with multiflora parentage, thus the shallow root, and susceptibility to drought. The common cold is caused by a virus, but not everyone catch a cold, if their immune system is strong. Only the one with the weakest immune system are susceptible to take-over by a tiny virus.

My neighbor is the Queen-of-Round-Up. She made 3 large roses bed, by killing grass with canisters of Round-up. She has 30+ knock-outs planted in those beds, all grafted on Dr. Huey. They are 100% healthy for the past 12 years.

I'm within walking distance of her house. I'm afflicted with Japanese Beetles, she doesn't. Her house is next to a pond and a creek. She has plenty of birds and insects to be predators to pests. Plus she waters her roses religiously every other day in hot summer.

My RRD rose was in the hot and dry bed, next to a tree. We had the drought, plus over 100 degrees temp. All the predatory insects hang out in the cool shady & well watered roses (bees, wasp, weird insects from horse manure). The only ones that can survive the full hot sun, and dry soil are the mites ... and they took over that weak and shallow root multiflora. Plus I dumped acid fertilizer high in nitrogen on that rose.

Here's an excerpt from U. of Illinois Extension: "For example, increased nitrogen fertilizer rates have been associated with large increases in numbers of aphids and mites." See link below.

Here is a link that might be useful: Managing the soil to reduce insect pests

"Eriophyid mites DO NOT have phloem-piercing mouthparts. Only if the rose is weakened, then mite can gain entry to the tissue. From my microbiology class, mites serve as a vector to carry the virus. But the virus has to enter the tissue to screw up the RNA.

Here's an abstract "Ringspot symptoms in European mountain ash (Sorbus aucuparia L.), fig mosaic, rose rosette, raspberry leaf blotch, pigeonpea sterility mosaic (Cajanus cajan) and High Plains disease of maize and wheat were found to be associated with viruses that share several characteristics. They all have single-stranded multipartite RNA genomes of negative orientation."
"

BUT, the expert on the mite knows that the mites do not burrow into the plant. They are surface dwellers. Looking at sites of first infection, many from photographs I've taken, lead to the logic that the transmission is into UNDIFFERENTIATED MERISTEMIC TISSUE. Yes, I'm going to be loud about it, because I've said it so often and it makes much more logic than what you suggested.

Once cells are grown and not infected, they do not then all of a sudden go bonkers, It happens to new cells that come out of meristems.

Weakness of the plant has nothing to do with it. What we see is that the healthiest plants with larger masses are most susceptible, just based on the odds of having so many, many sites of potential infection.

Or, feel free to follow your textbooks. It's a free world and you are free to interpret as you choose.

(Have you ever heard of predaceous thrips preferring bright sunny and dry fields?)

The following was stated: "My neighbor is the Queen-of-Round-Up. She made 3 large roses bed, by killing grass with canisters of Round-up. She has 30+ knock-outs planted in those beds, all grafted on Dr. Huey. They are 100% healthy for the past 12 years. "

H.Kuska comment. I feel that the case about Round-Up drift (above ground and through the soil) has been studied sufficiently to warrent caution about using Round-Up in and near rose beds in general. Why your neighbor's soil "locked up" enough of the Round-Up to prevent noticable damage would require specific knowledge about her soil.

------------------------------------------------------

Here is one more scientific study: " Very small amounts of glyphosate were mobilized, but its transformation product aminomethylphosphonic acid was detected at higher concentrations, in more storm events, and at greater depth in the soil profile."

http://pubs.acs.org/doi/abs/10.1021/es034847h
------------------------------------------

We now have the additional fact about the present case being on level soil. Thus, the present case is one of using a weed and feed which contains a very water soluble herbicide on level clay soil in the same yard as a rose bed. Even in a case of level land, I would not recommend such a practice as it will probably not all go straight downward in overflow conditions such as a rainstorm.

Of course, being next to a tree is consistent with the model that a windbreak would cause the mites to drop, so it is possible that it was RRvirus. Hopefully an inexpensive test will be made available so that one could be more positive as to the cause of "symptoms".

Here is a link that might be useful: link for herbicide runoff study

It is my understanding that references to "UNDIFFERENTIATED MERISTEMIC TISSUE" is to tissue that is the result of the mite feeding not to where it feeds.

"Results of comparative anatomical studies made on the stained sections of normal and galled leaves enabled to locate marked variations in cell structure and form. Extensive injuries could be observed in the structure of mesophyll in the galled tissue, which was found modified into undifferentiated meristematic zone .This could be accounted due to the injection of salivary toxins [ 18 ] by the deutogyne of A. pongamiae , for digesting the cuticle and cellulose of the cell wall, as reported earlier [ 19��" 22 ] .
Subsequently, the deutogyne would pierce the leaf tissue by inserting its cheliceral stylets, resulting in the formation of feeding punctures to suck out cell sap."

----------------------------------
In the 2012 master's thesis that I referenced earlier, the following appears: "To avoid desiccation, mites migrate to the inner whorl of a newly emerging leaf shortly after landing on a new host. There they feed between the veins of the plant on a thin epidermal layer of tissue known as the bulliform cell. These cells are important in the unrolling of the leaf as it emerges (Esau 1953). WCM feeding prevents the leaf from uncurling, causing subsequent leaves to become trapped. The curled leaf provides an ideal environment for mite survival. WCM will continue to feed on the leaves, migrating to each newly emerging leaf. Mites also colonize the wheat head as it emerges. Within the wheat head mites live in secluded sites and feed inside the glumes (Kantack and Knutson 1954)."

---------------------------------------

Here is a link that might be useful: Prospects in Bioscience: Addressing the Issues

If you are interested in what scientists can do in studying Eriophyid mites, the follow 2005 full paper is available free. It has excellant pictures that may help motivate your children, grandchildren, other young relatives to major in plant science.

The comments on what is known and what is not known about Eriophyid mite feeding should also be of interest as some young people may assume that there is nothing further to study in plant science.

Here is a link that might be useful: link for above

Henry,
The Undifferentiated Meristemic Tissue refers to the rose disease, not the wheat/corn disease. The mites that vector RRv are on the stems next to the bracts and also in the whirled area.

Where the corn/wheat people are 'lucky' if we can call it that is that they are dealing with annuals and the infection/transmission times, esp into corn, are very limited.

Strawberryhill, your comments about the health of the plant are consistent with the suggestions from the recent rose rosette disease summit: "Current control strategies include keeping roses in good vigor.....".

The following was stated: "The Undifferentiated Meristemic Tissue refers to the rose disease, not the wheat/corn disease."

H.Kuska comment. Sorry, I do not understand what this statement is meant to mean. The 2013 link I gave and the quote I presented is specifically about:

"The present study describes the morphological and anatomical changes induced by the feeding activity of various developmental stages of the mite A. pongamiae on the leaves of P. pinnata."

Since it is a 2013 paper, the editor, reviewers, and the authors should be up to date on what is known about the feeding mechanism of eriophyid mites.

You had stated the following: "There is something about the distance the the eriophyid chiliceral stylet has to reach into a part of the rose to get to undifferentiated meristemic material.......that is easier to reach on multiflora and its offspring."

H.Kuska comment. What I am saying is that I think that you have it backwards, the mite does not go TO undifferentiated meristemic material, it CAUSES undifferentiated material to form as the initial part of its feeding process.

Does the mite have a particular flying (floating?)/feeding cycle? Is it active throughout the entire growing season or, does it occur in cycles.
Is there any hope of temporary covers such as horticultural fleece (I use this when carrot fly is about, and also pea moth)?
Obviously, I am certain all avenues will have been explored but if there is any chance of this reaching the UK, knowledge is the best defence.......

Henry,
I disagree with your take on the situation as it applies to roses. The mite scientist I talk to does as well. If your hypothesis worked, we'd see RRD growths emerging all along the stems; we don't. They emerge where the bracts are already as well as apically.
I asked him if we can extrapolite mite behaviour from one mite to another in the same genus; his answer was no.

Campanula,
The mite cycle is still being studied and a bit more of its overwintering cycle was found just this past winter. Another problem for North America is that there are variations that seem to be dependent on temperature, on environmental dryness that are only beginning to be defined.

The problem with barriers are the sizes of the vectors (and the sizes of roses). These eriophyids are as small as the foot part of an aphid.

Noone wants to think that roses might have to have the level of replanting that you do to keep on growing Black Currents (whose disease is similar, also eriophyid vectored, and studied for a lot longer.)

I only speak for myself, and not for others. To generalize about issues would be playing God, and imposing assumptions on others.

For that particular RRD rose that I removed, the acid nitrogen fertilizer NPK 10-5-4 which I used is the culprit. In our cold zone 5a, we have to stop fertilizing mid-August, otherwise the new growth can't harden for winter survival.

Here's a quote from the site below on nitrogen: "Excess of nitrogen might result in poor root system, soft tissue, delay in harvestable products, low quality yield and higher susceptibility to disease and pests."

If you google basic info. about mites, Wikipedia wrote "Two-spotted spider mites eat soft tissue and juice of American elm trees and house plants."

If you google how mites feed on your plants, University of Illinois Extension wrote "Nitrogen is the primary plant nutrient needed by insects with piercing-sucking and chewing mouthparts. Nitrogen is very important for insect growth, development, and reproduction. Nitrogen levels are usually higher in younger tissue than in older leaves."

When the plant tissue is soft, pests can feast on it easily, be it aphids or mites. That RRD rose was in its 2nd year, a tiny bush (2' x 1'). But it was throwing octopus canes from the nitrogen I gave, so I asked Kim Rupert, the breeder, to check on its parentage to see if it's related to an Austin.

He told me that it has multiflora parentage. Since multiflora becomes chlorotic, or pale in my alkaline clay, I gave it MORE acid fertilizer for azaleas, which happens to be high in nitrogen NPK 10-5-4.

Yes, that tiny bush was blooming like mad in May, when we had tons of rain.... then came the drought last summer, and it came down with RRD in July, when the temp. was over 100 degrees. That was our hottest and driest year. It's also planted right next to a tree.

Our spring in Chicagoland is very wet. Yesterday we had flash flood with road-blocks & river overflowed. Cantigny rose park, 15 minutes from me, with 1,200 roses don't have RRD. Theirs is alkaline clay with frequent irrigation, and roses grafted on deep root Dr. Huey.

Why is that high-rain and cooler climate like Pacific Northwest don't have RRD? Seil in Michigan with roses in pots don't have RRD either - her climate is cooler than mine, with lots of rain.

Here is a link that might be useful: How nitrogen works, how plant uses it

This post was edited by Strawberryhill on Sat, Apr 20, 13 at 12:39

I'll include the link for University of Illinois Extension on the different ways that different insects gain access to the inside of the plant.

RRD mite is the vector that carries the virus which screws up the RNA replication process that manufactures new growth. But the virus has to get inside the tissue of the plant to set up house. The link below wrote:

"Plants that are overfertilized, especially with nitrogen-based fertilizers, produce succulent growth, increasing susceptibility to plant-feeding insects and mites. The higher levels of amino acids, which are the primary food source used by insects and mites, can increase their reproductive ability.

In addition, plants that receive excessive levels of fertilizer may have thinner leaf cuticles, which are easier for insects and mites to penetrate with their mouthparts."

Here is a link that might be useful: University of Illinois on how insects feed

Curses, would that be the big bud mite, Anne? I am totally familiar with blackcurrant big bud mites and have to work to a 5 year cycle - even less as I was unable to convince my neighbours to change their bushes, despite showing them the outsize buds on their bushes and the reversion disease is not easy to spot until cropping more or less stops altogether. I have a continual cycle of hardwood cuttings on the go and can usually only guarantee having a fully cropping bush for 2 seasons before the bushes are attacked....but because we MUST have blackcurrants (it is impossible to buy fresh fruit anywhere in the UK because a certain juice company uses 95% of commercial crops) - we put up with it - including an exotic array of nets, fleece and various pruning methods such as redcurrant cordons. And, like roses, replant issues mean that I have actually run out of space on my allotment and am now planting random bushes all over the plot....However, over the past decade, most of the diseased bushes on the rest of the site have finally been removed (by me,sneakily, during tenancy changeovers) and not replaced so, this year, I am the only one growing them - might be able to stay on top.
What about fleece - this is a white, papery material, used to prevent freezing, but without the holes found in fine netting?
Mind, if I had to swathe roses in this for months at a time, I would really have to reconsider becoming a deutzia collector.
Thank you for the heads up, Ann, hope your work yields success in the near future.

The following statement was made: "I asked him if we can extrapolite mite behaviour from one mite to another in the same genus; his answer was no."

H.Kuska comment. Of course each species has its own unique characteristics. This is probably why each species is so selective as to which plant it feeds on.

James W. Amrine has coauthored a review article titled: "Behavioural studies on eriophyoid mites: an overview"

This review indicates (to me) that eriophyoid mites have characteristics in common such that it is worth while to write a general review. But of course they also have differences.

Concerning feeding it states: "Finally, after landing on the host and discriminating whether it is a proper one, the eriophyoid mite can start to feed. After probing, which takes several seconds, the mite takes a typical feeding stance, i.e. it slightly bends its body and anchors the rostrum to the host surface and contracts the telescopic palpal segments, which allows protrusion of the cheliceral stylets for a short distance into the plant tissues (Krantz 1973; Gibson 1974; McCoy and Albrigo 1975; Nuzzaci 1976). Information concerning the feeding behaviour of eriophyoid mites was summarized by Westphal and Manson (1996) and no new detailed data have been provided since."
http://link.springer.com/content/pdf/10.1007%2Fs10493-009-9319-2.pdf

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I consider Dr. Raymond A. Cloyd (Professor and Extension Specialist in Ornamental Entomology/Integrated Pest Management Department of Entomology at Kansas State
University, to be one of the mite experts among rose rosette virus interested scientists.
" Rose rosette is vectored or transmitted by the eriophyid mite, Phyllocoptes fructiphilus, which is native to North America. Phyllocoptes fructiphilus is robust, spindle-shaped, and yellow to brown in color, 140 to 170 microns in
length, and approximately 50 microns in width. The mite has four legs, which differs from other mite species that
typically have eight legs. Mites may be observed with the use of 10X hand-lens or high-powered (200X) microscope.
The mites are typically located in the angles between leaf petioles and axillary buds. Adult mites overwinter on rose canes between partly opened buds and the angles between rose stems and petioles. Phyllocoptes fructiphilus needs living, green tissue in order to survive. In early spring, the mites migrate onto developing shoots where females lay eggs. Females may live up to 30 days; laying one egg per day. Young mites develop within the leaf folds of new shoots or under leaf petioles. The mites may move from plant-to-plant via attaching to insects. They may also be dispersed via air currents (wind) from infested rose plants. Mites may start a new infection, by feeding on the succulent, rapidly growing tissues, after landing on an un-infected garden plant or multiflora rose."

H.Kuska comment. Please note: "by feeding on the succulent, rapidly growing tissues,"

http://www.ars.org/wp-content/uploads/2012/04/Dr-Cloyd-Rose-Rosette-Disease-April-2011.pdf

Here is a link that might be useful: link for Dr. Cloyd's article

Michael, I am so very sorry to hear about your roses. I am especially worried because we share the same geographical footprint, so to speak. I feel certain, too, that some of the roses over at the Griffing Circle garden are infected- some looked awfully bad to even my untrained eye late last summer. Having only gotten hooked on roses in the past couple of years, I would be just devastated to lose any to this vile disease. I already lost a few to voles. (Yes be on vole alert too! They are very active this year in our neck of the woods.) Sigh. I will have to be on a vigilant watch for symptoms. Nichole

This post was edited by belle_va on Wed, Apr 24, 13 at 23:53

Nichole, I have removed several infected roses from the Griffing garden over the years, but it is hard for me to get over there nowadays. The city uses Roundup there, so you have to distinguish. I believe I can tell the difference. The garden at the Red Cross has also had casualties, one or two per year.