I just noticed a couple of rose bushes with the dreaded BS. Outs been so wet here in central Illinois .
Can anyone comment from their experience, which is the best overall fungicide for roses??one that stops BS in its tracks!
Bayer Advanced Garden Disease Control for Roses, Flowers, and Bushes. Just don't confuse it with Bayer 2-in-1 or Bayer 3-in-1 which everyone will try to sell you instead. They have insecticides and fertilizers in them also--you don't need all of that. Just get the fungicide I listed first. You will probably have to go to Lowes to get it--places like wal-mart or home depot don't carry it. Or you can order it online and get it within a few days.
Follow directions and spray only on a windless day--usually before 10 in the morning, although the winds will often calm down to almost nothing late in the afternoon sometimes. The rose leaves will need several hours to dry off.
Bayer will stop the infection but will not eliminate the spots that are already there. It will also keep any new infection away for at least a couple weeks. You might need to spray every 2 weeks for a while if the BS pressure continues heavy and long. I usually find 1-2 times is enough for quite a while.
You will need a plastic hand-pump sprayer (costs maybe $20)--got mine at Home Depot, but I assume Lowes has it also.
Check the name carefully--I'm not kidding--they will try to sell you the stuff you do not want.
What Kate said but I'll add a couple of tips. Water everything very well the day before you spray. It helps if the roses are well hydrated before spraying. I know it's still cool right now but for future reference you should never spray anything if the temps are over 80 degrees. That's too hot and the leaves could burn.
Thank u both for the great info! Kate, I will definitely be getting the first product mention. Appreciate the reply,
Happy Gardening :)
The active ingredient in Bayer Advanced Disease Control is tebuconazole. Even though tebuconazole is a German product, the European Union has banned tebuconazole as of 2018.
"Most of the pesticides concerned are produced by German chemical industry giants Bayer or BASF, and include Amitrol, Ioxynil, Tepraloxydim, Epoxiconazole, Iprodion, Metconazole, Tebuconazole and Thiacloprid."
Apparently the reason for the ban is: "Due to the potential for endocrine disrupting effects, tebuconazole was assessed by the Swedish Chemicals Agency  as being potentially removed from the market by EU regulation 1107/2009."
Title: Combined exposure to endocrine disrupting pesticides impairs parturition, causes pup mortality and affects sexual differentiation in rats.
Authors: Jacobsen PR, Christiansen S, Boberg J, Nellemann C, Hass U.
Authors affiliation: Department of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, SÃ¸borg, Denmark.
Published in: Int J Androl. 2010 Apr;33(2):pages 434-42.
Abstract: "Risk assessment is currently based on the no observed adverse effect levels (NOAELs) for single compounds. Humans are exposed to a mixture of chemicals and recent studies in our laboratory have shown that combined exposure to endocrine disrupters can cause adverse effects on male sexual development, even though the doses of the single compounds are below their individual NOAELs for anti-androgenic effects. Consequently, we have initiated a large project where the purpose is to study mixture effects of endocrine disrupting pesticides at low doses. In the initial range-finding mixture studies, rats were gavaged during gestation and lactation with five doses of a mixture of the fungicides procymidone, mancozeb, epoxyconazole, tebuconazole and prochloraz. The mixture ratio was chosen according to the doses of each individual pesticide that produced no observable effects on pregnancy length and pup survival in our laboratory and the dose levels used ranged from 25 to 100% of this mixture. All dose levels caused increased gestation length and dose levels above 25% caused impaired parturition leading to markedly decreased number of live born offspring and high pup perinatal mortality. The sexual differentiation of the pups was affected at 25% and higher as anogenital distance was affected in both male and female offspring at birth and the male offspring exhibited malformations of the genital tubercle, increased nipple retention, and decreased prostate and epididymis weights at pup day 13. The results show that doses of endocrine disrupting pesticides, which appear to induce no effects on gestation length, parturition and pup mortality when judged on their own, induced marked adverse effects on these endpoints in concert with other pesticides. In addition, the sexual differentiation of the offspring was affected. This as well as the predictability of the combination effects based on dose-additivity modelling will be studied further in a large dose-response study."
A full 2007 reviewed scientific paper:
"Endocrine-Disrupting Activities In Vivo of the Fungicides Tebuconazole and Epoxiconazole"
It is my understanding that it is banned in New York State.
Here is a link that might be useful: link for wikipedia
Yes, I would recommend you don't eat your roses after you spray them.
This is from a very new "Available online 28 April 2013
In Press, Corrected Proof" reviewed scientific paper.
"In conclusion, a cytotoxic effect of the tebuconazole-based fungicide in bovine peripheral lymphocytes was established. Considering the human and animal exposures to the fungicide, a statistically significant increase in the CA and SCE frequencies in bovine peripheral lymphocytes also provides the data on the potential clastogenic/genotoxic effects of the commercial fungicide that could result in adverse health consequences."
H.Kuska comment. I recommend utilization of the Precautionary Principle.
Here is a link that might be useful: link to copy of full
Well, it's really not a matter of eating your roses but more a matter of releasing a toxic agent into the atmosphere where it has the potential to harm any number of beneficial insects and birds. I would concentrate more on finding roses that are very resistant to blackspot than spraying possibly or probably harmful chemicals around for the sake of a few roses. My roses have had terrible mildew and before that blackspot this spring, but both have now mostly resolved with the warmer weather. My worst-affected plant with blackspot I cut down to the ground. If it continues to have that problem it's gone from my garden. There are plenty of other roses that are more resistant.
I just don't want people who read this forum to be afraid of asking about sprays because of the strong views of a couple of members. While we are all in awe of @henry_kuska's ability to google, and we are all fond of reading the endless links to wikipedia entries, the original poster asked which would best solve their disease problems. Presumably, they had already decided they were happy to use sprays, and will use them responsibly. So to my mind, instead of trying to force ones philosophy onto others, a simple response to the query, such as that of @seil and @dublinbay is probably more the type we should be offering. Mine was a tad sarcastic, and for that I hang my head in shame lol
The following was stated: "Presumably, they had already decided they were happy to use sprays, and will use them responsibly."
H.Kuska comment. I do not understand how someone can use a chemical responsibility unless he/she is aware of what scientists are saying about the potential dangers of the use of that chemical.
"Abstract. Risk assessment is currently based on the no observed adverse effect levels (NOAELs) for single compounds. Humans are exposed to a mixture of chemicals and recent studies in our laboratory have shown that combined exposure to endocrine disrupters can cause adverse effects on male sexual development, even though the doses of the single compounds are below their individual NOAELs for anti-androgenic effects. Consequently, we have initiated a large project where the purpose is to study mixture effects of endocrine disrupting pesticides at low doses. In the initial range-finding mixture studies, rats were gavaged during gestation and lactation with five doses of a mixture of the fungicides procymidone, mancozeb, epoxyconazole, tebuconazole and prochloraz. The mixture ratio was chosen according to the doses of each individual pesticide that produced no observable effects on pregnancy length and pup survival in our laboratory and the dose levels used ranged from 25 to 100% of this mixture. All dose levels caused increased gestation length and dose levels above 25% caused impaired parturition leading to markedly decreased number of live born offspring and high pup perinatal mortality. The sexual differentiation of the pups was affected at 25% and higher as anogenital distance was affected in both male and female offspring at birth and the male offspring exhibited malformations of the genital tubercle, increased nipple retention, and decreased prostate and epididymis weights at pup day 13. The results show that doses of endocrine disrupting pesticides, which appear to induce no effects on gestation length, parturition and pup mortality when judged on their own, induced marked adverse effects on these endpoints in concert with other pesticides. In addition, the sexual differentiation of the offspring was affected. This as well as the predictability of the combination effects based on dose-additivity modelling will be studied further in a large dose-response study."
There is growing concern of permanent damage to the endocrine and nervous systems after developmental exposure to endocrine disrupting chemicals. In this study the permanent reproductive and neurobehavioral effects of combined exposure to five endocrine disrupting pesticides, epoxiconazole, mancozeb, prochloraz, tebuconazole and procymidone, were examined. Pregnant and lactating rat dams were dosed with a mixture of the five pesticides at three different doses, or with the individual pesticides at one of two doses.
Adverse effects were observed in young and adult male offspring from the group exposed to the highest dose of the mixture. These included reduced prostate and epididymis weights, increased testes weights, altered prostate histopathology, increased density of mammary glands, reduced sperm counts, and decreased spatial learning. As no significant effects were seen following single compound exposure at the doses included in the highest mixture dose, these results indicate cumulative adverse effects of the pesticide mixture."
The present study investigated whether a mixture of low doses of five environmentally relevant endocrine disrupting pesticides, epoxiconazole, mancozeb, prochloraz, tebuconazole and procymidone, would cause adverse developmental toxicity effects in rats. In rat dams, a significant increase in gestation length was seen, while in male offspring increased nipple retention and increased incidence and severity of genital malformations were observed. Severe mixture effects on gestation length, nipple retention and genital malformations were seen at dose levels where the individual pesticides caused no or smaller effects when given alone. Generally, the mixture effect predictions based on dose-additivity were in good agreement with the observed effects. The results indicate that there is a need for modification of risk assessment procedures for pesticides, in order to take account of the mixture effects and cumulative intake, because of the potentially serious impact of mixed exposure on development and reproduction in humans."
This previous thread may be useful to avoid duplication.
Here is a link that might be useful: Bayer Advanced Disease Control--is it safe to use?
If the information presented has to do with the safety of our sisters and brothers here, I believe that presumption is irresponsible.
I for one am grateful for Henry's research. That his views are strong make them no less valid.
In addition, I would not like to see this turned into one of those boards where the truth is wrapped in pink cotton candy.
Roses have thorns, and rose growers are strong.
If you do not want to read the posts of a particular person that is your choice, but do not force that choice on others PARTICULARLY in this sort of case where the info may be important to future health.
I'd rather read reminders about precautions than ever, ever read a post by one of our members that said 'I wish I had known' because the cotton candy crew had discouraged the information the reader needed to make a real choice..
If you want to research something, research confirmation bias. The posts he writes aren't guidance, he hasn't the courage for that, instead of saying, 'I don't spray because...' or 'you shouldn't spray because...' he fills the forum with questionable science copied from wikipedia. He's trying to baffle with bullsh!t the people he can't blind with dodgy science. The chemicals in these sprays are licensed for mass use on edibles. They are sprayed in vast quantities by farmers all over the world. Are we really saying that the relatively miniscule amounts that are used on roses are such a big problem. If you want to stop spraying roses because rats fed with the stuff in a lab showed symptoms that's your prerogative. And posting that you wouldn't spray if you knew what you were talking about, which is pretty much what
"I do not understand how someone can use a chemical responsibility unless he/she is aware of what scientists are saying about the potential dangers of the use of that chemical"
means, takes arrogance to a whole new level.
Google Scholar is probably the main literature source that scientists now use. One of its main features is that it also includes what newer papers have cited a given paper. In most cases, the general public only gets to see the abstract of the paper without paying a fee (unless the journal is an open access journal). Often from a research university the full paper is available for download.
When using any literature search program, it is important to set up the search terms so that almost all of the papers of interest are found and that almost all of the not of interest papers are excluded.
For this thread the keywords tebuconazole and human delivers:
114 hits so far this year, 397 hits from 2012 to the present and 912 hits from 2009 to the present.
For this thread the keywords tebuconazole and health delivers:
128 hits so far this year, 462 hits from 2012 to the present and 1170 hits from 2009 to the present.
(Of course one could look at hits for the "any time" period, but science is normally cumulative so that the recent papers will contain citations to the earlier ones.) Unfortunately the "sort by date" function does not appear to function correctly.
I normally start with the 2013 papers and then work my way back.
Here is a link that might be useful: link for key words tebuconazole and health
A quote from you: "The chemicals in these sprays are licensed for mass use on edibles. "
Previously licensed chemicals such as DDT and Diazinon have been withdrawn from some markets due to safety concerns.
We all understand the world and how it works. Politics, corruption, and more innocuously, grants for chemicals which seem perfectly OK at the time but later prove to be unacceptably risky are all parts of today's world.
I'm not trying to make choices for others. What I am trying to do is preserve a climate where each of us can contribute and the reader can make up her/his own mind. We do not have to nanny people, I trust that readers are intelligent enough to looks at the pros and cons and decide what is right for them. Just the appearance of some of these articles may let people know that their own due diligence is required and to do more research. But to try to bully others into not posting vital information needed to decide on a course of action is unacceptable.
I hope we are trying to create a group of strong, intelligent, knowledgeable rose growers who make informed choices here.
This post was edited by lucille on Mon, May 13, 13 at 10:01
I came across this this morning. It is not about tebuconazole specifically but it is about endocrine disruptors in general and about paying attention to what scientific research is reporting.
The author is Brian Moench, president of Utah Physicians for a Healthy Environment and a member of Union of Concerned Scientists.
"It is a spring ritual for state agencies, farmers and gardeners to arm themselves with chemicals to wipe out insects and weeds, with little thought of the broader consequences. It is long overdue that this ritual give way to science.
Not surprisingly, chemicals that kill the cells of mosquitoes and dandelions just as easily do the same to beneficial insects, animals and humans. It is a misconception that doses of these chemicals commonly encountered are too small to matter.
Numerous physician/scientist groups, including the American Academy of Pediatrics, Physicians for Social Responsibility and the Endocrine Society have made unambiguous position statements about the danger of the chemical stew we live in, from pesticides in particular.
Europe just banned the most widely used class of insecticides. Medical science is now overwhelming ��" pesticides are poisons and should be thought of much as we do tobacco. Don’t smoke, and don’t spray.
Addressing the effect on the human embryo, the 15,000-member Endocrine Society ��" specialists in endocrine diseases ��" released this official statement on chemicals (like pesticides) that act as endocrine disruptors. "Even infinitesimally low levels of exposure, indeed, any level of exposure, may cause endocrine or reproductive abnormalities, particularly if exposure occurs during a critical developmental window. Surprisingly, low doses may even exert more potent effects than higher doses."
Here is a link that might be useful: Salt Lake Tribune article
"Previously licensed chemicals such as DDT and Diazinon have been withdrawn from some markets due to safety concerns."
Using the ban of DDT as an example of a good result because of the "concern for safety" is unfortunate. There were cities in Africa whose health statistics went from zero malaria deaths per year to over 100,000 deaths the first year following the ban. There are some estimates of over 50 million deaths worldwide because of the loss in poor nations of DDT as a cheap and effective tool to fight malaria. Yes, there are some real problems with DDT, but single minded fanaticism about its dangers ended up killing millions of people. Single minded fanatics have a way of missing the big picture like that.
"Single minded fanatics"
And that is EXACTLY why freedom to post about both sides of an issue is important. Put *all* the information on the table.
Look, chemicals can be dangerous. Even household chemicals. It's wise to know the risks and follow precautions. But we don't need scare tactics on every thread about spraying. I have cut down on chemicals that I use inside and outside. But I still spray my roses. I do it carefully, on a windless day. I wear eye protection and long sleeves/pants and gloves. I also use an extended spray arm, so I'm not near the spray. I wouldn't be able to grow roses if I couldn't spray.
Recently, because the weather has been crazy, and I couldn't get a good dry windless day on the weekend to spray, I've done it the past 2 times in the evening. And now I think that is preferable. The air is more still, you don't have to worry about the sun burning the leaves, and it's a lot cooler out. Try it!
gardenlady, if you are still reading, don't blame yourself for the major turn this thread took. It is not your fault. You have the answer above to your question (which is the best fungicide). If the information in the "take-over" interests you, by all means read it. If all that is much more than you were looking for, ignore it. Your choice. However, now you know that there is controversy in the rose world, don't you! : )
My practical advice is don't use a fungicide unless it is absolutely necessary; if you need to use it, use it as infrequently as possible while still getting the job done. Take some practical precautions: cover arms and legs, put those clothes in the wash immediately after you finish spraying and take a shower--just to be on the safe side. And spray only when there is very little to no wind (usually earlier in the morning)--you don't want a faceful of spray from stray breezes! Don't eat or smoke while spraying--until you have washed your clothes and body.
It is good to remember that these sprays can cause damage if mis-used, so read directions carefully.
And don't be surprised if my "practical" advice to you absolutely infuriates the anti-sprayer activists in the crowd. So be it.
Final bit of advice: if the BS is minor and just occasional, learn to live with it rather than rushing out the spray.
Wishing you good luck in your garden. : )
buford and dublinbay, thank you for the safe way to spray information. That was missing in the first part of this thread but was included in the earlier thread that I linked to.
The following was stated: "We all understand the world and how it works. Politics, corruption, --------. "
H.Kuska comment. I wish the above that everyone understands was true, but unfortunately there appears to still be many people who believe that if the government approved it, it must be safe.
Even if there is no corruption, there is still the time lag of around 5 years that it takes the government to subject an already approved chemical to re-review. That is why I recommend that individuals pay attention to what current research is reporting about a chemical that he/she in considering using and if flags are found utilize the precautionary principle until the government review process is completed.
Unfortunately there is what some will describe as corruption. This is the influence of special interests groups on the review process. The Utah link that I gave above cites the following: "Worse still, in a clear conflict of interest, if not outright corruption, a member of the board of directors of the Utah Pest Control and Lawncare Association, XXXXXX ��" essentially as a lobbyist for pesticide applicators ��" is the XXXXXXXX of UDAF’s pesticide program. It’s like the tobacco companies regulating smoking."
H.Kuska additional comment: at the federal level, you may find the following link of interest.
(Two quotes to tweak your interest.)
" By executive order, OIRA is supposed to review proposed rules within 90 days of receiving them, with the possibility of a single, 30-day extension. That’s four months, maximum.
Why has the chemicals of concern list been at OIRA for three years? No one is saying."
"EPA rules seem to draw extra scrutiny. “EPA receives more sustained attention from OIRA than any other federal agency,” Heinzerling writes. Fifteen of the 22 EPA rules under review have been at OIRA for more than a year."
Here is a link that might be useful: 'Chemicals of Concern' list still wrapped in OMB red tape
This post was edited by henry_kuska on Mon, May 13, 13 at 14:03
dublinbay, I must not be an "anti-sprayer activist" because I find your advice to be very sound and sensible. To me spraying should be a last-ditch effort when other methods have failed, and personally I would take out the roses that are most affected by disease, but then again until this year I didn't have much of a problem with disease. It's up to everyone to weigh having roses against having to spray them to keep them healthy, and for me if I had to spray everything every two weeks in order to keep it in my garden I'd be growing nothing but irises, day lilies and pelargoniums. As has been pointed out, spraying in a private garden is small beer compared to the wholesale spraying that goes on with the foods that we do put in our mouths, and that does worry me more. But that's another subject altogether...
I'm with you, Ingrid. Any rose that needs regular spraying all season long quickly gets the boot in my garden. The first line of defense is planting only those roses that have at least "good" disease-resistance--even better, "very good" to "excellent" disease-resistance. But even the best of roses can be susceptible occasionally to BS, especially in regions with heavy BS pressures--so decisions have to be made. I can accept having to spray a couple times in the spring (heavy BS time) and a couple times in the fall (second heaviest BS time) --but much more than that, and I start looking around for a new home for that rose--in someone else's yard!
I particularly like your statement, Ingrid, that "spraying in a private garden is small beer compared to the wholesale spraying that goes on with the foods that we do put in our mouths, and that does worry me more.
Yes, it is a matter of perspective sometimes, isn't it!
The following was stated: "I particularly like your statement, Ingrid, that "spraying in a private garden is small beer compared to the wholesale spraying that goes on with the foods that we do put in our mouths, and that does worry me more.
Yes, it is a matter of perspective sometimes, isn't it! "
H. Kuska comment: What one sprays in a private garden is what one has to be concerned about regarding personal exposure and exposure to your household members and pets. For example: The following had been stated earlier in this thread by dublinbay z6 KS (My Page) on Mon, May 13, 13 at 13:06: "My practical advice is don't use a fungicide unless it is absolutely necessary; if you need to use it, use it as infrequently as possible while still getting the job done. Take some practical precautions: cover arms and legs, put those clothes in the wash immediately after you finish spraying and take a shower--just to be on the safe side. And spray only when there is very little to no wind (usually earlier in the morning)--you don't want a faceful of spray from stray breezes! Don't eat or smoke while spraying--until you have washed your clothes and body.
It is good to remember that these sprays can cause damage if mis-used, so read directions carefully." End of quote.
I have to laugh. I would like to know how many of us smoke cigarettes while spraying fungicide.
Good grief, why would anyone who smokes cigarettes worry about spraying fungicide? Concerned about experiencing endocrine problems before the lung cancer killed them?
Okay, now back to our regularly scheduled discussion...
Hear, hear, subk3. The main victims of malaria in Africa are children, too. But we never hear about that in the U.S. These deaths are preventable with DDT. Diane
It appears that some people think of experiencing endocrine problems as a one generation problem. However, "Some EDCs produce effects that can cross generations (transgenerational effects), such that exposure of a pregnant woman or wild animal may affect not only the development of her offspring but also their offspring over several generations. This means that the increase in disease rates we are seeing today could in part be due to exposures of our grandparents to EDCs, and these effects could increase over each generation due to both transgenerational transmission of the altered programming and continued exposure across generations."
Here is a link that might be useful: World Health Organization 2012 Report
Perhaps at least half of the readers may be interested in this report presented at the New York Academy of Sciences June 11, 2012.:
Title: "IN VITRO INHIBITION OF BREAST CANCER RESISTANT PROTEIN (BCRP) TRANSPORT ACTIVITY BY ENDOCRINE DISRUPTING CHEMICALS
Author: Qi Wang1
Authors affiliation: 1 Rutgers University, Department of Pharmacology and Toxicology, Piscataway, NJ 2 Joint Graduate Program in Toxicology, Rutgers/UMDNJ, Piscataway, NJ , Kristin M Bircsak1,2, Lauren M Aleksunes1
Abstract: The scientific community has voiced increasing concern regarding disruption of endocrine and reproductive systems as a result of exposure to xenobiotics during pregnancy. These endocrine-disrupting chemicals (EDCs) are diverse and include plasticizers, mycotoxins, phytoestrogens, and pesticides. The breast cancer resistance protein (BCRP) is a chemical efflux transporter expressed in the placenta as well as the developing fetus. Inhibition of the fetoprotective function of BCRP may be a mechanism involved in developmental toxicities following EDC exposure. The purpose of this study was to characterize EDCs as potential substrates and inhibitors of the BCRP transporter. Two in vitro screening assays, the BCRP ATPase assay and inverted membrane vesicle assay, were usedto test interactions between BCRP and twelve chemicals with potential for endocrine disruption: bisphenol A, genistein, methoxychlor, prochloraz, zearalenone, tebuconazole, propiconazole, tributyltin, zeranol, myclobutanil, propargite and epoxiconazole. Based on the ATPase assay, it was confirmed that genistein is a substrate for BCRP, while slight increases in ATP hydrolysis were observed for tributyltin, zeranol, zearalenone and bisphenol A, indicating they may be possible substrates. In both assays, all twelve EDCs inhibited BCRP transport of known substrates. The order of inhibitory potency was genistein> tributyltin> zeranol> zearalenone≌ methoxychlor> tebuconazole> prochloraz≅ propargite> propiconazole> epiconazole> bisphenol A > myclobutanil. Cell-based studies are currently underway to further characterize the inhibitory kinetics of EDCs on BCRP-mediated transport. These findings may assist in risk assessment of perinatal exposure to these chemicals. Supported by ES-005022, DK-080774, ES-020522."
Here is a link that might be useful: link for above
Do you every go out in your garden any more? Or do you just squat by your computer finding all this evil about roses? Aren't you so old you can't even find your endocrines...let enough tell if they've been disrupted. Go pester another hobby and give up roses. You obviously hate them.
Really, all this bashing because someone presents scientific information to keep you better inform. Isn't there a saying, the more you know. You might not agree with him but the information he's providing is not about hating roses or gardening for that matter. But to help you approach it from a safer manner.
I wish there was some way to take most of this poor persons post and have it opened as another post all together. That way if you are interested in what someone has to say about certain products, let them read and post. You know, I've heard for years that "exhibitors run new rose growers off because they try to force people to grow this kind of rose or that type of rose". Good gravy folks. You talk about trying to "stuff" something down someones throat. The one thing I have learned about my hobby is not to discourage new rose growers. ENCORAGE them and answers their questions without stuffing "my way" down their throat. This garbage of taking over a post to promote someones personal feelings about something has got to come to an end. If I was a new rose grower with a question about something and this happened to my post, I'd go somewhere else. There are 29 post to this persons question. How many actually answered the question?? This has turned into a garbage can.
We all very probably have an over 'room temperature' I.Q.
Reading cautions once or twice should arm us with what we need to know.
I am a new rose lover and am trying to get what I need from the many folks on this forum that have great experience. I really don't want to see one million words
on the same subject.
SO ALRIGHT ALREADY, I KNOW NOT TO USE THE BAD SPRAYS OFTEN AND TO TAKE CARE WHEN I DO!
One thing I would caution about using ANY systemic fungicide is that using the same product exclusively for a whole season can encourage development of resistant strains of the fungus. That also applies to products with different chemicals but with the same mode of action(MOA)
If you are going to use a systemic, do it with a strategy that will not encourage resistance. There are many such strategies so you have a choice.
Sympathize with your discovery of blackspot & your efforts to defeat it, Gardenlady48! Here in high rainfall humid central Virginia I've dealt with it, too. My first response is to remove sources of active infection. Snip off the spotted leaves with small scissors, dipping the blades in a jar of plain rubbing (isopropyl) alcohol between cuts to disinfect. (A quart of this alcohol can be found in the first aid section of any store & costs around a dollar. Pour some in a jar large enough to dip the blades of snippers & pruners.) Clean up any fallen leaves as well as those you remove & trash them (do not compost). Notice the location of the spotted leaves. In my garden they often start at the base of the canes. This can be from water splashback off the soil or mulch in heavy rains & humidity higher at the soil line especially if shaded or mulched. If you notice the lower leaves are spotted & have mulch beneath those roses, remove & trash it, too. Wouldn’t replace it until you’re sure the problem is gone. Sometimes the spotted leaves will be further up the canes where they branch. Crowded leafy growth at these junctions can prevent proper drying, light & air circulation to cause ideal conditions for fungal infections such as blackspot. You don’t mention the type of rose or how long they’ve been in your garden. Roses are usually pruned before leaf out to head off this type of growth. If your roses are new to your garden this year, they may not have been pruned this way & it may help to do it selectively now if you find blackspot in this type of location, basically thinning out to admit light & air. Sometimes the new tip growth, being so tender, will succumb to blackspot in excessively rainy weather. Cutting it back to the next set of unblemished leaves & waiting for the temporary weather conditions to pass may be all that’s needed. So what to do depends upon what an investigation reveals.
If these measures prove inadequate, I’ve occasionally sprayed with old-fashioned mixtures like baking soda & non-GMO canola oil or sulpur temporarily. Fungal infections seem highly pH & weather dependent. Haven’t needed to spray anything for years now (knock on wood) so can’t give recommendations without digging up my old notebooks & the garden is calling to me. You might go over to the Organic Rose Growing forum here on GardenWeb & see what they suggest. When spraying had best luck in the early evening after wind & heat died down on a plant already well watered earlier. Fine mist spray applied with one of those long wand extensions that can spray the undersides of leaves as thoroughly as the top & spray the soil surface without disturbing it worked well. Clean the sprayer with soap & water & rinse thoroughly to eliminate any residue that may mix with the next stuff you may use in the sprayer.
On former occasions where blackspot shows up suddenly & all leaves are showing infection, I’ve trimmed off all the leaves & flowers, removed any mulch & sprayed the bare canes & soil beneath the rose. Sometimes this was due to trying a rose in shadier or more crowded conditions than it needed. In those cases they were moved at the same time to sunnier or airier locations, or their neighbors were moved or thinned, or tree branches were trimmed to allow more light & air. A detective response to what might improve the situation & health. This often worked & the new growth was clean. Sometimes it didn’t & sometimes the rose was just young & outgrew its tendency to blackspot as it matured. Often at the end of the growing season with an Indian Summer & excessive rain, even mature roses here will spot a few leaves. I don’t hold it against them & simply remove the affected leaves, tidy the area when they go dormant & have no problems the following season. When a rose continually blackspots & fails to thrive over time even with these measures, it may be a poor specimen as an individual plant & I may try again with the same variety, sometimes successfully & sometimes not. Have learned to hedge my bets by planting (or transplanting) new roses into pots for observation before planting into the garden. Much easier to move a pot than a rose in the ground. Also research roses resistant in the area & shy away from those with poor reports. And buy the healthiest plants I can find to begin with. In early days of rose growing, took a while to realize I was starting with growth-forced plants that didn’t have a good chance of becoming solidly healthy without intentional coddling.
Fungal diseases gain entry into a garden in so many ways, consider it impossible to eliminate. Like the common cold germs everywhere, some exposed come down with it & others don’t at any given time. Like to concentrate efforts on giving the garden what it needs to promote health. Let us know what you find & do to successfully intercede!
Here is a link that might be useful: organic rose growing forum
Just wanted to add to the original poster -
Fungicide is best use as a preventative measure so spraying it now, once the fungus is on the leaves, will not cause those leaves to clear from the blackspot. Many of us who spray (I spray some of my worst roses and don't spray others), start at the beginning of the season before the roses have even leafed out and before the fungus is able to spread, and spray regularly. Also, do not make the same mistake I made originally - sources do suggest to remove infected leaves. On some of my roses, a majority of the leaves get infected. Do not remove a majority of the leaves. Roses need leaves for photosynthesis and removing all of its food making capabilities will stress it more than blackspot. In those cases, I left the leaves be until the rose grew other leaves and the infected ones fell and then cleaned them up.
Tebuconazole (Bayer) ... propiconazole (Banner Maxx) ... everything else that's said is just hysterics, IMHO. They're among the most inoffensive chemicals around. The stuff is even used in shampoos to prevent dandruff - Nizoral (ketaconazole).
Bayer advanced is very effective. Picture has nothing to do with anything. I just like to show off.
This post was edited by susan4952 on Sun, Jun 23, 13 at 23:17