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Blackspot on roses near tree
Does being near or under a tree make blackspot worse? My Kentucky Derby is
always COVERED with blackspot, and no amount of anything will keep it from looking pitiful. The tree is a crabapple, I think. I have 3 other roses under the same tree (it doesn't block their sun) and they all have minor blackspot too, though not as much. I wonder if the tree makes it worse? Or weeds? Does anyone else have a blackspot problem with Kentucky Derby? JimS. Seattle |
Blackspot on roses near tree
"JimS." wrote in message news:kPPBa.1038545$3D1.607580@sccrnsc01... Does being near or under a tree make blackspot worse? My Kentucky Derby is always COVERED with blackspot, and no amount of anything will keep it from looking pitiful. The sun helps to keep the leaves dry, and direct sunlight helps to keep the spores from germinating, so its position in partial shade may have more to do with it than the variety. I don't have that variety, but I have noticed that the roses in *full* sun have noticeably less fungal disease in general, than those who share their sunlight. Scopata Fuori |
Blackspot on roses near tree
On Fri, 30 May 2003 21:12:48 GMT, "JimS."
wrote: Does being near or under a tree make blackspot worse? My Kentucky Derby is always COVERED with blackspot, and no amount of anything will keep it from looking pitiful. The tree is a crabapple, I think. I believe I read somewhere that roses and some fruit trees share the same propensity for fungal diseases. Anyone hear of that? |
Blackspot on roses near tree
Shiva wrote: I believe I read somewhere that roses and some fruit trees share the same propensity for fungal diseases. Anyone hear of that? I've seen some of the same diseases listed, that affect my roses, listed on my fruit tree sprays. But perhaps I have been lucky, or maybe my roses are just much more tasty than my peach or apples, as I have never seen a trace of BS on those. I do get a horrific blight on the peaches, though, that I have yet to conquer, that turns them all into rotten, fly swarmed messes. I'm hoping this year's spray of Messenger and bt will keep it in check. If not, I plan to take a sample into the local county agricultural extension office, for further identification and advice on how to thwart it. Scopata Fuori |
Blackspot on roses near tree
"JimS." wrote Does being near or under a tree make blackspot worse? My Kentucky Derby is always COVERED with blackspot, and no amount of anything will keep it from looking pitiful. The tree is a crabapple, I think. I have 3 other roses under the same tree (it doesn't block their sun) and they all have minor blackspot too, though not as much. I wonder if the tree makes it worse? Or weeds? Does anyone else have a blackspot problem with Kentucky Derby? JimS. Hello Jim, Are you sure it is blackspot and not cercospora? The trees in the park around us have a constant strain of cercospora and naturally everything including our roses are spotted with it. Actually the two roses under our crabapple Brandywine are clean as whistles. Check this link for the cercospora info. http://www.aces.edu/department/extco...5/anr-505.html Allegra |
Blackspot on roses near tree
Hi Allegra,
Nope, it's not cercospora. It's definitely blackspot. I think it's just a problem with that Kentucky Derby. The spotting on the other roses is minor and probably just because I'm not aggressive enough on the fungicides. But the K.D. is almost a lost cause, spotwise. If the spot wasn't so crowded I'd dig it up and plant something else. But considering how crummy a spot it is, I guess I will just live with the spots. At least the blooms are nice. JimS. "Allegra" wrote in message et... "JimS." wrote Does being near or under a tree make blackspot worse? My Kentucky Derby is always COVERED with blackspot, and no amount of anything will keep it from looking pitiful. The tree is a crabapple, I think. I have 3 other roses under the same tree (it doesn't block their sun) and they all have minor blackspot too, though not as much. I wonder if the tree makes it worse? Or weeds? Does anyone else have a blackspot problem with Kentucky Derby? JimS. Hello Jim, Are you sure it is blackspot and not cercospora? The trees in the park around us have a constant strain of cercospora and naturally everything including our roses are spotted with it. Actually the two roses under our crabapple Brandywine are clean as whistles. Check this link for the cercospora info. http://www.aces.edu/department/extco...5/anr-505.html Allegra |
Blackspot on roses near tree
As has been mentioned, good horticultural practices and selelection of
resistant varieites are the best method to minimize black spot and the other fungal diseases. Note that the scientific name of most of the fungal diseases include the word 'rosa' in some form. These diseases are specific to roses and are not transmitted from non-rose plants or trees. Education and prevention are the operative words, good garden sanitation, selection of resistant varities and if necessary a regular preventative spray program will keep your roses healthy and disease free. I have 'shovel pruned' a number of varities over the years, the 'disease magnets' are just not worth keeping. Just my $0.02 worth, Tim |
Blackspot on roses near tree
In article kPPBa.1038545$3D1.607580@sccrnsc01,
says... Does being near or under a tree make blackspot worse? just for lack of sun, yes, absolutely, without a doubt. I grow R. foetida (yes Mabel, my former garden Showpiece and Cornerstone still has one blooming cane) and R. foetida bicolor, both of which are the A-#1 poster children for blackspot, it's where all the spot comes from in Hybrid Teas, etc, matter of fact. R. foetida, full sun 24 hours a day; R. foetida bicolor, a considerable amount of shade. In more than a dozen years I'v never seen blackspot to *any degree on Foetida, but Foetida bicolor jumps at every opportunity. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Blackspot on roses near tree
In article , says...
As has been mentioned, good horticultural practices and selelection of resistant varieites are the best method to minimize black spot and the other fungal diseases. Note that the scientific name of most of the fungal diseases include the word 'rosa' in some form. These diseases are specific to roses and are not transmitted from non-rose plants or trees. amen. an apple tree with blackspot is a scary thing to contemplate. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Blackspot on roses near tree
After Tim Tompkins got finished preaching to us about proper selection techniques that would rule out most if not all of the roses I want to grow here in the swamps, he said: Note that the scientific name of most of the fungal diseases include the word 'rosa' in some form. These diseases are specific to roses and are not transmitted from non-rose plants or trees. This is hairsplitting of the highest degree. The same mold or other fungus spores that cause downy mildew on peach trees causes downy mildew on rose plants. Once on the rose plant, it gets the "rosae" tag, Latin for "of rose" simply because in that particular case it is ON A ROSE PLANT. As for black spot, the fungus Diplocarpon rosae causes black spot in roses. The fungus Diplocarpon earliana causes a similar disease in strawberries. Here is a site that discusses it: http://www.inra.fr/Internet/Produits...ne/6dipear.htm Diplocarpon mespili causes leaf spots in hawthorne trees that result in defoliation. While the disease is referred to as Hawthorn Leaf Blight, its action is the same as that of diplocaron in roses. Here is the Cornell site that discusses this: http://plantclinic.cornell.edu/FactS.../hawblight.htm Therefore, while one may certainly say that apple trees do not get black spot, one may not say that the fungus causing the disease is specific to ROSES. Here is one link that demonstrates that apple and peach trees are subject to thesome of the same fungal diseases as roses. http://www.ca.uky.edu/agcollege/plan...n/homefung.htm Here is another that describes fungal diseases roses and fruit trees sha http://pearl.agcomm.okstate.edu/plan...ses/f-7617.pdf This site discusses anthracnose in trees--we already know it occurs in roses: http://pearl.agcomm.okstate.edu/plan...ses/f-7634.pdf Although certainly not a fruit tree, Dogwoods are quite common around here and are prone to Cercospora leaf spot, just as roses are. This UC Davis site discusses the fungus Sphaerotheca pannosa, which causes powdery mildew, and notes that rosae is one variety of the disease caused by this fungus--the one on roses. http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7463.html What I was remembering was reading that roses and some fruit trees share a propensity for fungal disease--not necessarily black spot, just fungus in general. Apple and Pear trees are susceptible to scab, which is a disease caused by the fungus venturia inaequalis. If you look at the photos on this page: http://www.caf.wvu.edu/kearneysville/wvufarm11.html you will see that apple, cherry, and peach trees suffer from a variety of leaf spot diseases that cause defoliation. While these specific diseases may not travel from the fruit trees to roses, the conditions which would foster fungal disease in fruit trees would also do so in roses. All of the above may be avoided by the regular application of appropriate fungicides. If one is willing to do this, one may grow any rose that strikes one's fancy. I do this and I highly recommend it. |
Blackspot on roses near tree
"Shiva" wrote in message s.com... This is hairsplitting of the highest degree. The same mold or other fungus spores that cause downy mildew on peach trees causes downy mildew on rose plants. Once on the rose plant, it gets the "rosae" tag, Latin for "of rose" simply because in that particular case it is ON A ROSE PLANT. Excellent points. It could well be, that whatever was bothering my roses, was what was eating my fruit trees, although the symptoms may not have been identical. Same disease, different effects. I'm hoping that Messenger gives my fruit trees enough resistance this year to ward off the rotting blight that ruins every last peach. My neighbor came over this afternoon, and commented on how noticeably free of blackspot my roses are, and was impressed by the significant difference in my group of seven Messenger treated mini in pots, vs. the seven controls. I hope this is not a "diminishing returns" sort of thing, where the effects will lessen over time. I don't expect this product to be a "magic bullet," but if it gives my plants enough of a boost so they can fight more of their own battles, that's less chemical warfare I have to wage. I use a modified IPM program, but have had to resort to the Weapons of Fungal Destruction when the determination of the local fungus population overwhelms the care I have taken to provide a fungus-unfriendly habitat. The botrytis outbreak was quickly curbed by the prompt application of the Banner Maxx mixture I sprayed last week. And I hope keeping the rose gardens airy and uncrowded discourages its return anytime soon. Scopata Fuori "Bad cat!" |
Blackspot on roses near tree
lms wrote:
R. foetida, full sun 24 hours a day; Where are you that you get 24 hours of sun? -- Henry |
Blackspot on roses near tree
Where are you that you get 24 hours of sun?
must be up north.... way up north... :) -- be safe. flip ^___^ Count to three. Make a wish. Close your eyes. \^.^/ Wait. Scratch that, reverse it. ==u== - apologies to Roald Dahl |
Blackspot on roses near tree
On Mon, 2 Jun 2003 11:57:50 -0400, Philip Edward Lewis
wrote: Where are you that you get 24 hours of sun? must be up north.... way up north... :) He's from Outer blinking Space. The sun is on the other side of his eyes. Set Number 2. |
Blackspot on roses near tree
On Sun, 1 Jun 2003 18:00:11 -0400, "Scopata Fuori"
wrote: Excellent points. It could well be, that whatever was bothering my roses, was what was eating my fruit trees, although the symptoms may not have been identical. Same disease, different effects. I'm hoping that Messenger gives my fruit trees enough resistance this year to ward off the rotting blight that ruins every last peach. So that is what Messenger is for. I'll have to look into it. |
Blackspot on roses near tree
Henry wrote:
lms wrote: R. foetida, full sun 24 hours a day; Where are you that you get 24 hours of sun? May be it is a perk from his employers, since he works at a radioastronomy laboratory ;-). -- Radika California USDA 9 / Sunset 15 |
Blackspot on roses near tree
"Shiva" wrote in message So that is what Messenger is for. I'll have to look into it. Take a look at my pictures on the Imagestation site. The difference is unmistakable. I am a skeptic, and it takes a whole lot of convincing, with hard, reproducible facts, and unquestionably obvious results, to persuade me of anything, especially something intangible. See for yourself. Group 1, is the treated group of seven minis. The picture of three from the top down, are the smallest three from each group. The other photos, are of some of the others in my gardens. They were all sprayed with Messenger once, and just the seven minis int he control group didn't get it. I sprayed it again last weekend, but it rained yet again unexpectedly, so I may have to reapply it. The relative absence of blackspot is nothing short of a miracle, as much rain as I have had. I did get a round of botrytis, but a spray of Banner Maxx took care of that, and they rebounded beautifully. I am still counting buds and basal breaks on the seven controls vs. seven treated minis, to ensure this was not just a fluke. But they are so obviously healthier that it doesn't take a close look to see the difference. http://www.imagestation.com/album/?id=4290061763 Scopata Fuori "Bad cat!" |
Blackspot on roses near tree
In article 3edb533c$0$6974$afc38c87@, lid says...
lms wrote: In article , says... Note that the scientific name of most of the fungal diseases include the word 'rosa' in some form. These diseases are specific to roses and are not transmitted from non-rose plants or trees. amen. an apple tree with blackspot is a scary thing to contemplate. Apple black spot (a.k.a. Apple Scab) is the most important disease of apples and is caused by the fungus Venturia inaequalis. It is a different but similar fungus (Diplocarpon rosae) than the one that causes black spot in roses. The conditions for spread and outbreaks of the two types of black spot are similar, however so if you have both apples and roses, a bad season for black spot on one will probably be a bad season for the other, as well. good info Henry but the fact is I've seen the willing roses defoliate quite the number of times, though certainly not every year, but I've never had any similar problems with apples. With apples, I either get 10,000 or I get the big zero, plus or minus a few hundred, this year it's the latter. I've never seen any of them do anything but blot out the sun entirely, I've lost an Olds mobile out there. In both cases, primary infection (when your plants get the disease) is caused by mainly by ascospores. Ascospores are one of two types of spores produced by the fungus during their life cycle. In the spring, ascospores are released from infected leaves or canes, often those that have fallen to the ground the previous season. For the spores to infect healthy leaves, the leaves must be continually wet for several hours, the relative humidity high, and the temperature around 68F to 75F. Here is the east, that's a common enough situation and pretty much describes standard spring weather. In New Mexico, I expect black spot is all but rumor. That's one to remember and is fairly accurate, although there are two times of the year it happens--one's an exception (El Nino[a]) and the other's the rule (fall) maybe a little less than half the time. By this time it's way too late to even worry about, the freezes come. A few years back with El Nino, the monsoon started and never stopped. For a couple years after that things were weird, I began to question what was normal. The last couple/three have been dry dry, even Tropicana keeps its leaves. One thing is for certain, even if you live in Saudi Arabia--Soleil d'Or, the mother of all yellow Hybrid Teas, will blackspot in the fall. Once infected, it's pretty much impossible to "cure" black spot so preventing infection is your only real alternative (well, I suppose living with it is another available option). Most roses just get ugly when they blackspot--and face it, a hybrid tea rose's mid-summer foliage in the best of cases usually ain't nothin to write home about--but Soleil d'Or's behavior is a real study in how much roses really care whether they spot or not. As soon as the leaves are gone--basically all at once--it erupts in this spring-green color all over, just literally busts out in new growth. hahahaha, then it freezes, bye bye. Worrying about blackspot is strictly a human thing, I don't think it plays much lead in the list of life cycle determinants. And if all the leaves are gone, it's just 'damn roses' and ThankGod for buddleia and pecan crops and naked ladies. The susceptibility of different roses varies quite a bit. There are also different races of this pathogen and a rose that seems to be resistant in one region may be damaged in another. Applications (often repeated) of fungicide will certainly help. It's also important to get rid of infected tissue (leaves and canes). Don't just throw them on the compost or you'll be storing up spores for next year. It's actually best to burn them but of course that's not allowed for many of us in the suburbs. A large supply of last year's infected leaves can lead to infection even when the conditions are less then ideal (from the fungus' perspective). hey man, I've made an incoherent career outa pounding two-headed frog makers, and it's all just ****ing in the wind, one way or the other. Might as well be talking about abortion. I think all the sprayers live in Scarborough Country. In any case I think all this should be 'don't ask, don't tell', but that would never work, this is a rose group for godsake. Right after we learn the word rose we learn the word spray and as long as there are high centered roses and new austin introductions there will be people chained to this rut. Save the spray for the hordes of locusts. And my avocados for godsake. I burn dead canes cause I'm too lazy and don't want needle holes in all my fingers after a few hours. But for me mulch is mulch, you definitely know I've never worried about dormant little spores. m -- Henry -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
Blackspot on roses near tree
In article m,
says... On Mon, 2 Jun 2003 11:57:50 -0400, Philip Edward Lewis wrote: Where are you that you get 24 hours of sun? must be up north.... way up north... :) He's from Outer blinking Space. The sun is on the other side of his eyes. Set Number 2. I don't quite unnerstand this but I kinda like it, strangely enough. m -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
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