Orange spots on raspberry leaves

Discussion in 'Garden Pest Management and Identification' started by spike, May 16, 2009.

  1. spike

    spike Member

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    I have orange spots on the top of my raspberry leaves. The problem seems to be worse on the lower leaves, but it affects high and low. I did some web searching and... orange rust doesn't seem to affect red raspberries, only black, and it also affects the underneath of the leaves; yellow rust also seems to primarily affect the underneath of the leaves.

    These orange spots seem to be rings, about 1 mm. in diameter (see photos).

    I have had the same bed for several years with no problems. Last year, I purchased one cane from a nursery. No obvious problems last year, but perhaps this disease came in on that one cane?

    Any suggestions as to the disease or the cure?

    Thanks,

    Sarah
     

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  2. jimweed

    jimweed Active Member

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    Very unusual fungus there. It would be interesting to see what the pathologists at the Ag. center in Abbotsford have to say. It cost $17 to have a sample diagnosed.
     
  3. spike

    spike Member

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    Thanks for the info. Do you know of any other way of getting it to Abbotsford other than driving it myself? (Do they have satellite offices, for example?)

    Sarah
     
  4. jimweed

    jimweed Active Member

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    As far as I know you would have to take the sample out to Abbotsford. I am not aware of any satellite offices. I am sure there could be the possibility of courier, visa, downloading and faxing the request form. The people out there at the Ag. center are very nice and extremely helpful. And they actually have a human who answers the phone.

    You could blue page the telephone number and call them. Ministry of Agriculture, Plant and animal sciences, Delair Rd. Abbotsford. Jim:)
     
  5. C.Wick

    C.Wick Active Member

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    Heya...I just opened this to see the interesting orange spots? Is there a way you can email me a close up of this? I'm thinking we have a similiar issue here. Have you noticed this at all on other plants?
     
  6. spike

    spike Member

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    Yes, it's on all my plants (about 10 feet of canes). I would say it's been about 4 weeks since I first noticed the fungus, if that's what it is. However, I don't think the infestation has gotten worse since my post. Also, it is worse in one area and better in another (the "better" area has the stronger canes and is also farthest from my one new purchased cane from last year). The fungus seems to be drying out a little/going to "dust" (second photo) and not spreading further. I don't really see the affected leaves being harmed, although they might be shriveling a little and also drying out a little (third photo). (I expect the leaves to be more affected soon...) I have had the leaves on one cane all wilt and die, and it was affected with this fungus, but I'm not sure if the fungus was the cause, as other affected canes have not done this.

    I'm not sure the attached photos are closer-up, but that's about as close as I can do!

    I did dig out all the spreading roots with the new shoots about 2 months ago, so I moved all those pots with their new canes to the front yard just last week, and they don't seem to have the fungus. This may be next year's crop?!
     

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    Last edited: May 22, 2009
  7. spike

    spike Member

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    I just reread the last post where you asked if I had noticed the orange spots on other plants. I took that to mean other canes, which I have, but I haven't noticed it on other plants - i.e. other than raspberries...
     
  8. C.Wick

    C.Wick Active Member

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    A possibility here is Orange Rust Fungus. It seems to especially like moist humid areas that have thorny plants, especially roses and berry producing bushes.
    A link I found about it tells a way to help get rid of it and clear it out?
    http://www.ehow.com/how_3036_detect-prevent-rust.html
    Let me keep checking to see if there's any other possibilities here. I was originally going for a type of slime mould? But....
     
  9. spike

    spike Member

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    Not that I know anything about the subject, but based on my web searching, I don't think it's orange rust, for a number of reasons - from my reading, it seems orange rust affects black rasps, not red. Primarily, however, rust affects the underneaths of the leaves, and my fungus is on top. Also, the images of orange rust don't seem to fit exactly... See http://images.google.ca/images?q=or...ent=firefox-a&um=1&ie=UTF-8&sa=N&hl=en&tab=wi

    ?

    Do you have this same thing on other plants?
     
  10. C.Wick

    C.Wick Active Member

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    Oops...lets try maybe Yellow Rust instead?


    plant-disease.ippc.orst.edu/disease.cfm?RecordID=959


    Sorry for the un-clickable link there...Haven't figured out how to put them in here to click on yet.
    But this one is found up North in Washington/Oregon areas so maybe closer to you? The spots appear on the topsides also.
    In my area the spots are underneath so is more likely the Orange Rust. Theres several kinds unfortunately so is hard to place a specific one for me.
     
  11. spike

    spike Member

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    I had considered and discarded yellow rust as a possibility, but your link makes it look more likely than I had thought. I'll try to do some more searching on this...

    Thanks!
     
  12. C.Wick

    C.Wick Active Member

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    I was just telling someone yesterday that it's too bad you can't just type in 'It looks like this, found in this location, found on this date, smells like this, blahblah'...and the answear comes back instantly. :o)
    Hope this helps a bit and you can save you're plants. Raspberries and blueberries are such great fruits to have!
     
  13. Margaret

    Margaret Active Member 10 Years

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    Here on the Sunshine Coast I have got the same thing on the upper side of a couple of red raspberry leaves both of which are low down on the plant. The plant is in an open area which is not particularly wet and I haven't noticed it on any of the roses. I hope that if I cut them off and put them into a sealed garbage bag it may not spread but that may only be an optimistic hope? We are in for a spell of dry weather and hopefully this may stop the spots? Suppose that until we know what it is it is impossible to say if it will damage the fruiting capacity?
    Margaret
     
  14. spike

    spike Member

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    Just an update on the yellow rust possibility. It seems that there is something called "yellow rust" (which I think is what I have, caused by the fungus Phragmidium rubi-idaei) and something else called "late yellow rust" (caused by the fungus Pucciniastrum americanum).

    (Even after reading all of this, I'm not yet sure how I'm going to deal with my yellow rust, so any suggestions would be helpful. I'm going to do some more web searching to try to determine how aggressive I should be on the treatment...)

    Perhaps most helpful is the BC Gov't poster on Raspberry problems. Their photo of yellow rust looks like mine:

    http://www.agf.gov.bc.ca/cropprot/raspberry_ipm_poster.pdf

    Somewhat hopefully, they categorize it as a "leaf disorder". Unfortunately, they don't tell us what to do about it.

    *****

    From http://www.ipm.ucdavis.edu/PMG/r71101111.html

    Yellow Rust
    Pathogen: Phragmidium rubi-idaei

    SYMPTOMS

    Of the major caneberry crops, yellow rust infects only red raspberry and is not a systemic pathogen, meaning the pathogen does not spread internally through the plant. In spring, yellowish orange pustules (aecia) form on the tops of raspberry leaves close to the ground. Aecia occurring early on the tops of the leaves is a general way to distiguish this rust from late leaf rust, which also infects red raspberry.

    Severely affected leaves can dry out and die. Later in June and July, orange to yellow pustules (uredinia) appear on the undersides of leaves; these structures later darken as black teliospores develop from the middle of July to fall. The yellow rust fungus overwinters as teliospores on the bark of remaining floricanes (fruiting canes). Such canes are the sources of inoculum that affect emerging leaves and primocanes (vegetative canes) the following spring.

    MANAGEMENT

    If possible and horticulturally sensible, complete removal of floricane and first flush of primocane is useful in controlling this disease, as it removes most sources of innoculum. Any method of pruning that improves air circulation is helpful in reducing yellow rust, as this allows leaves, flowers, and fruit to dry more quickly, subsequently reducing plant susceptibility.

    Organically Acceptable Methods
    Cultivating to bury old crop debris, removal of fruiting canes after harvest, and sprays of lime sulfur or some fixed copper products are acceptable methods in an organically certified crop.

    (more information at the site about pesticide usage)

    *****

    From http://plant-disease.ippc.orst.edu/disease.cfm?RecordID=959

    Cause: Phragmidium rubi-idaei, a fungus widespread in red raspberry in western Oregon and Washington, particularly in years when spring rains continue late. ...

    Symptoms: Leaf infections in spring and early summer create a yellowish spotting on the upper leaf surface. At first the spots are very small, yellow to orange and slightly raised (spermagonia) but then new, yellow to orangish spore bearing structures (aecia) are produced in a ring around these spots. By summer, another yellow spore stage (uredinia) appears on the lower leaf surface. Some of these structures could be described as orangish without a good comparison. Fruit often dies on the canes before maturing if leaves on fruiting laterals are attacked early in the summer. By harvest, black overwintering spores (teliospores) appear in the yellow uredinia on the lower leaf surface. All succulent plant parts are subject to infection, but cane lesions rarely are observed. Infected canes often are brittle and may break off when old fruiting canes are pruned out.
     
  15. Liz

    Liz Well-Known Member 10 Years

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  16. jimweed

    jimweed Active Member

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    Awesome Spike. Finding that photo on the poster was a good hit.

    Since it can effect the fruit are you going to try a mild copper spray now to see if it slows down the spread?

    Jim.
     
  17. spike

    spike Member

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    Don't know what to do! Never sprayed anything on anything! Where do I find copper spray?
     
  18. jimweed

    jimweed Active Member

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    You should be able to purchase a small container (250g-500g) of powdered copper at a nursery or hardware store. Pick up a 2 gallon plastic watering can as well. You mentioned you only have 10 plants, it is just as easy to just water them down with a copper mix.

    Use the label for directions. A light mixture is best, like 1/2 rate from the label this time of year. Copper can burn the leaves if it is too strongly mixed.

    Keep doing your research and reading though, see if a copper spray this time of year will help the spread. Likely will though. Then prepare for controlling this fungus over next winter.

    all the best, jim.
     
  19. spike

    spike Member

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    Thanks very much! I'll report back...
     
  20. spike

    spike Member

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    So, I've done a bit more googling about yellow rust on raspberries for what steps to take, now that I believe I have yellow rust. I have copied the most pertinent excerpts, below. My conclusions are that I am going to do the following (in chronological order, starting from late spring (i.e. now)):

    => cut off leaves, on an ongoing basis, that have a significant amount of yellow rust (I'm not going to kill myself to do this, just going to do my best); dispose of leaves in the garbage
    => if I can bear it, I may try to thin out my canes to promote the drying of leaves and improve air circulation
    => remove and dispose of old fruiting canes as soon after harvest as possible by cutting them flush to the ground
    => strip leaves from the primocanes (this year's new canes) before they fall off
    => in the fall, remove all fallen leaves and put down a thin layer of composted mulch to try to cover the old cane stubs

    I'm not going to do anything fungicidal at this point; Oregon estimates that without fungicides, it would have a 25% reduction in its crop; at this point, I'm willing to live with that.

    ****************
    - http://www.calstrawberry.com/fileData/docs/Archive_2.3.05_presentation5_bolda_mtg.pdf

    from a presentation on Rust Diseases of Caneberries by Mark Bolda
    UCCE Farm Advisor, Strawberries and Caneberries
    Santa Cruz, Monterey and San Benito Counties

    "Control of Yellow Rust
    •Infests only red raspberry and is not a systemic pathogen. Not systemic.
    •Complete removal of infested cane.
    •Any method of pruning which improves air circulation.
    •Fungicides: fixed copper (Kocide), Rally and Pristine."

    - in his presentation, he evaluates the fungicides and concludes that a combination of Rally & Pristine is best

    ***************

    - http://www.ipmcenters.org/cropprofiles/docs/orraspberries.pdf

    "The major diseases in Oregon raspberries are Botrytis fruit rot, Phytophthora root rot, and yellow rust. Minor diseases include cane blight, spur blight, and Verticillium wilt (9).
    In the spring of 1998, a sudden and widespread outbreak of yellow rust infected Willamette Valley raspberries. The rust infected cultivars that previously had been resistant. Warm, wet weather intensified the outbreak (14)."

    "Growers obtained an emergency exemption to apply propiconazole (Orbit) fungicide to help control the 1998 yellow rust outbreak (14)."

    "Alternatives:
    Ferbam (Carbamate) treatment for yellow rust was only 20% as effective as propiconazole (Orbit) spray (14)."

    "Cultural controls:
    Specialists recommend several cultural control methods to control yellow rust (14):
    ● Cultivate as soon as the weather permits in late fall or early spring to cover fallen leaves, old cane stubs, and refuse and
    thus eliminate infection sources
    ● Remove and burn old fruiting canes as soon after harvest as possible by cutting them flush to the ground
    ● Strip leaves from primocanes before tying
    ● Trellis primocanes when the leaves are off."

    ***************

    - from http://www.croplifefoundation.org/D...s/Prelim Results/Web Raspberries 10-20-04.pdf

    "The Value of Fungicides in U.S. Raspberry Production: Preliminary Findings
    October, 2004"

    "Yellow Rust
    The fungus overwinters in the bark of floricanes, where up to 400 spores per square centimeter have been recorded.[197] Yellow rust is widespread in most raspberry fields, particularly in years when spring rains continue late.[200] The first symptom of yellow rust is the development of orange-yellow pustules on the upper surfaces of leaves. Severely infected leaves turn yellow and drop. Fruit often dies on the canes before maturing if leaves on fruiting laterals are infected early in the summer.[200] The pustules contain numerous spores which are carried about by wind currents or splashing raindrops, which can propagate new infections all summer. In favorable weather, all the plants in a field can become infected.[208]

    Due to a shift towards wet and mild conditions in the Pacific Northwest weather cycle, yellow rust has been appearing earlier in the season and has been spreading more rapidly than before.[201] The shift in weather patterns has also enabled spore stages that did not normally overwinter to do so in the last few mild winters.

    In the Spring of 1998, a sudden and widespread outbreak of yellow rust infected
    Willamette Valley raspberries. The rust infected cultivars had previously been resistant to the disease.[198] “Meeker, “ the most widely-planted cultivar in the Pacific Northwest is normally slow to develop rust symptoms . However, yellow rust is appearing in fields of “Meeker†and the disease is developing quickly.[201] The State of Oregon estimated that without fungicide use yellow rust would lower raspberry yields 25% statewide.[201]

    Research has shown that fungicide applications provide 98-100% control of yellow
    rust.[201]"

    **************

    - see also http://plant-disease.ippc.orst.edu/disease.cfm?RecordID=959

    (I've run out of room in this post; mostly info. about fungicides)

    *****************

    - from http://bulk.resource.org/gpo.gov/register/1999/1999_2996.pdf

    Yellow rust of raspberry is caused by a fungal pathogen, Phragmidium rubiidaei.
    The pathogen is widespread in red raspberry fields in Oregon and Washington States, particularly in years when spring rains continue late. Historically, yellow rust has not been a problem. Under normal winter weather conditions of the Pacific Northwestern United States, teliospores of the pathogen are the sole survivor and they do not infect raspberry plants directly; urediniospores cause most damage to raspberry plants. However, last winter urediniospores also overwintered due to mild winter weather conditions. Urediniospores infected raspberry plants and disease symptoms were seen during early spring season.
    Urediniospores are the most damaging stage of yellow rust because they are
    normally produced in repeating cycles during summer months, but this spring
    they provided an immediate means to cause a rapid buildup of the pathogen,
    resulting in damage that caused this emergency. In addition, during the 1998
    spring season the climatic conditions were very conducive for the disease
    development. The warm weather accompanied by rain caused the plants
    to break bud about 2–3 weeks earlier than normal. The moisture from dew
    and fog were sufficient to allow both spore germination and infection. All of
    these conditions contributed to the current emergency situation. EPA has
    authorized under FIFRA section 18 the use of propiconazole on blueberries for
    control of mummy berry disease (Monilinia vacinii-corymbosi) in Georgia, Maine and South Carolina and the use on raspberries for control of yellow rust (Phragmidium rubi-idaei) in Oregon and Washington. After having reviewed the submissions, EPA concurs that emergency conditions exist for these states.

    ***************

    - from http://www.teagasc.ie/publications/fruit2000/paper6.asp

    Fungal Diseases of Raspberries and Related Crops

    B. Williamson, Scottish Crop Research Institute, Dundee.

    Raspberries and related fruit crops are subjected to infection by many fungal diseases that severely affect growth, survival or productivity. These diseases are particularly serious in regions with poorly drained soils, frequent rainfall and high humidity. The perennial nature of the plant with a biennial cane growth cycle leads to a build-up of fungal inoculum within the plantations over its 8 to 12-year life-span. It is therefore important to obtain healthy stock for planting on disease-free, well-drained soils and to identify fungal pathogens at an early stage to delay the on-set of serious fungal attacks.

    Raspberry root rot (Phytophthora fragaria var. rubi) can be avoided by having soils tested for the pathogen before planting and only planting canes derived from root rot-tested stocks. Once introduced into a field, this fungus cannot be eradicated and only by continued 6-monthly applications of fungicides to soils can this disease be alleviated. Cane spot (Elsinoe veneta), a disease affecting all parts of the plant above soil level, can be particularly serious under Irish conditions. Spur blight (Didymella applanata) and cane botrytis (Botrytis cinerea) affect the emergence of lateral shoots in the season following infection of mature leaves. The latter pathogen, well known as the cause of grey mould disease of fruit, survives in the over-wintering canes and generates inoculum from sclerotia for subsequent infection of flowers and berries. Leptosphaeria coniothyrium, the cause of cane blight, is a common soil fungus that attacks young canes wounded during the growing season mainly by harvesting operations. This fungus is also one of several others that infect young canes at sites damaged specifically by the larvae of the raspberry cane midge (Resseliella theobaldi) resulting in the cane disease complex termed 'midge blight'. Other foliar and fruit diseases, such as powdery mildew (Sphaerotheca macularis), downy mildew (Peronospora rubi) and raspberry yellow rust (Phragmidium rubi) are also more serious under humid conditions.

    All these pathogens can be reduced in importance by maintaining a high standard of crop husbandry. The aim should be to increase soil drainage and the movement of air through the crop canopy to hasten drying of foliage, flowers and berries after dew or rain. Therefore, the control of cane number and density by rigorous pruning, coupled with high standards in weed control are essential features of an effective control strategy.
     
  21. Liz

    Liz Well-Known Member 10 Years

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    Good research. I have not tried them again since they nicked off on me about 15 yrs ago. The trouble is that the soil is ideal here along with the weather. Was a big fruit growing area including canes many years ago. I think if I do it again I will do root barriers OR grow them in a paddock annex so I can use the goats to keep runnaways under control. Bit like they do with the blackberries. Good luck with your crop

    Liz
     

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