Rose diesease ?? fungus problem ??

gosar(z9 CA)May 9, 2003

I am a newbie in delaing with roses except for the fact that i cut them in the fall to 1 feet height...a.nd then applied the Rose n feed in March 1st week of this year. I am in the Bay Area , CA. My questions are :

For some reason, there is white fungus (i think) which is developing on the leaves of the roses as well as at the bottom of the petals. Ii is not allowing the rosees to grow...What is this disease ?? How to take care of this ?? Any pesticide, etc ?? An Organic remedy will be super. I have like 5 rose plants in the front-year. How do i avoid it spreading ?? How do i avoid it completely ?

What do you use for Fertilizer for Roses. Apart from Corn Meal...what other organic fertilizer are there ?? since i am not able to find corn meal here (except for the one which is in grocery store)

Please help.

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There should be plenty of corn meal, mesa, in California. It's what tortillas are made of.

    Bookmark   May 12, 2003 at 1:27AM
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Your fungus is probably powdery mildew. I don't get that on my roses, so I am not sure exactly what to do about it.

Fertilizer-- get alfalfa pellets or alfalfa meal from a feed supply store. Don't get the kind with added sugar-- rabbit food. Cottonseed meal is also good if you can find it. Also plenty of composted manure.

There is a lot of debate as to whether corn meal is effective, but the kind you get at the grocery store is fine. Just make sure it's plain cornmeal and not "cornbread mix."

    Bookmark   May 12, 2003 at 3:29PM
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Your Roses will thrive if you put some banana peels around the bottom of the rose. Saw this in a gardener's book. I also noticed that coffee ground is very beneficial.

    Bookmark   February 3, 2004 at 7:24PM
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LizzieA(z9 CA Sunset 17)

As one who lives in the Bay Area and attempts to grow a few roses, I can confidently say the white stuff you have is powdery mildew! I think Safer's Fungicide is considered organic, since it's just sulphur and it is supposed to control powdery mildew and rust, the two Bay Area banes of our roses' existence. Just keep spraying it per the instructions. Cornell mixture (2 Tbs Sunspray oil and 1 Tbs baking soda in 1 gal water) is supposed to be a blackspot and mildew prophylactic, but doesn't seem to do much on existing disease, plus you shouldn't use it with the fungicide, it burns the leaves, so it's either/or.

Corn Meal is also considered both a fungicide and a fertilizer and is in every grocery store under the name Polenta, just scratch it in around the rose bushes but it won't do anything to cure disease once it's there, again more of a prophylactic. If you have any of the Whole Food stores or the Rainbow or Berkeley Bowl-type stores around, they sell cornmeal loose by the lb for about 49cents/lb.

Alaflfa pellets can be found in some of the good nurseries some sell it just in small bags (boxed E.B. White's is the most expensive) Some pet food stores also carry it. I was lucky and found a feed store that carries 50lb bags for $10, but that was in the 'burbs. Sprinkle 1 cup around the bottom of each rose bush. Worm Castings (WormGold) is also really good for all plants, but again, expensive unless you make your own (see the Vermiculture Forum)

Try the Organic Gardening forum FAQs for other organic fertilizers, there's a lot of them.

    Bookmark   February 4, 2004 at 2:46PM
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steveandjoy(z10 BGI)

I too am a newcomer to growing roses and wish to do so organically. I notice that there is reference to corn meal as a fungicide. Please explain how this works. Thanks

    Bookmark   February 27, 2004 at 7:49PM
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LizzieA(z9 CA Sunset 17)

If you do a search on 'cornmeal fungicide' for the entire site, you'll find everything on the subject that's on GardenWeb - like this one:
From a post from DScall in Austin, TX.

This is what Texas A&M University says about corn meal...
Biological Control of Soilborne Fungi
It is known that certain fungal species in the genus Trichoderma feed on mycelium and sclerotia of Sclerotinia minor. Sclerotium rolfsii and Rhizoctonia sp. All peanut fields in Texas tested to date have a natural population of Trichoderma. For several years, tests have been conducted in Texas using corn meal to stimulate Trichoderma development as a way to control the major soilborne disease fungi. When yellow corn meal is applied to fields in the presence of moist surface soil, Trichoderma builds up very rapidly over a 5 to 10 day period. The resulting high Trichoderma population can destroy vast amounts of Sclerotinia, Sclerotium and Rhizoctonia. This enhanced, natural biological control process is almost identical to the processes that occur when crop rotation is practiced. The level of control with corn meal is influenced by: 1) organic matter source 2) soil moisture, 3) temperature, and 4) pesticides used. Seasonal applications of certain fungicides may inhibit Trichoderma. Testing will continue to determine the rates and application methods that will give consistent, economical control.

Here's the link to the whole article...

2002 Peanut Disease and Nematode Control Recommendations

Our local (San Antonio) organic gardeners are reporting that corn meal is working for many more fungi (including toenail fungus). A few (very few) ranchers and vets are reporting on the use of corn meal spilled into horse and cattle bedding to reduce the time leg wounds take to heal.

    Bookmark   February 27, 2004 at 8:29PM
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steveandjoy(z10 BGI)

Thanks LizzieA.

    Bookmark   February 29, 2004 at 9:35PM
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gosar(z9 CA)

Lizzie A,

can you let me knwo where did you find Alfalfa pellets in the suburbs ? Can you find polenta in Safeway/Albertson/Raleigh's ?? Is polenta a brand name...
I went to safeway but noone knows what a polenta is !!
Any help appreciated.
The corn flour which you get at grocery stores is bleached
which i beleive should not be used.

    Bookmark   April 7, 2004 at 2:24PM
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Hey guys, I'm from the SF Bay Area. I found alfalfa pellets 'for roses' at a hardware store. They also had them for rabbits, but they delineated the difference. Call around. As to cornmeal, the cheapest I've found so far is at Berkeley Bowl in bulk, 49 cents a pound. You can also get it at Safeway or Albertson's. I "think" that it cost 5.99 for a five pound bag. "Albers" brand. Look in the dry goods area (spices, four, etc.) The top of the bag is dark blue and the body of the bag is orange with yellow writing. Has some B vitamins in it too, but that shouldn't be an issue. No other ingredients. More expensive, but easier to get.

I'd just check out some natural food stores. I also found some at a tiny produce market nearby.

And btw, with ALL of the places that I've mentioned, it's NOT corn flour, it's corn meal. In the bins, just look at it. If it's coasely ground and doesn't have anything else in it, it's what you want.

This is supposedly good for your lawn too. I bought about 25 pounds of it and did my roses, my flowerbeds and my lawn. What the hey! Can't hurt, might help.

    Bookmark   May 16, 2004 at 6:02PM
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Btw, the stuff at Berkeley Bowl is organic if that is an issue for you.

If I lived closer to it, that is where I would get all of it. The bin is much bigger than other other bulk place that I've seen thus far, so you can get a lot of it at one time.

    Bookmark   May 16, 2004 at 6:04PM
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LizzieA(z9 CA Sunset 17)

I found the feed store where I purchsed the alfalfa out in Pleasant Hill/Concord area (actually I can't remember the name of the place) but you can find it in small quantities in some ACE-type hardware stores that have garden supplies but it is expensive there. Our local one carries it at $4.00 for 5lb!! Polenta is not a brand name and they should have heard of it, it's in our Safeway and Albertsons, it's the same thing as corn meal, just ground a little coarser. Either will do although cornmeal is probably cheaper. I sprinkle a handful of both it and alfalfa around the rose and water it in.

For fungus, which is where this thread started, I've found that Safer's Fungicide is probably the easiest and most organic thing to use to try to get rid of it but you must spray regularly. In this area, I don't think you can keep PM (powdery mildew) away no matter what you do, but it does seem less prevalent and less able to get a damaging foothold if the rose is healthy.

Also, some people think that spraying the rose with water helps get rid of the fungus spores, just don't spray the roses' foliage at night, if you spray the plant, do it in the morning only.

    Bookmark   May 17, 2004 at 12:39PM
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Neither banana peals, corn meal, alfalfa meal, nor anything else you put on the soil will get rid of or prevent powdery mildew on roses. You must spray with a fungicide proven to kill powdery mildew. For an organic gardener, the two best choices are a 10% milk-in-water solution or the Cornell formula (2 Tbsp of horticultural oil and 1 heaping Tbsp of baking soda in a gallon of water). Both will work, but the Cornell formula is more effective and immediate than the milk spray.

    Bookmark   May 17, 2004 at 4:53PM
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As I have been the one promoting the use of cornmeal as a plant fungicide let me add a few thoughts to this discussion. From my own trials and notes received from all over the country it is apparent that cornmeal does not control fungus/blackspot on roses or the various tomato problems. However, if you are fighting other types of plant fungus in your garden or lawn, cormeal should be tried as a fungicide. We are finding it very useful for a number of problems.

THE FOLLOWING IS IMPORTANT! Any treatment, organic or otherwise, aimed at preventing/controlling rose mildew and blackspot must be started early in the spring just as the rose buds begin to swell to be effective. If our CA. friends will begin treating for their mildew problems early in the season they should be able to stay ahead of the mildew. This method also applies to any other plant fungus that troubles you annually. Begin your treatment early with the Cornell formula, or cormeal or copper sprays; whatever treatment you plan to use for a particular plant problem. Beginning treatment early in the season is the key to success for many of the stubborn plant fungi that plague mature plants. Do not use cornmeal on young seedlings until they have developed four sets of new leaves.

    Bookmark   May 22, 2004 at 10:33PM
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Can you help? Is this some kind of a fungus?

Here is a link that might be useful: Visit my garden

    Bookmark   July 5, 2009 at 4:16PM
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I am thrilled and want to give each of you a huge HUG (gosar and SteveandJoy)! for going the organic way... having said that,

I too am a Greencure organics user, but I AGREE! that it has to be done as soon! as you get your first leaves (March/April)otherwise it can be a huge uphill battle, very difficult to have any effect once the fungus rears its ugly head...And you have to apply your organics fungicide very! frequently as much as once a day in certain instances (like with rain or an infested rose)... I had a stray abandoned, unidentifiable mini rose that I did not apply any! fungicide to for several months because I thought it'd end up as a Dr. Huey rootstock...That mini was peppered with BS... I peeled back several leaves, stripping most of the leaves to bare stems, now it seems its new leaves so far look pristine (it has several large clusters now-thanks to my Gardenville sea tea), but it has! taken at least 3 weeks for anything to even out in terms of BS control and I did have to increase the dosage and basically strip the plant bone dry...

Alfalfa pellets I hear are terrific for encouraging basal breaks, and I have heard several stories about coffee grinds sprinkled above ground and banana peel at the bottom of the planting hole...

But for me, time is of the essence so I just resort to my Gardenville sea tea because it seems to combine the best of the best... it contains fish emulsion, compost tea, and seaweed (contains all these nutritional "goodies")...

Another great fungicide I hear about is Serenade...haven't tried it yet, but I will let you know the result when it becomes available at my nursery...

    Bookmark   July 9, 2009 at 2:56PM
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