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New to forum. Not new to blackspot.

Posted by bluedog 6B/7A (My Page) on
Wed, Mar 22, 06 at 20:10

Hi everyone. Just want to say "hi" from Shrewsbury (exit 109)

My first question of the gardening year, spring having started yesterday, is what can I do now to try to keep the dreaded blackspot from coming back on my roses. Last year I tried to manage it organically with meticulous pruning, compost spraying... I'm willing to continue doing these things but need a better plan.

While we're at it, those hormone traps and soapy water buckets seem pretty wimpy against the japanese beetles. Any advice?


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RE: New to forum. Not new to blackspot.

Knowing what types or roses and how many that you have would help.

You have two options as far as blackspot is concerned, the first is to treat them with a fungicide and the second is to dig your old ones up and plant disease-resistant roses. The "organic" remedies don't work here for blackspot. Powdery mildew, yes, blackspot, no.

Now, just in case the second option doesn't sound appealing, I will direct you to the rose garden in the park in Eatontown on Rt. 35 S, just south of 537, next to the Mobil station. All of these roses are "no spray" meaning that they get no or very little blackspot and don't lose their leaves if they do get any. There are are a few more newer roses on the market that are also no-spray and do well here. This is your best option if you don't want to use commercial fungicides.

Back to the first option. If you don't have a lot of roses, you can try Bayer Advanced All-In-One. It is a combined fertilizer, systemic fungicide and systemic insecticide. I have had reports that it works well. If the idea of a systemic insecticide is not attractive, then you will have to spray the fungicide. Bonide Infuse (same active ingredient as Banner Maxx, if you read about that one on the Roses Forum) is very effective, needs to be sprayed every two weeks, and last year Brock Farms in Colts Neck had it in stock. this is a "systemic" fungicide, which keeps any blackspot from emerging. I hear that Bayer Advanced Disease Control is also good, I haven't used it. You will also need Mancozeb (or Manzate), which is a "contact" fungicide. This helps suppress any existing blackspot. You can mix the two together and spray them every two weeks.

You have to start spraying soon after pruning, and continue to spray throughout the growing season, through September. Once you see blackspot, it is too late. The key is prevention.

If you are available this coming Saturday, the Jersey Shore Rose Society is holding their monthly meeting at the Womens Club of Little Silver, right across the street from Sickles Market. Beginner's Q&A starts @ 12:30, general meeting @ 1:30. You may sit in on one meeting without being a member.

On the JBs, if you don't want to use a commercial insecticide, then those options you gave are pretty close to it. Some people have tried Milky Spore or BT (sprayed in the lawn to kill the grubs), but for these to really be effective you have to do your lawn and your neighbors too. Oh, and on those traps, if you MUST use them (I won't), then you need to place them as far away from the roses as possible. Merit (imidicloprid) is a very effective insecticide for JBs.

Bottom line is that if you want to stay with natural or organic remedies, then you have to get disease resistant roses. If you just HAVE to HAVE hybrid teas, then you've got to treat with a fungicide. Happy to answer any more questions.


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RE: New to forum. Not new to blackspot.

Lime-sulfur is a more benign fungicide. I read an article on mixing something as benign as baking soda (I think) with Wilt-Pruf - the Wilt-Pruf sealed the leaves against fungal intrusion - you could google.

Heritage, Golden Wings, Konigen von Danemark, Country Living and New Dawn don't get any black spot for me - I don't spray at all.

Japanese beetles - I'm just hoping we haven't such a bad year for them this time around. Praying mantises don't like them by the way. I fed one a mating pair (which went on mating while the mantis groped them) and when it finally took a bite, it spat them out. Birds don't seem to like them either.


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