Gardening Questions: Black Spot

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dipsydoodle Newcastle upon Tyne (United Kingdom) October 2, 2008 6:31 AM	I am sure I posted this yesterday but I can't seem to find it, maybe I pressed a wrong button, so apologies if it is in twice. We have a pear tree in the garden which has caught black spot, can anyone recommend any good treatments before it transfers to the other trees/plants near it? Many Thanks
ecrane3 Dublin, CA (Zone 9a) October 2, 2008 9:27 AM	Only certain plants are susceptible to black spot, so it won't spread through everything in your garden. If you've got other pears or things like apples and roses they can get it too, but if it's other sorts of plants and trees then you'll probably be OK. The good news is it's unsightly but not fatal. Here's a link that talks about treatment [HYPERLINK@www.ipm.ucdavis.edu] This year when the leaves fall it's really important to pick all them up off the ground and dispose of them, otherwise the fungal spores are left there and the tree's more likely to get it again next year. I'll be honest though when you have plants that are susceptible to this, they'll often tend to get it just about every year no matter what. You can try some preventative spraying in the spring before any symptoms show up, that can often be more effective than trying to treat it after the spots are already there.
dipsydoodle Newcastle upon Tyne (United Kingdom) October 3, 2008 5:40 AM	Thanks. We also have an apple tree but I've not noticed it on there yet. One of our minature roses has gotten it, but I know roses are susceptible. Also my poor spider plant managed to catch it :-(. I did buy some black spot stuff from the garden centre yesterday to use :-). Thanks
flowerfantasy Washington, IN (Zone 6a) November 6, 2008 1:19 AM	I have a couple cases of black spot too and I was told to mix 1 part bleach and 4 parts water and spay the leaves on both sides and should take care of it but you do want to get rid of any leaves that have it already. Supposedly epson salts works as well at the same mixture.
dipsydoodle Newcastle upon Tyne (United Kingdom) November 6, 2008 8:02 AM	Thats a good idea the bleach and water although it would stink! We have gotte rid of all the leaves, Now all the trees have no leaves anyway so its ok/ We'll give them another spray when the leaves start to grow again in the spring.
dp72 Woodway, TX (Zone 8a) November 6, 2008 10:11 AM	Daconil or Funginex are proven treatment agents for black spot. There is a lot of anecdotal advice out there for kitchen remedies, but none of them have been subjected to double-blind scientific studies.
ecrane3 Dublin, CA (Zone 9a) November 6, 2008 10:57 AM	1 part bleach to 4 parts water also sounds a bit on the strong side for what I'd want to spray on a plant--if you use bleach that's too concentrated it can hurt your plants. Personally I'd probably go for a fungicide that's designed for use on plants.
flowerfantasy Washington, IN (Zone 6a) November 6, 2008 7:29 PM	Well if you mix the 1 part to 4 parts in a gallon jug what do you have? this was gave to me from professional gardening center and also was found on a web site as a formula for this problem so if your afraid to use it don't.
dp72 Woodway, TX (Zone 8a) November 6, 2008 7:44 PM	I give up. If I mix 1 part to 4 parts what do I have? There is sound advice available at some "professional garden centers" and occasionally on the Internet. Unfortunately, people who depend on websites for information on health are much more likely to find quackery than scientifically proven advice. I'm afraid that is often true for advice on growing plants, too. Anybody can put anything on a website. Just because they may fervently believe what they advise doesn't make the advice efficacious. People tend to uncritically repeat things they have heard. The placebo effect is an important factor also. If I were to put fairy dust on the leaves of a plant infected with black spot, and then the weather got warmer and the rains stopped and the humidity dropped very low and the sun shone brightly for several weeks, the black spot might improve or go away. I might credit that to the fairy dust when actually it was the change in the weather to conditions that don't favor black spot.
dipsydoodle Newcastle upon Tyne (United Kingdom) November 7, 2008 7:33 AM	We have a funcicide thing from the garden centre :-). I wouldn't trust bleach on my trees (edible), although if it works it a great idea.
JuneyBug South Central Ozarks, MO (Zone 5b) November 7, 2008 9:47 AM	That is the mixture that I use to kill the moss and mildew on my walkway and deck. If it's strong enough to do that, the the gardener probably mis-spoke and meant 8 - 1 or something like that.
dp72 Woodway, TX (Zone 8a) November 7, 2008 10:22 AM	Any mixture of bleach and water strong enough to "kill" black spot would do cellular damage to the plant tissue to which it was applied.
JuneyBug South Central Ozarks, MO (Zone 5b) November 7, 2008 1:52 PM	Is there any way to keep black spot from happening to my peonys? A local master gardener has said no. 'scuse me for not beleiving, but there has got to be some way. I am in the humid area of the country. By this time of year, my plants are covered. What works?
ecrane3 Dublin, CA (Zone 9a) November 7, 2008 2:02 PM	Unfortunately I think your master gardener is right--black spot is one of those things that if you have plants that are susceptible to it, it is difficult to 100% prevent it. Picking up any fallen leaves, making sure to have good air circulation around the plants, and doing some preventative treatment with a fungicide early in the year before symptoms show up can help, but you may end up with black spot anyway.
JuneyBug South Central Ozarks, MO (Zone 5b) November 7, 2008 2:08 PM	Ahhh, That's why she said it was hopeless to think it could be gotten rid of. These peonys had been hers 15 years ago. She Knew! This past year was bad. I kept them fertilized and well watered, there just isn't much I can do about the air circulation here on the wrong side of the hills. Thanks for the help, Nan

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