mukesh_thiru
Newly Registered
Posts: 3
Joined: Tue Jul 06, 2010 2:43 pm
Location: Arizona

Black and Yellow leaves - Please Help

I got a rose plant around a month back and it had been doing very well. It is planted in a 12 inch pot with miraclegro potting mix. I have been watering the plant daily either in the morning or in the evening.
I live in Peoria, Arizona, US. Recently the leaves started turning black, then yellow and started withering. Not sure if it is due to over- watering or salt content or heat. Somebody please advise.

luis_pr
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Posts: 815
Joined: Sun Jul 05, 2009 12:31 pm
Location: Hurst, TX USA Zone 7b/8a

The fungal disease Black Spot will cause leaves to develop black spots and then the affected leaves will turn yellow and fall. Are you familiar with black spot? Could this be the cause? A picture might help tell for sure.

mukesh_thiru
Newly Registered
Posts: 3
Joined: Tue Jul 06, 2010 2:43 pm
Location: Arizona

Made some changes but still some problems

I took all the leaves which has fallen off the plants, bought fertilizer and pesticide. The leaves are drying. I water it once in two days. I don't spray water to the leaves.
As I mentioned I live in Arizona and the temp here is around 110F

See pictures

[url=https://img837.imageshack.us/i/imag0036.jpg/][img]https://img837.imageshack.us/img837/972/imag0036.th.jpg[/img][/url]
[url=https://img833.imageshack.us/i/imag0035.jpg/][img]https://img833.imageshack.us/img833/3826/imag0035.th.jpg[/img][/url]
[url=https://img837.imageshack.us/i/imag0033.jpg/][img]https://img837.imageshack.us/img837/7629/imag0033.th.jpg[/img][/url]
[url=https://img837.imageshack.us/i/imag0032.jpg/][img]https://img837.imageshack.us/img837/6353/imag0032.th.jpg[/img][/url]

The Helpful Gardener
Mod
Posts: 7493
Joined: Tue Feb 10, 2004 2:17 am
Location: Colchester, CT

Luis was correct, you have black spot.

It is a fungal disease. Try copper sulphate as a cure...

HG
Scott Reil

mukesh_thiru
Newly Registered
Posts: 3
Joined: Tue Jul 06, 2010 2:43 pm
Location: Arizona

Neem Oil

Can I use Neem Oil for fungal Disease?
The Helpful Gardener wrote:Luis was correct, you have black spot.

It is a fungal disease. Try copper sulphate as a cure...

HG

cynthia_h
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Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

Neem is recommended for insect control. I'm not familiar with it in treating plant diseases. There are several recommendations on this forum for either a solution of milk, diluted with water, *or* a solution of baking soda, diluted with water, to combat fungal diseases.

Cynthia H.
Sunset Zone 17, USDA Zone 9

The Helpful Gardener
Mod
Posts: 7493
Joined: Tue Feb 10, 2004 2:17 am
Location: Colchester, CT

As it is an oil, it can be a decent anti-fungal, although the "cure" is mechanical (oil smothering the fungus and fruiting bodies) rather than chemical. But when I am on neem patrol for bugs, I often spray the powdery mildew, and it does knock it back pretty well...

But I will use copper sulphate on occasion to really get rid of it, and milk sprays as a preventitive once a week.

HG
Scott Reil

luis_pr
Greener Thumb
Posts: 815
Joined: Sun Jul 05, 2009 12:31 pm
Location: Hurst, TX USA Zone 7b/8a

I could not identify for sure if you were mulching. Mulching the rose might also help you, mukesh_thiru.

One question. What material is the pot made of? Seems metallic looking? If it is, I would not let it get too much direct sunlight as it may dry out the potting soil in contact with the metal quite fast.

professorroush
Full Member
Posts: 14
Joined: Mon Aug 16, 2010 12:12 am

Hate to disagree, but I don't think that's blackspot. Most of that damage, especially on the leaf edges, is caused by too much dryness; or letting the soil get too dry between waterings. I didn't see any leaves with the characteristic black spot lesion (look on the internet for pictures).

The Helpful Gardener
Mod
Posts: 7493
Joined: Tue Feb 10, 2004 2:17 am
Location: Colchester, CT

The Prof has a point; you usually see more yellowing than just browning in the leaf with black spot (although the black lesions are not a necessity despite the name). I made a knee jerk call on that one, and the Prof seems to be a pretty good second opinion...

HG
Scott Reil

professorroush
Full Member
Posts: 14
Joined: Mon Aug 16, 2010 12:12 am

:wink: I'm not a rose expert, but I did stay at a Holiday Inn Express Saturday night.

...And I grow about 150 roses in one of the most hot, humid, inhospitable environments in the US. :)

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