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Bigsmoke
03-29-2004, 07:00 PM
Anyone here good with diagnosing diseases in ornamentals? I have some pics of English Ivy and Azaleas. Both problems have me kind of confused. Anybody willing to take a look would be appreciated.:D

Ric
03-29-2004, 07:23 PM
BigSmoke

Can you post a picture??? A couple of good pictures would go a long way toward getting you help.

Bigsmoke
03-30-2004, 08:35 AM
English Ivy on shady side of house. Initial diagnosed as spider mites.

Bigsmoke
03-30-2004, 08:37 AM
Azalea with yellow and dying leaves. Branches still green.

Ric
03-30-2004, 05:02 PM
BigSmoke

The English Ivy looks like one of the Cercospora Leaf spot fungi. This is common in areas that stay wet or have lack of Air movement. However it can infect Full sun dry plants also. A good systemic Fungicide will slow it down. You should do preventive treatment on these plants if you don't want another out break. However if you look around, you will find a lot of shrubs that have this blight.

The Azaleas, I can not tell a thing from the picture. However they have a consistent weakness all over. Now Root fungus and herbicide damage ( Chemical burn of any kind ) will show similar Signs. Can we rule out chemical burn??

You might want to post some more picture of closeups in order for someone to help you.

philk17088
03-30-2004, 06:51 PM
Get the Johnson and Lyons "Diseases of trees and shrubs" Excellent reference book with good color photos of plant problems. It's put out by Cornell University Press. They also have one on Insects that feed on trees and shrubs.

The azaleas may have phythoptera disease, it is soil borne and infects roots stems. No treatment for it. Also it persists in the soil so if you replace don't use another azalea or rhodo.

Grassmechanic
03-30-2004, 09:14 PM
Seen azaleas look like that when the ph is too high.

Kevin M.
03-30-2004, 09:35 PM
Phythoptera is certainly treatable PhilK. I just treated for this today at a clients property on some azaleas that I took a root sample and it confirmed the disease which is very treatable with Subdue soil drench. Then after the treatment has been applied you will have to apply it again to suppress the disease next year as well. Also keep the shrub fertilized with some 14-14-14 to keep the disease from taking over again.

heritage
03-30-2004, 09:49 PM
Phytophthora Root Rot can be treated on azaleas but BEWARE when using Subdue as a soil drench as azaleas are sensative to this product (read label). I have found Aliette works better and is MUCH safer on azaleas. I prefer the 5 lb per 100 gallon FOLIAR APPLIED rate at the proper time of course....and a follow up spray 6 weeks later if it's a wet season and pressure is still high for this disease. How about some mulch around those azaleas as that will help to supress Phytophthora root rot..........

Pete D.

philk17088
04-05-2004, 09:34 AM
Originally posted by Kevin M.
Phythoptera is certainly treatable PhilK. I just treated for this today at a clients property on some azaleas that I took a root sample and it confirmed the disease which is very treatable with Subdue soil drench. Then after the treatment has been applied you will have to apply it again to suppress the disease next year as well. Also keep the shrub fertilized with some 14-14-14 to keep the disease from taking over again.




Suppression seems to be the goal with the treatments listed. I had a Penn State hort extension agent look at a garden with only azaleas and rhodos in it and he said that the only plan was to keep up with sanitation and told me to avoid fertilizing at all. Now I'm wondering about his knowledge.