Taser
Newly Registered
Posts: 2
Joined: Sun Sep 12, 2021 11:45 pm

What is this disease??? Turning yellow

Hello, Thank you very much for accepting me for this forum. I am from Sri Lanka and new to growing roses. About two weeks back I planted about 20 plants and now in some plants, adult leaves are turning yellow. :? :? :cry: :cry:
photo_2021-09-13_09-16-11.jpg
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Whitish residue on the leaves is Macoceb fungicide

Please help me to identify this condition. Thanks

imafan26
Mod
Posts: 13962
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

I might be aphids. I could not zoom more but I thought I saw some bumps that looked like aphids. Put out ant bait. Move the plant at least 18 inches from the wall. It will provide better air circulation. Fungicide is good. Roses with shiny leaves do better in hot humid environments. Since there are only a few yelllow leaves. Pick them off;
bag, seal and trash. Don't drop them on the ground. Check under the leaves regularly for pests. I regularly blast the undersides of leaves with water early in the morning. It is the only time to do this because the leaves need time to dry off. You want to avoid leaves staying wet all day or overnight. You can use an insecticidal soap under the leaves on soft bodied pests. Oil sprays can only be used if the temperature is less than 85 degrees and only in the coolest part of the day.

Taser
Newly Registered
Posts: 2
Joined: Sun Sep 12, 2021 11:45 pm

imafan26 wrote:
Mon Sep 13, 2021 1:54 am
I might be aphids. I could not zoom more but I thought I saw some bumps that looked like aphids. Put out ant bait. Move the plant at least 18 inches from the wall. It will provide better air circulation. Fungicide is good. Roses with shiny leaves do better in hot humid environments. Since there are only a few yelllow leaves. Pick them off;
bag, seal and trash. Don't drop them on the ground. Check under the leaves regularly for pests. I regularly blast the undersides of leaves with water early in the morning. It is the only time to do this because the leaves need time to dry off. You want to avoid leaves staying wet all day or overnight. You can use an insecticidal soap under the leaves on soft bodied pests. Oil sprays can only be used if the temperature is less than 85 degrees and only in the coolest part of the day.
Thank you very much for the reply. But this is not due to insects. I also checked that.

pepperhead212
Super Green Thumb
Posts: 2852
Joined: Wed Oct 15, 2014 1:52 pm
Location: Woodbury NJ Zone 7a/7b

Welcome to the forum!

I'm not a rose expert, but I have seen that many types of black spot and other fungal diseases infect them, so the fungicide is probably on the right track.

I see it is in a pot, but I don't see any perlite or other drainage in the soil - it looks just like some garden soil put in the pot, which could have a drainage problem, especially if you are having a lot of rain.



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