Newly Registered
Posts: 1
Joined: Tue May 31, 2016 10:24 am
Location: Ferndale, WA

Black spots on sunflowers, neem oil NOT helping.

Anybody have any ideas or experience this before? I believe this is a velvet queen sunflower (if it's not, it's an appolos ring, or talk border mix of some type),these are all I started.

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Super Green Thumb
Posts: 2115
Joined: Wed May 21, 2014 9:26 pm
Location: Upstate, SC

Sounds fungal. I can't really see much from your photos, but they are generally prone to fungal infections. Baking soda and milk, neem oil, peroxide, copper fungicides. Any of those will help with prevention, but once the damage is done, the plant won't heal. The spots will persist. I'd remove what you can of the worst of the spotted leaves, and then do regular (you have to be consistent) treatments weekly to prevent.

I am getting good results with 1/4 cup neem oil extract and 1 heaping tablespoon of baking soda in 2 gallons of water weekly.

Posts: 13904
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

Most fungicdes work better is you start them before the problem shows up. Fungicides should be preventively used whenever wet humid weather prevails.
Make sure the plants are not planted too close together and they get plenty of air circulation in full sun.

Taking off the leaves are a good idea as it will also open up the plant more.

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