Plant (Zinnia) spot Quandry

6 years ago

I have to Zinnia containers that started out beautifully, purchased in bloom from a garden center. About two weeks ago, I started seeing spots on the leaves. Now, as the pics show, some of the flowers look diseased/unhealthy and more of the leaves are turning up with these patches of spots. Anyone have a clue?? I have been using a spray for aphids and other bugs that eat leaves since I saw the first spots, but I guess it's not working. How can I save them? They are my favs.

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Comments (7)

ken_adrian Adrian MI cold Z5
6 years ago
what are you spraying with,. and why are you repeatedly spraying it ???

did you actually ever seen any bugs to spray???

i see no damage in the second pic.. so i dont think you need to keep spraying ...

btw.. never spray a plant in full sun ... it can damage leaves ...

ken
whathousework3
Original Author
6 years ago
Thanks for the response. The healthy looking pic is the before. the other 2 show the issues. I have been, once weekly, spraying with BioAdvance Rose and Flower insect Killer.
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whathousework3
Original Author
6 years ago
Also Ken, I have not seen bugs when I turn the leaves over, but something has to be causing this. So I thought maybe white flies ?????
ken_adrian Adrian MI cold Z5
6 years ago
NEVER spray anything.. unless you find a culprit to kill .. speculation is not good enough ... and then.. dont spray again .. unless they return after the first kill ...

ken
gardengal48 (PNW Z8/9)
6 years ago
It is NOT an insect problem! The flower in the first photo is just past its prime....it can be removed or deadheaded. And check out bacterial leaf spot on zinnias. Very common with hot, humid weather and overhead watering. That will require treatment with a fungicide, not an insecticide.

And water the soil only, not the leaves.
whathousework3
Original Author
6 years ago
thank you for the counsel. any fungicide recommendation? I'll work to save them.
zen_man
6 years ago
last modified: 6 years ago
Hello whathousework,

Gardengal is correct, what your zinnias have is not an insect problem. She mentioned Bacterial Leaf Spot, and if that is correct, nothing that you can spray will get rid of the bacteria. Yellow halos around the dark spots is a symptom of bacterial infection, and that would indicate incurable Bacterial Leaf Spot.

However, sometimes Alternaria Leaf Spot will have a little yellow border and there is a possibility that your problem could be Alternaria Leaf Spot, which is a fungal disease that can be controlled with good fungicide sprays. The BioAdvanced brand that you mentioned is a good one, and they make a BioAdvanced Disease Control for Roses, Flowers & Shrubs that could be effective against Alternaria Leaf Spot of zinnias. It is systemic, which means it is absorbed into the plant and becomes a part of it, so that new growth is protected. Not forever, but for more than a week. Non-systemic sprays can get washed off the next day, or possibly even the same day you spray them.

ZM (not associated with any product or vendor mentioned or linked)