Zinnias - is this Aster Yellows? How can I prevent it?

Amanda G.
4 months ago

Site lost my other post (with details) while I was writing. By this point I ought'a know better than to not Ctrl+A/Ctrl+C as I go. -_- No way can I get it all back from memory.

Long story short, I've grown Zinnias in the window of our loft (urban, full southern exposure, they love it) for a few years now, and after the first couple years, I've gotten more and more sick/deformed plants. This year, only six seedlings survived to planting size and two have bloomed the first time; the pink started developing speckles after two days. A couple other plants also have the same curling/deformed leaves I've noticed before. A friend of mine (about to walk with her masters in some plant-specific biology study, can't recall which) said it looks like Aster Yellows.

I destroyed all my seeds after that year's batch ended in disaster - we're talking over two quarts of carefully harvested seeds, all hand-pollinated and some cross-pollinated and kept separate in hopes of a hybrid. That was close to three years worth of hard work and patience, so let me tell you, that HURT...but I've seen what whatever-this-is does to infected plants and plants sharing the containers. This year I started with seeds freshly bought from the store to rule out infected seed from my stash. As usual, I scoured the planter (and the basin beneath) with bleach cleaner and sterilized the soil a gallon at a time in the microwave, and have kept a close eye on the plants as they grew.

The first bloom to show spotting - two days before, this was a normal, if unevenly colored, pink flower. Usually it takes several flowers to hit this level of speckling.

Closeup of the speckling.

The leaves of the neighboring plant. Heavily curled and deformed...

...and the top was a warped beyond recognition. I cut it off and will be pulling the plant once I'm not coughing up a lung. Considering at least half of the plants are showing the same leaf deformities already, I worry I'll lose most, if not all of them before summer's done. (For the record, these may only bloom through summer outside, but I've kept them going until late November before. Southern exposure, high ceilings, double-pane windows, padded windowsill, and LOTS of PAMPERING!)

Photos from previous instances:

Grown from complimentary seed from the College of the Ozarks nurseries.

Grown from the same seeds. This shows the bizarre delayed doubling I've noticed from some of their seeds. By the time the first ring of petals starts fading, a secondary ring starts sprouting from the center. I've seen these go through up to two extra layers of petals if not deadheaded. Not all end up looking sick so it may just be a genetic abnormality. This one was DEFINITELY sick. Same one later on:

Most of the diseased flower photos appear to have vanished into my hard drive, including the saucer-sized pink one that looked like a pizza with a slice ripped out. O_o THAT ONE was BIZARRE.

Is this, 100% certain, Aster Yellows? If I got it from fresh seed this time, that suggests just destroying the old and starting with new isn't foolproof. Is there any way I can recognize signs earlier on so the plants don't get big enough to spread the infection? Honestly, is there ANYTHING I can do to prevent this from happening again? I love having zinnias in our window and have gotten some gorgeous plants out of it, but this is killing my ability to appreciate them. If I'm going to have to babysit every zinnia I sprout like a prized orchid and STILL have to dig half of them up over disease, I'd rather find something else to grow. Cautiously experimenting with a planter of petunias.

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