Swiss chard rotting/diseased?

 I'd appreciate your help.  I've planted squares of Swiss chard in different places of several boxes, yet this rotting and drying up of the edges of the leaves is happening throughout my different plants.  There are no bite marks, and there aren't any egg masses.  No frass.  

The back of the leaf in the foreground has what looks like black mildew/mold on the back of the tip that's showing, and the "windowing" on the small leaf in the background apparently results in holes.  The small leaf's tip has wilted altogether and is folded over on itself.  No eggs in the fold, no aphids.

I thought they were slime trails, but the slugs don't like the eggshells I sprinkled around the bases of the plants.

It's been hot and muggy, but it's supposed to be.  I've trimmed away cucumber and tomato leaves that might stifle the air around the fruit, and the chard itself isn't crowded.

In case it matters, elsewhere I've been cutting away tomato leaves with what looks like early blight (little yellow/black spots in the middle of the leaves, right?), and zucchini leaves that have turned yellow.

Another leaf:

You're being visited by leaf miners that prefer beets, chard, and spinach.  Their 'tracks' aren't as distinct as the tracks left in other plants by other types of miners.

The adult looks like a very small house fly. They lay eggs on the bottom of leaves like this:

Each white egg is less than 1/8 inch long.  The larvae get in between the layers of the leaf to feed.

In your pics, you're seeing the results after the leaf miner is long gone.  Fresher damage looks similar to this:


The first two years I had them, I was able to manage the damage by searching and destroying the eggs.  It works for the miners on my chard and spinach, but they much prefer my beets so  I've had to resort to growing all my beets in boxes covered in tulle.  

I haven't tried pesticides, so I can't offer suggestions for them.

OK, I get covering certain plants with tulle, can we newbs get a link to what Ned's pollination and what can be grown under tulle?

I also experienced that kind of damage on my beets and to a much lesser extent on my swiss chard.

Scorpio Rising wrote:OK, I get covering certain plants with tulle, can we newbs get a link to what Ned's pollination and what can be grown under tulle?

Who's Ned?  

I don't recall seeing a list, but if you start a new thread on that topic so we don't derail this one, I bet we can come up with one.

Thank you, Boffer.

I just went out there and yes, there are eggs, but they're about 1/2 millimeter long!  And I had been wondering why there were so many little flies.  OK! 

It may be too late for tulle, because I would just trap newborns in with their favorite food. I am preparing a night raid with organic pesticide, which I know is just as poisonous as any other. 

I'd best start reading up on IPM, since the praying mantises don't seem to have hatched and survived.



Scorpio Rising:  I guess you can probably grow anything under tulle, but that means that you'd have to get out there under the tulle to pollinate by hand in the wee hours pretty much every day. 

The tulle will keep pollinators out as well as pests.  

Right now I have the lone strawberry that the chipmunks left me under a chicken wire cage covered with tulle, because they get right through the chicken wire and they get confused by the tulle.

Sorry, I don't know what Ned's pollination is.

boffer wrote:Who's Ned?  

Darn that auto-correct! Needs!

sanderson wrote:

boffer wrote:Who's Ned?    

Darn that auto-correct!     Needs!

I know.....Ned....such a great guy with the pollinators.....lol

point, I met up with the leaf miner for the first time ever this year, too...in my chard. Then there seemed to be a couple in my collards. I pulled off the leaves and threw them in to the garbage, tied it up and tossed it in the dumpster at work. Those little flies went right thru the 1/4" netting I'm using. Can't believe I have to start using tulle again. Chard was always so reliably pest free for me.

In the New Victory Garden book, he says that the miners stop at some point. I think it's July or Aug. I'll find out tonite and let you know tomorrow. Another option to tulle would be to wait & plant those crops after the miners egg laying cycle.
CC

CC, Thanks for checking.

Just as you think you have a handle on how something grows, something changes. And you're reminded how little you know. 

This chard is spindly, while last year it was full, and I couldn't give it away fast enough.

Well, I bought enough tulle to cover a couple of boxes, and I have an empty box from the garlic I just harvested, so I'll just sow some again.  I can always pop a cold frame on the box if the yield's better.

Well, the New Victory Garden says July is the end, but the old Victory Garden says they re-appear mid Aug.  Beats me.


For all you great thinking minds, a question I'm pondering lately:
Which would be the best chard seeds to save - the plant that didn't get the miners so didn't have to defend itself, or the plant that had them (only on 2 leaves) and may have built in defense now?
What say you?

CC

Here's a good description of a leaf miner's life cycle.

The first time I tried tulle to control leaf miners, it didn't work.  Either the pupae over-wintered in the MM, or I didn't secure the tulle tightly enough.  The box was made of 2x's so I layed the tulle across the top edge of the box, and then layed a 1x2 on top of the tulle to keep it in contact with the box.  I put a yellow sticky card in with the beets, and I'm amazed how many bugs got in despite the tulle.  Although there was quite a bit of damage to the beet leaves, I was still able harvest some beets.

The next time I tried it, when I planted the seeds, I sprinkled DE lightly on top of the MM, and on the top edge of the box.  Then I screwed down the 1x2s to make sure there wasn't space for bugs to squirm through.  That's given me the best looking crop of beets that I've had in several years.  There's still a few misc. bugs stuck on the yellow sticky card, but they haven't caused any damage.

As to your question, beats me.  But if you removed the damaged leaves after finding the damage, would the plant have had a chance to do whatever it does to protect itself?

Boffer, what kind of head space was there between the tulle and the MM?   I'm thinking that it would be a pain to unscrew the slats whenever you need to get in there, so how long did you keep the tulle on?

I was thinking of putting the tulle over hoops so there'd be plenty of growing room. 
 
Thanks for the idea of the DE put on at the beginning of the process.

And CC, now I know there's no safe time to start again if I want a fall crop.  Thank you.

I'm keeping the tulle on from seeding to harvest.

This box is roughly 2x5, and only has beets in it. The frame is 20 inches tall.




Most of the watering I do with a wand, spraying right through the tulle.  I open the long side maybe every 10 days to thin and weed.