Backyard Aquaponics
A place to discuss aquaponics

Over the past few weeks, my cucumber plants have taken a turn for the worse.

The system is 2-3 years old, stocked with Silver Perch. I salted the tank at around Christmas to 3ppm as a precaution, as I lost 3 fish to something (possibly fin rot or the heat wave we had in Perth). I also added some chelated iron, hoping to give the plants a boost.

The levels this morning were 7.8/0/0/20. Nitrates used to be around 80 before the fish died.

The rest of the bed is pretty healthy, particularly after the chelated iron hit.

Viagra jokes aside, does anyone know what's wrong with my cucumber??

Looks like powdery mildew to me.

It has been so humid here in perth, mine are copping it too.

Grab a glass of milk and click on the link below:

http://www.backyardaquaponics.com/forum/viewtopic.php?t=12059

I was under the impression cucumbers were sensitive to salt.

mine went the same way too. Didn't have any salt in the system, so could well have been high humidity and PM. I sprayed my pumpkins with ecofungicide this morning as all the lower leaves had died off and the stems had a greyish coating. Upper leaves are fine, though if they start dying I'll rip the plants out.

I read a reference saying there would be a 10% drop in yield of cucs at a 1.5ppt concentration of salt, so 3 ppt may be lowering their resistance.

This may also be useful.

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex4246

thats a good link - 1 mho = 1 siemens, and

1dS/m = 1000 EC (uS/cm) = 640mg/kg (ppm) = .640 PPT

the units they are quoting of mmho I'm guessing are milli mhos per cm (though not sure on that) so

4mmhos --> 4 x .64 = 2.6PPT?

hopefully someone from a hydro background can confirm. If so 3PPT may well start affecting the cucs

Mine look the same with no salt as well

does not seem like salt is the issue then... have you been spraying with eco rose? Mine were pretty much cactus after I came back from a 1 week trip away over Christmas.

I planted them and let them do their thing.
I got a few cucumbers off it, then got a similar result

The new leaf there looks fairly healthy...

Could it be a sap sucking bug? Whitefly or something like that?

Thanks guys, I've added a few close ups.

rsevs: I used to get whitefly in plague proportions when I had brocolli, but haven't seen them around at all.

mattyoga: I haven't hit it with any eco rose or anything yet. I'll try some milk spray, but I suspect it might be too late. The leaves pretty much crumble like crepe paper.

Hello Fuzzy,
Mine have all done the same thing in the last 2 weeks.
I have had more cucs than my whole family can eat and now I think they are past it.
I did cut off all the affected leaves when I first saw them but then all the new leaves turned as well.
Eco fungiside is good as long as we are both not to late.

Yep I've had similar results the last couple of years both in the AP and in the dirt

Same with me...must just be the heat wave. The ones in ap got killed by my 6ppt salt (sick fish) and the ones in dirt went all yellow and crumbly. Now that the temps have come down to bearable, my dirt ones are picking up again and growing fruit.