Backyard Aquaponics
A place to discuss aquaponics

Hi all,

I'm looking for advice from the green thumbs out there.

While I was tidying up around the AP system, I notice all my tomato plants had (to different degree's) something wrong with the leaves. The leaves seem to have scattered brown spots on then, that as they get worse end up looking like this:


To my uneducated eye, it looks like something fungal (but being a black thumb, I thought I would get a second opinion ).

Is this a pest or disease of some kind?? And if so, should I be worried / do I need to do something about it / how should I treat it??

Cheers
Sam

Looks like powdery mildew to me.... just pull off effected leaves. If it is spreading you may have to get rid of the plant.

Unless you can actually see the hairy, or puffy lookin fungal spores growing on the leaves... then I would say it's not powdery mildew. It looks like a classic case of Potassium deficiency, or maybe Magnesium, but that is less likely.

Are the older, lower leaves on the plant showing slight yellowing between the veins?

Potassium deficiency is common in AP systems, especially young systems, where people have planted fruiting plants before the nutrient bank has had time to build up, which usually takes 6-12 months to build up sufficiently for successful crops of Tomatoes, Capsicums etc. Even established systems may require the addition of some Potassium when growing heavy feeding and fruiting plants.

You can add Potassium bicarbonate (sold as Eco-Fungicide) to your system, at 1 heaped teaspoon per 1000L, but it will buffer the system pH up slightly, so I would only do this if you pH is in the 6's. If your pH is 7.0 or above I would only use it as a foliar spray

I'd sayTMV... tomato mosiac virus.... cut off all affected foliage... and burn it...

You can remove all leaves below any fruiting truss anyway...

If you handle the plants... wash your hands before handling any others.. especially cuccumbers, melons etc... as you can spread the virus... the mosaic viruses are essentially similar across species...

http://aggie-horticulture.tamu.edu/vege ... er/leaves/

Spotted wilt or altarnaria canker by the looks

Pull off all effected leaves and spray with eco rose might help

Rupe may well be on the money (http://apps.rhs.org.uk/advicesearch/pro ... px?pid=250)... but don't tell him!

I have seen potassium deficiency in tomatoes end up in similar looking damage to the plant, but usually the older lower leaves on the plants will develop distinct yellow patches between the veins well before the necrotic patches develop, hence why I asked: "Are the older, lower leaves on the plant showing slight yellowing between the veins?"

Cheers.

I have that all the time. I just pull off the affected leaves.

Early blight which shows as leaf yellowing from the bottom up is pretty common and yes pulling off effected leaves and binning them should keep it manageable till the weather warms enough to stop it. If you do get this be sure at the end of the season to remove all traces of tomato plants/leaves etc. Also don't let any leaves touch the soil, and prune leaves off to increase ventilation.

Actually if it's PM just spray the plant with milk. (This was proven not a home remedy )

So I got stuck into the AP on Sunday and did a couple of things.
Firstly I strung the tomato's up some more to get them off the gravel and spread out a bit.
Secondly I tried to cut out as much of the infected leaves as I could, and in the process thinned out the plants to let more air flow through.
Finally, I sprayed all the AP plants with a mixture of Eco-Rose, Dipel (I've been finding a few crawlies), and seasol (cause it never hurts).

So I'll see how things go after this treatment, plus with some warmer weather coming. Hopefully I won't have to pull the plants out.

You can NOT use the majority of commercial fungicides in AP, and should avoid oil and detergents as they can effect the fishes respiratory system.

i was going to post up pictures of my tomatoes but then realised there is absolutely no point as my leaves are identical. The same disease or whatever it is has spread to my watermelon but is not affecting any other plants.

today i pruned the crap out of my tomatoes. the bottom 1m or so now has no leaves at all, just fruit. i removed every single leaf with even a spot on it. i also sprayed the crap out of every plant and even the gravel with eco-fungicide. we'll see how we go. if i lose my tomatoes, along with the fact that my strawberries are not producing at all I'll be very annoyed.

so far the only decent harvest I've had has been lettuce and i don't really like lettuce that much.

I find the older leaves on established tomato plants often go like the picture and had it on my watermelon this year. Taking them of usually does the trick. As the season progresses I generally strip off the lower leaves anyway to let sun on the tomatoes (in the UK, we are somewhat lacking in that round yellow thing) and air circulate.