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suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 7:42 am
by demi
Iv got 2 sweet potatoe tubers that were rooted in water and i was taking cuttings from to plant outside over the summer.
I then stuck the 2 tubers into a big tub in late august and iv now brought it inside to continue growing over winter and hopfully get some potatoes out of it.

Some of the leaves are turning yellow and iv been nipping them off. I just googled yellow leaves on sweet potatoes and it says they are prone to 2 types of fungus, Vermicillium and Fusarium. Iv also just noticed on the stems of some of the leaves there is this opaque white stuff, like little balls, its not eggs. Not all the yellow leaves have this and some of the healthy green leaves have it too. I'v manually cut off all affected areas that i can see. Im not positive that the white stuff and the yellow leaves are connected, can't find pictures on google to confirm. And i don't think its powdery mildue because its like little opaqu balls, not powder and its dotted up the stems. Iv looked at pictures of the mildue and im sure its not the same thing.

Any one got any ideas?

Also what can i treat it with organically? Its in the livingroom so i don't want to spray it with harsh chemicals. Whould soapy water work?

Here's the link from what came up when i googled it: http://www.ehow.com/way_6175204_problem ... -vine.html

Its either a fungus or a deficiancy, or maybe both. Can i add the ash from the fire into the pot to feed the soil? We don't have money to buy fertalisers or fungaside.

Re: suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 10:13 am
by GeorgeSalt
Can you get a photo (or four)? showing the yellow leaf, showing the opaque balls, showing the plant as a whole, showing where the plant is situated.

Yellow leaves could be a mineral deficiency, but it could also be over-watering (which would encourage funghi and moulds) or lack of light (which would weaken the plant and could encourage pathogens). It's difficult to know which pathogen may be involved, and whether it's the primary problem or a secondary problem on top of something more fundemental.

Re: suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 11:34 am
by demi
I would of taken photo's if i could but my camera isn't working! :(

Maybe overwatering could be the problem although i don't water it often but the huge tub its has never gotten dry. It is in the warm livingroom on south facing window. It got eaten by somthing when it was outside, possibly snails and the leaves have lots of holes, mostly circular. The yellow on the leaves is spread out, not really mottled more an even tone getting yellower or greener on the healthy bits. Some of the yellow leaves are getting darkish brown patches on them, but those leaves are eaten and i thought it might just be them drying up because they're damaged, lots of the patches are around the edge of the holes like they are drying up. The white opaque wee balls are mostly all on the stem of the leaves and nearly none on the actual leafs. They are quite close together on the badly affected bits then im finding more spread out on other parts of the plants. They look almost like little jelly balls but are dry and slightly hard to touch, I can pick some off and they are slightly gritty.

Re: suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 11:51 am
by GeorgeSalt
Could it be scale insects? There's a lot of variety in their appearance. If it is a dab of methylated spirit applied with a paintbrush may help - or just pick them all off. Or is it just balls of hardened sap leaking from the plant?

It does sound like multiple problems, picking them apart is going to be nigh on impossible until you can borrow a camera for a few photos.

Re: suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 1:07 pm
by demi
Pretty sure its not scale insects, or any other bug. The sap sounds lik a possibility. Why would sap leak out of the uninjured stems?

EDIT: I'm not getting anything on google for leaking sap.

Re: suspected fungus on sweet potatoes

Posted: Fri Nov 09, 2012 7:29 pm
by The Riff-Raff Element
demi wrote:Why would sap leak out of the uninjured stems?
No idea. Sorry.

Without seeing piccies I'm going to revert to the default which is magnesium deficiency causing the yellowing. The solution to this is a dose of Epsom salts - hydrated magnesium sulphate (just show MgSO4.7H2O to a pharmacist). The brown patches are - I'd guess - some kind of mildew, so Bordeaux mixture might slow this down.

Re: suspected fungus on sweet potatoes

Posted: Thu Jan 10, 2013 10:25 am
by demi
I found my camera and the USB cable so i'v got pictures now.
I cut off all the bits with the wee opaque balls/droplets or whatever they were and they've not come back. But the leaves are still turning yellow and wilting, see picture. My husband thinks thats just what they do, or maybe they don't have enough light. But i'm sure when we had them in the summer they were not doing this and they were really healthy. Iv got more tubers sprouting in glass gars of water and they are also doing it. The picture is of cuttings taken from the original tubers which are planted in a big pot on the living room window. All of them are doing it, the new tubers in water, the old tubers planted in the pot and the cuttings. I hope they are not diseased. Also iv got lemon grass and tomatoes on the same window sill and they are also doing it, some of the leaves are dying. I started with 7 or 8 cherry tomatoes cuttings and im down to the last one now, the others all lost their leaves and died. They might just be struggling from lack of light but i hope they are not all infected with the same thing.