Kitchen Garden Forum

I am growing 5 lots of potato-Rocket, Anya, Charlotte, Sarpo axona and Cara. My problem is with some of the Rocket plants. Those affected have smaller haulms than those not affected and they have now started to wilt. The stems are swollen in places and there are small swellings arising from the stem at ground level -they don't look like potatoes. The plants do not seem to have produced any tubers in the normal manner. I have looked in the soil and cannot see any pests there apart from the odd slug. I live in the Channel Islands and they are grown in well drained soil that was manured in the winter and I also rotate each year.
Anyone know what this is and what I do about it?

Hello Jane

I'm sorry to learn of the problem with your Rocket potatoes and I am not sure what disease or pest has caused it. If the soil the rocket is grown in is good then possible problems could be the potato eelworm or less likely blackleg. There are sites on the internet that would show pictures and examples of potato pest and diseases so hopefully someone more expert could put the appropriate link on.

Other than that you could possibly photograph the affected plants and ask the many growers on Jersey, but DON'T take the affected plants to their farms!

If they are wilted with no tubers I would dig them up and burn them.

Best of luck

Barney

Thanks Barney

I am a member of the RHS so after exhausting the sites on the internet I have sent a sample of soil and the plant to them for help .I have also contacted Thompson &Morgan who I bought the tubers from for help but have not heard anything as yet. I have lifted all affected tubers the others look OK but have not checked for any tubers yet

Jane

It may be completely unrelated to Jane's issue, but out of around 25 Cara plants, I have 3 which are stunted and with withered leaves. These are in amongst healthy looking plants.

I'd be interested in any feedback.

Hi Colin

Will post a note as soon as I get a response fromT&M or RHS

Jane

I have had a reply to the samples I sent the RHS . The culprit is stem canker and black scurf (Rhizoctomia solani). It is spread by infected tubers and encouraged by dry spring weather followed by periods of heavy rainfall which we have had. There is no treatment for the problem and infected plants should be lifted and destroyed. Crop rotation and shallower planting help and early lifting reduces tuber infection- they will not store. The good news is that no more plants are showing sign of the problem and those harvested look OK on the earlies. Fingers crossed